Coil/ignitor wiring for Microtech conversion

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archangel62
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Coil/ignitor wiring for Microtech conversion

Post by archangel62 » Tue May 06, 2014 11:59 am

Howdy lads. It's been too long between drinks. My Piazza's Microtech conversion is coming along real well, but the last few wires to sort out are the ignition module/coil wires. I've got a pretty good understanding of how the Microtech works, but I'm still hazy on the Piazza's ignition module wires.

My goals:
1. To keep the tachometer functional.
2. To modify as little of the Piazza loom and engine bay as possible, preferably in a reversible fashion.
3. If possible, to keep the Piazza's original knock protection. I'm not sure if this cuts spark by grounding the coil, or what...

The Microtech is an MT8 V2, which I'm told is identical for wiring purposes to an LT8. It's fuel and ignition, and the CAS input is sourced from the two reluctor wires on the Piazza dizzy. Therefore, these two wires will no longer be going to the ignition module. The spark output of the Microtech is a single wire intended to operate via an ignition module (which I have, along with a matching coil), and can also be used for a tachometer signal. It's basically a low-current version of the coil -ve wire, I believe.

Now, the Piazza. Mine's a 4ZC1-T Australian-delivered turbo. The ignition module is a Denso (Nippondenso) unit with part numbers 8944309331 and 101311-5050 12V. It has 6 wires on it I believe:
Red - usually goes to distributor reluctors - left unplugged as these go to the Microtech instead.
Yellow - as above
Brown - tee'd, this goes to coil +ve and also becomes Black/Yellow into the car's wiring loom, this is ignition +12V from the ign barrel
Green - Unconfirmed, shares a plug with Blue then changes colour
Blue - Unconfirmed, shares a plug with Green then changes colour
Black - tee'd, this to coil -ve and also to the tachometer (becomes Black/Red). This is the igniter's high current switching output for the coil. I believe it also piggybacks to Green with Red rings on the loom, which may supply coil -ve signal to ECGI and TCS (unconfirmed)

Questions:
Does anyone know which wire is the tachometer, and which (if any) is the knock protection, and how it works?

Also, what's a decent source of "Ignition +12V" around there? I'm guessing the wire on the positive side of the coil. I just need it to tell the ECU when to switch on.

Lastly, can the Piazza module take an input from the simple open/closed circuit signal that the Microtech would send? I'm guessing not; I'm guessing it's designed to convert the Reluctor wave signal into a spark.

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Last edited by archangel62 on Fri May 09, 2014 1:11 pm, edited 2 times in total.
Indigo - '76 TX Gemini sedan, G180W+T project,
Abigail - '81 TE sedan, white, G180W ITB project,
New Hotness - TG Gemini drift car, orange, 4ZE1+T
Tardis - 1986 Piazza 4ZC1-T, black, forged, 136rwkw @13psi
Coupe - TX coupe grip car, "do it later", G180W+twin carbs
Trevor aka Jimmy's Gem - Grandpa-spec TD
BA Falcon - Tow car

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Post by IZU069 » Thu May 08, 2014 2:32 am

Alas it's been too long, but as I recall the tacho wire is Black-Red else Green. (Black-Yellow is IGN +12V.)

Though you could use the Piazza ignitor as a digital ignitor (by series connecting a cap), IMO you'd be better off with a more modern unit - ie with current limiting (like the RB Gemini ignitor but flat mounting).


Wires at the Knock Control Unit are White & Red to the ignitor.
Ideally the uTech would have its own knock circuitry but otherwise I suspect the KCU could be used. The KCU should receive the raw reluctor sensor output and supply the delayed signal (if knocking) back to the ignitor. I don't know if it's an override (add delay) system or if the ignition timing always goes through the KCU, though I suspect the former. FYI - knock systems delay the spark; they do not ground the coil (though they keep it grounded longer).


Take power from the OEM "ignition" relay. I don't recall if it's the grey or brown type (LOL!), but the Piazza loom or fusebox has the relay's coil series diode to ensure the EMS is not powered if the battery is reverse connected.
The relay is DPST type - 2 separate NO contacts; one is used for the ECU, the other for the injectors.
Or you could add your own. (But don't forget the polarity protection series diode trick!)


FYI wrt some of your suppositions...
With few exceptions (eg CDI and a few HEIs etc), ignition systems are all 0V (aka GND, earth, chassis) switching akin to Open Collector outputs. (Shit eh, just like computers... I wonder why... :wink:)
Points connect the igCoil- to 0V else not.
Ignitors connect the igCoil- to 0V else not.

Ignitor inputs usually follow the above convention - ie, digital inputs whether from Hall or optical modules or ECUs are either 0V else not.
Hall & optical modules (sensors) include analog & waveshaping circuitry - or analog to digital conversion - and hence their ignitors are squarewave aka digital input.
Since reluctor systems are usually the raw reluctor sensor only (ie, magnetics with a sensor coil output), reluctor ignitors include the analog trigger circuitry which is almost always (by convention) triggered by the -ve going zero crossing of the reluctor's AC output.


More FYI... To convert reluctor to square, the old G200W twincam ignitor circuit (as shown in the G200WE-EngineManual.pdf) IMO is a great design... Its 2-transistor front end where one transistor is used as a bias-offset diode gives very close to 0V zero crossing (temp compensated too!!) and is easy to replicate. That is followed by whatever is needed for buffering and output inversion. (From memory, those 2 FE trannies are followed by a 3rd for signal inversion whilst the 4th & 5th provide the amplification needed for the IgCoil.)
And to convert a digital or squarewave for a reluctor ignitor requires a series cap plus a resistor or 2 and maybe an (inverting) transistor depending on signal polarities.
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Post by archangel62 » Thu May 08, 2014 10:06 am

Hey Peter! Thanks for the reply, I was hoping you might see this :cyclops:

The wires at my module all seem to be solid colours as pictured, rather than striped, however I will trace them back to the main loom, it's quite possible they change colours. It's bloody cold in the Adelaide hills at the moment, and dark when I get home, so I haven't had a look since the weekend.

From what you've said, it sounds like the tacho signal wire is the green one, that's about half of my problem solved, so that's a great start.

The uTech diagram suggests connecting the +ve side of the injectors directly to the battery [via 15A fuse, which also covers the ECU itself]. I wonder if there's any benefit to operating them via the relay too? I wonder what amperage the relay is good for?

I was going to take the Ignition +12V from the Piazza coil +ve, hopefully this is downstream of the reverse polarity diode, as well as whatever rollover protection the Piazza uses (perhaps charge?) but I could go straight to the source at the relay, it just means I have to trace it back and figure out which pin on the relay it uses :yawinkle: as I've had very minimal tinkering with relays.

It seems the knock sensor may not be so viable after all, unless I can figure out how it operates. The uTech has an "Aux In" line but I'm not sure what its I/O functions include. If it has as simple "on/off = ground/open" function (or switched +12V) then perhaps the uTech could be programmed to run a safer map if this occurs, but if it tries to moderate spark itself (ie pulse for the coil ground) then that might just confuse the uTech. Apparently each model engine block and microphone have to be calibrated carefully by the manufacturer to detect knock, so the uTech wouldn't be able to use a knock sensor in its own right (at least not my model). If only I could find more info on the knock system - although, I believe I finally have the full manual en route, which might help.
Indigo - '76 TX Gemini sedan, G180W+T project,
Abigail - '81 TE sedan, white, G180W ITB project,
New Hotness - TG Gemini drift car, orange, 4ZE1+T
Tardis - 1986 Piazza 4ZC1-T, black, forged, 136rwkw @13psi
Coupe - TX coupe grip car, "do it later", G180W+twin carbs
Trevor aka Jimmy's Gem - Grandpa-spec TD
BA Falcon - Tow car

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Post by IZU069 » Thu May 08, 2014 9:05 pm

Are you using the original (or other) Lo-Z impedance injectors? If so, they need the ballast resistors UNLESS the uTech drivers have current limiting.
But I was recently converted so hi-Z injectors of ~2007 and newer vintage. You may recall that I'd never touch hi-Zs for various reasons and would only use lo-Z tho probably newer manufacture. But as of ~2007 they overcame all the hi-Z limitations or problems that I had issues with.
So now I'd use modern hi-Z. (Tho I didn't investigate if a regulated voltage source was worthwhile...)

A few years back I looked at a few common modern hi-Z O-ring injectors for Piazza and G200W use (Poida was going to have fuel rails made for the G-W engines) but that too stalled. (Was it VY Commodore?)


The knock sensor should come after the uTech.
In principle it's easy - instead of feeding the reluctor coil signal to the KCU, feed the uTech ignition output (via a cap as mentioned in my last reply).
The KCU feeds the (new digital) ignitor.

I did intend to decipher the KCU circuitry. It should be simple enough to figure out the input to ascertain the tuned frequency. The rest shouldn't matter - it's probably easier using a PICAXE 08M2. (One input is uTech ignition pulse. Another is filtered knock sensor. One output is to the ignitor. Upon knock, the 08 merely adds delay(s) to the output pulse until knocking disappears and it resets after some period (a few seconds at most?).
[ Could use i2c output to signal messages or warnings, or an output to light a "knock LED". Flashing LED or other output if excessive knock detected - ie, retard the dizzy or reprogram the uTech curve. And it could even adjust per cylinder. Messages could be "x retards of max y mSecs at z RPM" etc. Not that I have built my 08M2 replacement for the Silicon Chip "Programmable Ignition" yet... ]


The relays should have ~20A to 30A contact rating but I'm not sure.
However they are obviously rated enough for old (high current) ECUs and lo-Z injectors.
I would generally only trigger a relay (coil) from igCoil +12V to switch battery +12V to the load rather than noisy (and probably reduced) +12V from igCoil +12V.

FYI - Nothing is "downstream" of any diode. The diode is in the relay's coil circuit - it is not in the power path. Hence a mere 1N400x diode, and there is no diode voltage drop in the power feed.


You do have a copy of PiazzaManual.PDF don't you? Its Section 12 is invaluable (though one wiring diagram page is missing).
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Post by Bugle » Thu May 08, 2014 11:52 pm

The black wire is tacho, it comes off the coil neg and splits off into two connections to the wiring harness. One is for the boost control computer & ECU, the other is for the tacho.

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Post by archangel62 » Fri May 09, 2014 12:49 pm

Thanks again for the added info! I actually just got the Piazza manual yesterday! I tried a few years ago but something went amiss and it fell in the too-hard-basket. But I spent last night pilfering through it and found some handy stuff. I've updated my original post label legend to reflect my current understanding.

Tacho wire: Bugle, cheers, I went outside last night at some ridiculous hour with a torch, no doubt perplexed my neighbours and confirmed that the black wire passes through a single pin connector and becomes black/red before heading to the tachometer, so I'll connect it to that :D

Injector impedance: Peter, cheers again. I'm using non-original low-Z injectors (they're actually off of a Merc, hose-tail, rated at 380cc but flowed 420cc @3bar if memory serves). The Microtech can handle the low impedance injectors without ballast - although with ballast is fine too. Is there any benefit of running ballast resistors if the ECU can handle either? I see the Piazza wiring has ballast resistors after the main relay but before the injectors for the factory ECU. If there's no benefit, I might just pull power directly from the main relay instead to keep the Microtech wiring simple.

Ignition +12V: just a quick sidenote, I've noticed the Piazza supplies the coil's power direct from the ignition switch (ie key barrel) I believe. There's no relay for the coil. Hopefully the uTech doesn't add too much current; presumably the new ign coil has similar draw (impedance was similar IIRC). I'm not sure if the Piazza's Main Relay has the same function, but I might try to power the uTech's "ignition switch" from the coil/barrel - the uTech has a separate +12V main supply which I will take directly from the battery via a new fused wire - does this sound good?

Knock Control Unit stuff: this is non-essential for the first start, tune etc, so less urgent, but it'd be nice to nut it out before I fit conduits etc. I guess I could just get the car tuned without any of this, and then [afterwards] try re-routing the uTech's tacho/module trigger output via the wires marked as White and Red on the diagrams between Igniter and KCU - but I don't know which way around, or if that matters. Also, this seems strange as White and Red are also the colours used from the reluctor to the ignition module. Surely the KCU doesn't modify the bare reluctor signal? Maybe the colours are up the creek and it actually operates on the wires which are Green and Blue at the module, which share a plug, and change colours to Red-ish and Yellow-ish after the plugs (to be confirmed, they're grubby).

Here's a bit of an info dump/brainstorm... you don't have to read it, but it's the reason for my confusion and reasoning.

The best diagrams I've found are on pages 870 and 871, though there's also some info on pages 787, 659, 644. I can see that the KCU has two wires, White, and Red, to the ignition module. One is an input, one is an output. There is also a wire from the KCU labelled "Ground igniter". I'm not sure if this is providing a ground for the igniter via the KCU, or grounding the KCU to the igniter (though the KCU has its own ground). Or, I'm not sure if this is switched to completely kill spark for major knock (but I doubt it, it sounds like it just retards up to 10deg of ign timing). The KCU also grounds via the Vacuum Switch, I'm not sure if this is to adjust the VS under knock condition, or if it's to gain input from the VS (doubtful; I think the VS is a control unit, not a sender). The KCU also connects to the Turbo Control System (TCS) using two wires.

Now, looking at the Igniter on pg 871, the two wires that go to/from the KCU have some circuitry inside the Igniter itself, which gives me some concern (probably unfounded) that the KCU isn't a pure and self-sufficient circuit to modify the -ve switch upstream of the actual Igniter switching component. I don't understand what the diagram is trying to convey inside the Igniter because it isn't very clear, I think the bottom bit is the reluctor in the distributor. It almost looks like the KCU is in parallel to something. They mark "From KCU" from what appears to be the Reluctor as #4 (White) and the "To KCU" from what seems to be the actual Igniter switch as #10 (Red), which seems backwards to my logic (and why are the two points bridged by that wire, thus bypassing the KCU anyway?? surely this is just poor drawing?) so I mustn't be reading it right!

I wonder if the KCU would trigger the "check engine" light... Also, for the sake of testing (and an implication to its function), Page 659 suggests that if the knock sensor is working, you can disconnect it at over 1600rpm and the ignition timing should retard by about 10 degrees. It also mentions disconnecting the vacuum switch to do this, but I think that's just to prevent interference in the test.

If you read all that I owe you a cookie.

More happy snaps:

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Indigo - '76 TX Gemini sedan, G180W+T project,
Abigail - '81 TE sedan, white, G180W ITB project,
New Hotness - TG Gemini drift car, orange, 4ZE1+T
Tardis - 1986 Piazza 4ZC1-T, black, forged, 136rwkw @13psi
Coupe - TX coupe grip car, "do it later", G180W+twin carbs
Trevor aka Jimmy's Gem - Grandpa-spec TD
BA Falcon - Tow car

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Post by IZU069 » Fri May 09, 2014 8:32 pm

archangel62 wrote:... to reflect my current understanding.
Hey man, I hope you understand voltage too!
(Doesn't voltage cum before current (as far as we are concerned) - hence voltage is male and the most important? !!)

Hey Eli - pathetic I know, but IMO it's been far too long between cracks - I mean jokes - on forums. (Read: I'm leaving another one!)

And I agree - thanks Bugle!


Now I recall something about PDF problems...
Tho I reckon most of it you don't need, IMHO section 12 (Electricals) is essential. That's followed by section 12, and of course Electricals, and pages 733 to 874... that's in order of importance (IMHO). Yes, it's been far too long......
I'm sure there are other important or handy sections - I just can't recall them atm.

FYI - I think the Isuzu standard was B/R (Black/Red) for tacho/points with BY (Black/Yellow) for igCoil +12V (or IGN +12V) but I do recall an issue of inversion (or was it confusion?) when dealing with RB ignitors (ie, for the "universal G-series engine" RG electronic distributor). But maybe that was a Bellett/Florian issue...

But the latter - like whatever else I am about to write or did write - can be confirmed. Apart from those PDF page numbers, I'm really running from memory.


Injectors:
Like I said, modern hi-Z injectors are the way to go. That means the more convenient O-ring seals (ain't those Piazza injector hoses a shit to remove etc?) at the expense of new fuel rails. And lower current drivers.
[ At least you are upgrading and tuning the uTech. I used to laugh at those elsewhere (eg, OzGem) that would merely upsize injectors thinking that would somehow improve performance. For an open system akin to carbies maybe yes, but not a typical closed-loop EFI system! ]

If uTech state that it handles lo-Z injectors AND that ballasts are not required, then I'd omit the ballast. It's a few less points of failure.
Obviously they therefore have ONE driver per injector as opposed to one driver per pair or batch of injectors as per the Aussie non-ITEC Piazza.
If they drive 2 or more injectors off the same driver (terminal) - then stop and investigate - there is something wrong with their information (read: you will probably burn out the other injector(s) if one circuit goes open etc).

All ballasted injectors I know of have the ballast on their +12V side because - just like igCoils - they are almost always ground switched. (Remember the Open-Collector outputs I mentioned?)
It's much easier with a 5-terminal 4-resistor ballast pack than an 8-terminal pack. IE - one common terminal (+12V) with 4 outputs from each resistors as opposed to 4 resistors each with an input and output if places between each injector and its switching circuit (the EMS injector driver).
BTW - (as I recall...) although the OEM non-ITEC Piazza has two injector drivers each driving 2 injectors, I think they are all fired together. Alas it's detail like that that does influence new-EMS injector sizing. In simple principle, a sequentially fired injector needs to be 4-times the size of a batch fired injector (for a 4-cyl engine), however it's not that simple - ie, in practice many sequentials can use the same batch injectors. Injector sizing issues for guys like us is usually whether the engine will idle cleanly - ie, are the injectors too big?. [I could mention my Guru that had dual-injectors (per cylinder) on his G180W...]


I'd be powering injectors thru a relay. In part that's to limit the number of live or hot circuits around the vehicle - especially the engine bay in case of fire or overheating - but also because driver components can leak, or fail in lo-Z or short-circuit mode and hence burning out injectors or flattening the battery, and fail due to reversed battery polarity.
I suspect that is why Masters like Isuzu and other Japs also relay-switch their injectors. (With polarity protection of course!)

Ah - see PiazzaManual p792 = p12-58 Power Source NO.2 "Relay; Main" (from top left - 2 relays across, then 1 relay down)...
You'll see it is two SPST relay contacts off a single coil. The grounded coil is energised by the IGN switch. (I don't know how & don't care but I know I trust that label info because I have traced it in years past. And the relevant info will be on another page, but as you can tell, I like short replies - I don't have time to fck around or asquare with trivial details that I know are trivial despite their correctness and my approval.)

From that Relay; Main's terminal labels 1C. 3C, 2C, 4C - ie connector "C" terminals 1 to 4 - and then looking below the circuit diagram and finding the A, B - aha! - C connector pic, you'll see what the connector looks like. It confirms it's "Relay; main" and the BROWN means it's a brown relay.
[ Good, now I don't have to find out if it was the brown or grey type of (JIDEC or JECS?) relay that I wasn't sure about in a previous reply. That means the GREY relay is the "changeover-inversion" type as typically used for aircons - ie, if the starter is enabled, the aircon clutch is not. Now that rings 2 bells - firstly an old thread somewhere about someone that did not understand grey relay functioning (and hence blew whatever....), and 2ndly how I used to hate those non-Bosch/Hella relays (ie, those funnily based JIDEC types) until I loved them; their brilliance; their relative reliability; and how all JIDEC type blue SPSTs are now all black type SPDTs (yay!) ]
And it shows the relay-base position of each of the circuit diagram connections shown above.

Usually all Isuzu circuit diagrams show the colour codes. IE - you can see the that MIAN relay's two WL = White/bLue flinked +12V inputs and WG White/Green & WB White Black outputs to the Engine Computer.

FYI - p870 shows that WG is to the injector ballast (and engine check light) & WB becomes R Red to power the ECU (#24).
[Unlike other vehicles it is rare for Jap or Isuzu vehicles to change wire colors mid harness, however as their circuit diagrams show, they might do it. But at least Isuzu (and Japs in general) document it - unlike others (not to mention Europeans!) that seem to do it randomly and as a matter of course. To think several Jap auto manufacturers conform to the same or similar color-coding conventions...]

And on p870 you'll see the reverse polarity protection diode I was talking about to the left of the RELAY; main. As you (should or might) know, current can only travel in the direction of the arrow thru a diode symbol. Hence only if the "E" feed (BY = Black Yellow) feed from the IGN position of the IgSwitch is +ve wrt to the lower "buss" line "a" will that main relay energise. Hence the battery must be connected with the correct polarity. [BTW - all lower buss-lines are grounds (=GND = chassis = earth = battery -ve = 0V etc). But they are shown separately depending on where those (buss) wires are grounded. That becomes important when fault finding electrical & sensor issues.]

But stop distracting me. You know I hate long replies. It's not as if I post anything educational. And even if I do, it gets lost in excessive verbiage.


In fact, I'll punctuate this here. I need to open another gin - two Gordon's 700ml for $61.90 at Dan Murphy's. That'll keep me until my $3 Chardonnays cool down.
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Post by IZU069 » Fri May 09, 2014 10:38 pm

Knock sensing...
AFIAC, no engine should ever be tuned with the knock sensor operational. The knock sensor is a protection device when tuning is incorrect - eg, lower octane fuel, carbonised combustion chambers & pistons, excess turbo boost, mapping & sensor errors, etc.

Despite what someone once said on OzFemini, I assume the old Chrysler "advance until knock" tuning systems are no longer used. It might be used on occasion for self tuning or after a fuel refill - I'm talking about a consistent advance-till-knock ignition method. Note however that that I base that on info from electronic magazine automotive designers and my own understanding - reality may be different. (If so, do they know something "we" don't, or are they yet to comprehend?)

Anyhow, your engine can (and should) be tuned without engine knock retards active.
Hence you can add the KCU later. That assumes the KCU in circuit but that without the knock sensor does NOT mean any delay, but I see no reason that it should. (Hey man, even if a few hundred CPU cycles, that's nothing compared to engine ignition!) POST EDIT - this is subject to p659 interpretation far below.
So I/we have time to figure out KCU operation. And IMO only its input & output waveshapes and polarity need clarification... So what if we don't know how much it retards and when it resets - IMO as long as it stops knocking (which should never occur...) and hence prevents engine damage...


You mentioned pages 870 & 871. (Now where did I mention those (hic) - they ring a bell...)
I agree, they seem to be the best.
And have you noted how I said Isuzu/Jap diagrams are GREAT because they include color codes? Ok, so there are exceptions. Of course they only exist when critical. (Like details in old Microsoft or Apple/Macintosh documentation - tho FAR less obvious!)
Note how exceptions are only noted when you finally drill into detail...
(Notice how no one has ever mentioned the missing sections 10 - 14 after p12-135 (PiazzaManual.PDF p869). They should be PDF page 872 and cover Hazard Warning; Back-up lamp; Room Lamp; Headlight & headlight cover; & Illumination. It took me years to notice that!)

So yeah, atm I am at a loss as to the actual colors and interconnections. However I'm certain I once had a handle on that, and noted else documented that. But that's another story. And it's too dark and cold to go out now and trace...


As to MY interpretation of reluctor & ignitor & KCU operation which is based on the ignitor schematic on PDF p871 and RB ignitor stuff - eg, where the reluctor sensor coil has its red or brown (+) and white or grey (-) output wires...
The sensor coil feeds the -ve going zero-crossing detector - ie, the lower rectangular block in the IGNITOR.
That zero-crossing block feeds:
- the upper block, &
- the KCU... Oh shit... "FROM the KCU (#4)" - I assumed TO the KCU... OK, bear with me.

I assumed the upper block with "TO the KCU (#10)" was FROM the KCU and was the smarts to add a delay to the lower block normal timing trigger signal before passing on to the igCoil driver (the upper transistor).
That's what I was describing in whatever earlier reply.

Maybe the TO and FROM KCU labels are wrong. Of course Isuzu would NEVER get that wrong (tho at times they fkup), but this is GMH documentation...


RIGHT - now I mean business! I've loaded up my $2 2L K-Mart glass (LOL - they called it a vase!) - that 250ml tumbler was just too small. Hopefully that gin will keep until the wine is chilled enough.
And I'm thinking aloud. Or rather, in type....

BTW - this is all irrelevant for now, but fk ya, YOU started this so you deserve to suffer too. I'm old and have zero tolerance.
Actually I'm old and still have lots of tolerance (Dog knows why!) but have infinite vengeance once triggered.


So if the the wave shaper (reluctor zero detector) gets the KCU output, that means it has a delay feed.
So the delayed (engine knocking) signal is passed to the upper block (and igCoil switching), and that goes to KCU input... why?
Confirm the delay duration? (No, the KCU knows the delay it sent.)
Revoke the delay? (No, the KCU's microphone confirms no knock and hence holds else reduced or removes the delay from its output.)
I had another thought, but 7mate's "The Adjustment Bureau" robbed that.

I'll bail out and recite some wise statement about mere semantics... "this is all irrelevant for now". Whatever wiseguy said that may have some unfking to do.
And I'll pre-empt something I expected to say later - if or when I decipher (reverse-engineer) the KCU module's circuitry...".


Re the "ground ignitor", I suspect that's the OC (Open Collector) aka GND-switched signal to the ignitor - ie, the typical signal to trigger any ignitor whether it be points, Hall or optic modules, etc (noting the odd exception).

But note that the KCU should never prevent a spark - ie, it would not keep its output grounded (or whatever polarity) to prevent a spark - it will merely delay spark. The igCoil must be released at some stage (and hence spark) tho I guess it could be delayed for a full cycle (ie, next half 4-cyl engine crank rotation's compression) but why - that doesn't make sense(?). And I admit I was confusing a bit with cutting fuel or injection which means a lean ignition which can be VERY damaging.
If the KCI can't delay enough, I'd assume a "check engine" light/alarm else and engine cut - tho engine cuts are rarely implemented. (EG - even for no oil pressure , OEM engines are never cut. It's left to the driver to decide if they want to kill the engine or drive on. Of course with that I exclude idiots that control electric fuel pumps using oil pressure, and non-OEM or performance engines (dragsters etc) where engine damage prevention is all important and driver/passenger safety is irrelevant else less important.)


And now I read your p659 stuff...
BTW - I agree with your analysis (except my IMOs above). Strictly speaking I should say "I don't disagree". I really mean that your interpretation is consistent with mine - UNTIL you or I find otherwise - ie, until we find more info, whether thru Bugle, or the PDF, or my KCU deciphering, etc etc.

But atm I interpret p659 as meaning that the KCU subtracts from some inbuilt Piazza ignitor retard delay. Tho that fits in well with my previously bailed out discussion, I see it as questionable. IE - it means the KCU must be present for normally acceptable operation (ie, NOT retarded by 10 degrees which would mean overheating and possible damage, plus poor performance). Then again, to ensure no damage from pre-detonation (knocking), it makes sense.
I can certainly understand the latter being a priority. (Isuzu build bullet proof engines...)

Oddly enough this reminds me of yTF we got landed in 1986 with the recalcitrant licenced Bosch jetronic fuel-only ECU when Piazzas had the all-electronic G200W I-TEC fuel & ignition (using "our" 1989 onward 4ZE1 locked optical distributors) back in 1980 and elsewhere 4ZC1-ts also used I-TEC.
(LOL - that discussion was my final straw that caused me to abandon bellett.net. In retrospect that was a blessing - the amount of crap and misinformation I have seen there since. I pity those sucked in by the misinformation and expensive (non?) fixes. But I guess the litols and money makers are happy as pigs in shit.)


Speaking of which - you are in a bad situation. How dare You cause me to try to recollect old learnings let alone probably complete stuff which I no longer have any use for (KCU rev-engineering etc).
You Doggamed pie-floating Sauzzie - just wait till I get over there again - you WILL be visited. And it'll be a farken beer - not a farken cookie which my PC deletes automatically (after a delay of course!!). (Your last reply 2nd last line refers.)

Yours VERY sincerely - until I sober up. (Hey man, I need a 4L K-Mart vase!)

Peter.


(PS - I just noted I'm a power moderator hereon. Oh it's been way far too long! Glad I'm leaving another forum. That leaves 4 - 3 of which are Isuzu.)
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Post by archangel62 » Tue May 13, 2014 12:26 am

Hey again! Sorry for the slow reply. I read your posts on Saturday night but didn't have time to write a decent response.

I've sourced the Microtech's main +12V from the old injector output on the "Main" relay. I'm hoping that this will be on at all times that the ignition is "On", but also come with the benefit of having a diode in the relay for reversed polarity protection. I figure that output had the lowest amperage drain since the old injector bank isn't doing anything - but I didn't cut the original wire, it merely isn't connected to the injectors anymore on the big green inlet loom plug.

I have, however, sourced the new injectors' power supply directly from the battery via a fuse in a little clip/box which I piggybacked on an existing bolt for the injector blower hose. This is because I didn't want the un-resisted injector current leeching off of a factory circuit that probably isn't designed for it.

The coil positive feed as well as Microtech ignition +12V has been sourced from the Piazza's original coil positive clip, located right near the back corner of the engine bay. I used a slip-on tab which was fairly tight, and some tape, but later on I might buy a spare Piazza ignition module and cut the clips off, so I can use them instead for that extra solid, factory feel. As always, I won't damage my original parts, in the interests of owning a complete original system.

The tacho, ECGI and TCS units are all receiving their coil negative signal as per factory, but using the new coil and module.

The discussion of the KCU is very helpful, I've set it aside just for the moment though, while I get the last few things nutted out. I have 2.5 weeks to have the car completely ready for the tuner - it's all booked in!

My next question is a lot simpler. I'm slightly concerned about reluctor polarity and shielding. Not super concerned, just a little. The Piazza reluctor output has a red wire and a beige wire. The Microtech has a red wire and a blue wire. I'm fairly sure I should just connect red to red, and beige to blue? I figure if I get them wrong, the worst that can happen is it will mess with the base timing a little bit, but I'd still prefer to get it right. Also, the Microtech has a shielded wire but it only just reaches the engine bay before it's been cut. The Piazza's reluctor wires aren't shielded and I was just going to extend them, since I don't have any shielded wire handy. Is it essential or beneficial to shield these? Are they likely to suffer from interference that could cause a bad reading or a miss? Could I make my own shielding by removing the insulation on some wire and spreading it around the reluctor wires, then earthing at one end?

Anyway, in other news, I killed 54 mosquitoes with my bare hands on Sunday whilst wiring stuff. I've got it down to a fine art. I was pretty chuffed with that. Glad to hear you're on the inspiration sauce, wish I had time for a few but I'm saving them til victory. I also have to have my TE Gemini's side windows in by Friday if possible, I'm having a trimmer out to do the roof lining on Saturday and it's been raining a lot lately. The front and rear screens will have to go in on Monday, so glad wrap may be in order... Busy times. Hopefully in three weeks I'll be knocking back a few cold ones over a slain to-do list. But the damn thing just keeps respawning...
Indigo - '76 TX Gemini sedan, G180W+T project,
Abigail - '81 TE sedan, white, G180W ITB project,
New Hotness - TG Gemini drift car, orange, 4ZE1+T
Tardis - 1986 Piazza 4ZC1-T, black, forged, 136rwkw @13psi
Coupe - TX coupe grip car, "do it later", G180W+twin carbs
Trevor aka Jimmy's Gem - Grandpa-spec TD
BA Falcon - Tow car

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Post by IZU069 » Tue May 13, 2014 8:52 am

Man, get one of those bug-zapping tennis raquets - the best thing since Piazzas were released.
They keep you fit; are lots of fun; bring a smile at each zap; chemical free and kinder to victims (**)...
Leave one beside the bed for lamp-free destruction of those pesky lights-out mozzies without the need to open an eye.

** except maybe cockroaches and european wasps, however some consider their ongoing torture pleasurable. Weak zappers that may allow escapes - especially of angered euro wasps - can be safety enhanced by adding another capacitor. (Keep any old or broken zappers for capacitor salvaging - their caps are HIGH voltage types that can be hard to otherwise obtain.)

FTR - this author drives a Japanese Wasp (and no raquet or zap will have any effect on that!).



Otherwise things sound good.
I agree with a non-cutting approach to electrics. I always interface with adaptors else single connectors, or bypass altogether. Tho I have ~1985 Jackaroo dash and steering combi switch & 1990 Hitachi/Mitsubish alternator & headlight relays etc etc, my 1965 Wasp can be returned to OEM wiring in minutes.


You're pretty correct with the reluctor wiring. I'd also assume red is red. (Even in AC wiring red is now brown (touch it & you'll shit yourself) and NOT blue.)

Getting the polarity wrong is not destructive to the reluctor etc - the polarity signifies phasing as for speakers as opposed to potentially destructive electrical polarity.

But getting polarity wrong will have MAJOR effects on the engine. Usually the engine will retard rather than advance with increasing RPM (... as I recall - all that analysis was ages ago!).

And don't worry about shielding - that's for those inferior Camira & N13 etc old generation reluctor systems (like the Isuzu twincams had). That went out along with the need to use non-magnetic feeler gauges.
Shielding might be required if the signal runs close to a big switcher like splugs or (maybe?) injectors.


BTW - the Piazza "Main" aka IGN relay powers both ECU & injectors (one output each) so why not use the old ECU output for the injectors? I'm thinking that AFAIR, injectors are (IGN) relay powered and not direct to +12V battery....
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Post by archangel62 » Tue May 13, 2014 11:48 am

Hahaha yeah those racquets are great fun. Do they still hit mozzies? I would have thought they'd be too small, and I've only tried on big stupid blowflies. I saw an instructional video for a redneck mozzie zapper that looks the goods - get a box fan, tightly fix fly screen to the exit-side, leave it on for hours and the mozzies get trapped in the screen, then use a mist bottle to spray diluted metho into it, killing all the trapped little jerks. The redneck in the video said he'd kill over 500 per night with the thing running, and it was enough to significantly reduce the mozzie population in the whole area! He actually left out the dead mozzies for local wildlife to eat too. But frankly I just want to not be swimming in the damn things.

Anyway, I digress.

As to the new injector feed, I didn't want to run them from either of the "Main" relay outputs since they'd draw a higher amperage than the original injector+resistor pack setup. It'd probably be fine, but nevertheless. Plus, the old ECU output from the main relay is still in use (ECGI will still be "on", it just won't do much). I just hope that running the Microtech off of the "Main" relay won't turn it off prematurely. They did call for it to be straight to the battery, but I ditched that in favour of the protection circuit. Maybe I should have hooked it up to the Ignition switch instead. The coil +12V tells the Microtech when to turn on anyway. Perhaps it still needs the constant to save data logging etc after the engine is turned off. But this will come back to the old "if it causes issues, I'll fix it later" rule. At least it's run to the relay box anyway.

Reluctor stuff makes sense - I figured that out of phase would mean putting the timing out, but I didn't realise that it could dynamically alter things throughout the rev range. Hopefully red to red sorts it out anyway, and I'll tell the tuner "if it does strange things, let me know". I'm going to attempt a quick start on the G180W's old map (for what I'd guess are smaller injectors, too). It'll run like a sack of potatoes, but if it fires and the timing is what I'm expecting it to be, then that's one less stress. Plus, it would suggest that the rest of this crazy endeavour had been a success.

Glad to hear about the shielding. It will be run in the same conduit as the injector ground wires and the rest of the Microtech loom, but nowhere near HT leads or anything like that. At least "most" of the reluctor wiring is shielded - it's just the last 50cm or so in the engine bay that won't be.

Here's some happy snaps from Sunday night:

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Indigo - '76 TX Gemini sedan, G180W+T project,
Abigail - '81 TE sedan, white, G180W ITB project,
New Hotness - TG Gemini drift car, orange, 4ZE1+T
Tardis - 1986 Piazza 4ZC1-T, black, forged, 136rwkw @13psi
Coupe - TX coupe grip car, "do it later", G180W+twin carbs
Trevor aka Jimmy's Gem - Grandpa-spec TD
BA Falcon - Tow car

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Post by IZU069 » Tue May 13, 2014 1:55 pm

The new injectors shouldn't draw significantly more current than the OEM even without ballasts. That assumes the uTech does current limit, but if it doesn't the new injectors will soon blow and in that case it's better to leave on the old flinked relay. (From memory it has its own flink, and if that was sized for its ECU & injectors plus a bit more, it's a good first test. Of course it may be over-linked (over-sized) to protect against shorts as opposed to "equipment" or load protection...)

I don't see the need to run the old ECU. From memory it does nothing other than the fuel but you might know (or I might later find) something additional.
Plus I assumed the (new?) uTech sensors would be in place of the old else using the originals in which case the orig ECU probably should not be connected, but if you have parallel plumbed (fitted new thermal etc sensors), the old ECU could remain.


Just checking, but I'd assume their "straight from the battery" means via a relay with a new (and fused!!) power feed - ie, the usual PC or audio "getting the cleanest 12V" practice. I doubt it literally means a permanent +12V connection UNLESS it's like an amp with a remote on (ie, the low current remote +12V turns on a relay in the amp that connects raw fused battery +12V).


Some spiral or split corrugated conduit should cover your loose loom nicely.
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Post by IZU069 » Tue May 13, 2014 6:18 pm

PS - From another forum I was recently informed that duct take conducts (electricity) - so beware!
I've never used it for insulation so I don't know...

And yet again I think of the situation with those old wire-type flinks.
Firstly, I was amazed that they were so specifically sized - eg, instead of 10A, 15A, 20A, 25A, 30A, 40A etc they were 13A, 16A, 21A, 26A etc.
Secondly, they are a smoke and fire hazard themselves.
Thirdly, in response to an old (IMO) due diligence agreement with someone here on IsuPiazza (Wedgy?) that warned or stated that BIGGER fuses or flinks should NOT be substituted, upon investigation I found that (at least?) one of the Piazza flinked wires is rated less than the flink, and the others were capable of higher.

Re the latter, in practice to my knowledge no Piazza has ever flamed due to such a wire under-sizing, yet I assume the relevant flink has blown on many occasions. (Then again, Jap wiring is usually so good...)
And wire ratings are somewhat subjective. The same wire may have different ratings depending on whether it is chassis wiring (bundled or heat-sunk) or transmission wiring (on its own?). I found some tables are ratings based on acceptable voltage drops and NOT safety (ie, maximum current before fusing or insulation degradation).
Some are at specific temperatures - typically 25C compared to their lower ratings at engine bay temps though many may assume up to 110C etc

And most ratings are for long runs. IE - a short "10A" cable carrying (say) 12A may be fine if its ends suitably conduct heat away.
Plus there is often safety margin - eg, assume insulation or conductivity degradation of 20% or 33% etc.


Anyhow, I digressed...
The point is that ages ago I was considering a Piazza (& Gemini) upgrade from wire flinks to modern plastic type.
As it turns out, based on Amperage alone, normal blade fuses are probably suitable - eg, use the next lowest sized blade fuse instead of the flink. (Normal blades go up to 30A hence covering our flinks. There are higher rated wire flinks but "we" don't use them.)
Originally I was considering an equivalent battery post setup eg:
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... but if ordinary blade fuses are ok.
But I'll have to investigate the clearing (blow) times of flinks versus fuses.
Otherwise I thought that pictured +12V battery terminal flink box was an ideal replacement for the 3 OEM Piazza wire flinks.
There is a 4th flink somewhere, and from memory IMO it was not wired in the best position - ie, it was in series with others instead of parallel; any master series fuse/flink should be an absolute last-resort blower that only blows given catastrophic failure, ie, not just mere overloads from other flinks or circuits. [That assumes it isn't a source protector like alternator or battery protector, but our alternators are not fused/protected from overload (the fuse should be on the battery end), and you don't often see 300A or 400A etc fuses protecting batteries - except perhaps those with non-lead terminals.]

Nowadays there are also the mini (or micro) flinks as well as micro-ATS fuses. (I'll probably used those along with micro-DIN relays for my Wasp rewiring if I ever get to do that!)

And critical circuits like lighting should use auto-resetting circuit breakers (under $10 for ATS blade and mini-blade fuses).
[ I should consult my notes to get the correct name for ATC - or are they ATC - and mini or micro fuses & relays etc... ]


And my apologies, I lost track of my intended target thanks to a long phone call somewhere during the above writing. [I've just resigned from my voluntary OpShop shifts. I thought it was bound to cause a stir! (LOL - :evilsmile:) ]


I did want to say that main feed wiring upgrades (from OEM flinks to relay & fuseboxes etc) may not be necessary even for a flink rating upsize. I did start that dimensioning investigation years ago...
Alternatively it may be simple bypassing the OEM wiring with new stuff - maybe with s suitable flink (and fuse & relay?) box mounted on the engine bay.
(Reminds me of the Gemini alternator upgrades. Forget modifying the OEM regulator to alternator wiring. It is much easier running the alternator's L output direct to the (removed) old regulator's white-red position (whether thru a 6-pin male spade connector or a single male spade), and a new wire from the alternator's S (Sense) terminal direct to the +12V battery terminal (whether an unfused thin wire, or a fuse thicker wire). If the alternator also as an I = Ig = IGN terminal (which is not that common), it to can be run to the original regulator's connector (ie, male spade; it might be the white wire?).
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Post by archangel62 » Mon Jun 02, 2014 12:03 pm

Howdy again, sorry for the radio silence, it's been a crazy... however long. Absolute rush getting everything ready in time. I'm just going to pose a quick question before I get sidetracked:

- Oil pressure warning light is now flashing once started. It has oil in it, it sounds fine, and I haven't touched anything that would cause problems with oil pressure. However, the wiring has of course been tampered with. I'm pretty damn sure it should be fine, but I just want to check - if oil pressure takes longer to build after starting than normal, will the oil light continue to flash, even once there's pressure?

Anyway, the car is now at Jaustech for piping and a tune. There was a slight incident with the trailer coming un-hitched in a service station and being dragged by the chains, but we're alright and there was no damage. The Piazza/s wiring is of course done, wrapped in tape (it's okay, everything was heat-shrink insulated anyway), put in a conduit, and then wrapped in tape again. exits from the conduit are run through vac hose to prevent wire damage. The vac hoses on the motor have been re-jigged, the MAP signal is tee'd to the source in the plenum just next to the throttle body, that points towards the turbo/etc. I hope it's a good enough signal and that the T-pieces don't cause problems. The car starts and runs like absolute crap, being that the ECU was last mapped for a G180W with injectors half this size.

I left the injectors wired "directly" to the battery via a fuse mounted right next to it, but I checked for power leak and there's none. As for noise, I hadn't factored that in but I'd "hope" it wouldn't be too bad since it's right from the terminal. In other news, the battery (which is probably just under two years old) is cactus, but that's what I get for leaving it sitting. Bah.

Regarding sensors, I've added a coolant temp sender for the Microtech whilst running all of the originals, TPS is Microtech only with none for the old ECU, likewise o2. Inlet air temp I've fitted one for the Microtech just before the throttle body to avoid heat soak from the manifold, I'm not sure if the Piazza had one. AFM is gone altogether, knock sensor still connected but obviously KCU isn't attached to anything. I might try switching off the old ECU once all is said and done and see if it makes any difference - but I was worried the old ECU may control things like cruise control, or the dash, and just generally didn't want to mess with it.

I've sucked it up and made my Piazza album on my BookFace public, because picture hosting is a pain in the a**, so updated pics are there, but if the cbf's recede, I may upload pics too :P

https://www.facebook.com/eli.duykers/me ... 902&type=3

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Indigo - '76 TX Gemini sedan, G180W+T project,
Abigail - '81 TE sedan, white, G180W ITB project,
New Hotness - TG Gemini drift car, orange, 4ZE1+T
Tardis - 1986 Piazza 4ZC1-T, black, forged, 136rwkw @13psi
Coupe - TX coupe grip car, "do it later", G180W+twin carbs
Trevor aka Jimmy's Gem - Grandpa-spec TD
BA Falcon - Tow car

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Post by IZU069 » Mon Jun 02, 2014 2:26 pm

The cruise control etc should be separate. Our Piazza ECU is a licensed copy of the (IMO) primitive Bosch Jetronic or similar. It's a fuel only heap of shit that usually doesn't even control the fuel pump (the Germans usually leave that to their tachometric relays - a leftover from the days of carburettors).

I'd rig a separate oil gauge to check your oil pressure. It could be a faulty switch, or circuit, but you don't want low oil pressure.
Switches usually don't trigger until pressure drops below a few psi whereas the oil pressure should be far higher - eg, 35-45psi.


One of my oil pressure lights recently faulted as usual in its typical "not blocked" internal short mode. Hence my oil light was often shorted on.
But I've been running parallel oil pressure switches for years both for redundancy and as a way of lessening my older "40 seconds to turn on" after a warm engine stop, so I have merely disconnected the faulty switch.
IZU069 - ISUZU means a lot to me.

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