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.
IZU069 - ISUZU means a lot to me.