Isuzu Piazza JR120 - Engine doesn't run right...

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Piazzish
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Isuzu Piazza JR120 - Engine doesn't run right...

Post by Piazzish »

About three months ago I bought another piazza. I got it cheap because of it's condition. It looks like crap right now, but it isn't long away from being a good running car. I'm not comfortable to drive it when the engine runs like this..
The car is bought for parts/track days/ or just fun driving on ice at the winter.

The speedometer shows "CHECK ENGINE".

so mabye some of you can help me a little on the way.. The car drives, but the engine runs bad.. Not shure what the problem is yet...
Anyways I posted a video of it running. The first clip is the time when it ran at it's best.

http://www.youtube.com/watch?v=DIz0Q1T01yk

Thank you soo much for all help!
Last edited by Piazzish on Wed Aug 07, 2013 12:54 am, edited 1 time in total.
1989 Isuzu Piazza JR120 Lotus Turbo Red 92000km
1989 Isuzu Piazza JR120 Lotus Turbo White 183000km
1987 Isuzu Piazza JR120 Pre-Lotus Turbo Red 131000km
1984 Isuzu Piazza JR130 N/A Two-tone 145000km
1984 Isuzu Piazza JR130 N/A Black 92000km
1989 Isuzu Gemini JT190 Red 173000km
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vinnie55
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Post by vinnie55 »

I'm no mechanic. but it's time for a rebuild in any case. That much smoke could mean the rings are fucked and that noise could be a lower end bearing?
The more you run it the worse it'll get.
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wedgenut
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Post by wedgenut »

It could be a million things so you need to start some diagnosis by eliminating the the simple things.
It sounds like it is not running on all four, so first thing to do is Compression check, spark plug condition, leads, air cleaner and AFM. look for and fix any split vacuum hoses etc. The mechanical knocking is a worry.
So many cars, so little cash
IZU069
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Post by IZU069 »

Wedgenut x2.

The engine might be fine but with bad timing (faulty knock sensor) and faulty plugs.
Or it may be turbo.

Bu you could pay thousands of Kroner just to find the knock-sensor wire fell off with overly advanced timing or a broken distributor spring.
IZU069 - ISUZU means a lot to me.
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Piazzish
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Post by Piazzish »

Late update, but Thanks all for your help, the engine now runs fine!
http://www.youtube.com/watch?v=Iq5ikQMguY8
1989 Isuzu Piazza JR120 Lotus Turbo Red 92000km
1989 Isuzu Piazza JR120 Lotus Turbo White 183000km
1987 Isuzu Piazza JR120 Pre-Lotus Turbo Red 131000km
1984 Isuzu Piazza JR130 N/A Two-tone 145000km
1984 Isuzu Piazza JR130 N/A Black 92000km
1989 Isuzu Gemini JT190 Red 173000km
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Piazza_man
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Post by Piazza_man »

That's great that you have it running properly. What was wrong with it and how did you fix it?
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Piazzish
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Post by Piazzish »

The Air Flow Sensor was faulty... Just tried with the one on the white piazza, And it worked!
1989 Isuzu Piazza JR120 Lotus Turbo Red 92000km
1989 Isuzu Piazza JR120 Lotus Turbo White 183000km
1987 Isuzu Piazza JR120 Pre-Lotus Turbo Red 131000km
1984 Isuzu Piazza JR130 N/A Two-tone 145000km
1984 Isuzu Piazza JR130 N/A Black 92000km
1989 Isuzu Gemini JT190 Red 173000km
IZU069
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Post by IZU069 »

LOL - the old suck it & see approach.
Or the subs(titute) till it works....

Not that I would ever do that... I mean, figuring out the problem and THEN reverse engineering the solution....
THEN figuring out the neat way to pick it next time....

Since I was born with all the knowledge I ever needed.... (LOL - so many seem to think so. Hence why I/we are smartarses etc. Don't they know that you lean more from your mistakes ... yeah, geez I know a lot! But I am happy to let those with that attitude learn the same way I often did...)


But thanks for the solution...
NOW that I think of it, it isn't the first faulty AFM. My last involved a mechanic that reckoned the AFM would NOT effect his Piazza engine. I think he eventually sold it (with the Gemini it was fitted in) and that solved his problem.... I don't think he/she recovered the $10,000+ spent on that Gemini, but I assume spending was part of his hobby....
Dritt Huvud.


Actually the Piazza AFM should be simple - it is "digital" (meaning 2 switches) and is fully open, fully closed, or anywhere in between.
Not very hard to imitate - except maybe its "nearly" full closed/open transition point if that's critical.
And the are a common AFM "type" with some having an additional fully variable resistor attached (Nissan?).


And BTW - the "not closed" AFM switch is another good fuel pump controller. That's for those that want redundancy to the charge signal without adding spark/ignition sensing. (Unlike others, I don't think the Piazza uses oil pressure to control the fuel pump - hence it passes competition safety regulations. Camiras use oil pressure - which overrides any other fule pump conntrols - and some Rodeos, Jackaroos etc use oil pressure as part of the ECU's control process....)

Ramble ends.
IZU069 - ISUZU means a lot to me.
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wedgenut
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Post by wedgenut »

Here is something else to start you rambling again. In the past there has been lots of talk about the Piazza flap style AFM and its habit of sticking or the contact strip getting scunged up etc etc etc. This is usually followed up by asomeone saying hot wire is a better method. No one yet has mentiuoned the third option, why not pinch a "map" sensor off a toyota and use that instead. Goodbye to AFM problems, after all they are also either off or on arn't they?

WELL the question has to be asked dunnit?
So many cars, so little cash
IZU069
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Post by IZU069 »

WTF? Is this the thanks I get for "sync'ing" my mum's netbook to her home-base PC 'cos she has dial-up and hasn't updated for a while (was it 199? or 200?, or 2010?) whilst sucking on $2 wine (bottle, not cask!) and NOT abusing you since her last updates? (Ok, that makes it after year 2,000.)

Hi Wedgy!

Alas different sensor means different ECU so it's no good for the st'd Piazza.

Of course "we" had the recalcitrant Bosch type ECU with MECHANICAL dizzy unlike some of you lucky ... er, comrades & comradesses that had the DOHCs with the 5 year OLDER I-TEC with FULL digital ignition....
(Anyone read the fun discussion on Holden's mechanical dizzy versus the Jap electronic I-TEC on BellettNet? Anyone read my objections to transference? LOL!)

And AFAIAC, AFMs & MAPs are all primitive tech - but I was into ionic sensing before new graduates even realised ECUs have been self learning for 15 years or more.
AGM or MAP - I don't care - I'd rather see what the (actual!!!) combustion is doing....

Alas, $2 - no, $3.50 of wine makes me whine aggressively.... [I daren't mention darpick harpeads that prefer lean-blowing engines due to stupid (yet traditional) electric fuel pump controls - but at least they understand why certain EMS with "lots of maps" are so stupid I won't even mention them....]

I've had enough interaction on open/public forums about that and the stupidity of low-Z injectors (and voltage sensing), excessive base maps, optic etc dwell angles, smart CAS, "analog" reluctors, fuel pressure & larger injectors, scurge tanks, slower wideband O2 sensors, and quarter-century old realities etc etc to keep me off public forums - at least locally - on those subjects.
(Did you hear that Australia is "like a dumb blonde..."?)


But yeah - you take whatever sensors match your EMS/ECU. End of story.


But I can see the old dizzy argument that optic & Hall is digital whereas reluctor is analog or AC... Amazing how fuckwits choose the least accurate & reliable technology as a result of their primitive understanding.... or superior con artists and mis-informed. I assume the same for air flow....


[ Caveat: The view/s expressed herein may not be the view/s nor endorsed by this site and its contributors; and certainly not the view/s of the "vocal majority". Suggestions herein should not lead to stress; merely enlightenment. ]


PS - other AFMs could be used with analog to digital converters to suit the Piazza ECU.
But then why not a non-sticking Piazza AFM - maybe optical choppers etc instead of mechanical switches.
Or the combined analog/3-position_2-switch sensors with a preset but adjustable digi-out on the analog sensor?
Farken too hard - go Delco or go ionic. EOS!
IZU069 - ISUZU means a lot to me.
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