My Isuzu Piazza 1987

[sake007ro]

So,
I have an Isuzu Piazza,Impulse in the States,NON TURBO equiped with the G200 ENGINE.These cars seem to have some problemes with the idle speed.Mine too.
After i checked and serched the problem,i guess it comes from the Air flow sensor.
I saw on the internet that the TROOPER came with the same G200 engine in the 84`s-85`s.Does anybody know,could i find an Airflow sensor on this car(trooper).I can add that the car has auto transmission,and everytime i adjust the idling speed,after a while it goes back to under the seted value.After i adjust it in normal position,when i shift it into DRIVE it goes near to dying-the rpms drop a lot.That happens everytime-once i adjusted the idle speed much higher than normal,so when i put it into drive it arrived just at 950 rpms-but in neutral had 1500!!!
I will try to take also some pictures and post them on the forum and maybe get the problem fixed.(i am a beginner)
In general the car has no power-i checked the compresion-good.Whenever the engine is cold and i accelerate it,it chokes,drops in rpms and after that goes accelerating again.
Another sympthom of the car and maybe related,is that everytime i signal left or right,the needle from the voltmeter fluctuates with the signal and the rpms wich go up and down,up and down.
I have a MAS from an Isuzu Piazza Turbo,but when connected the engine starts but dies imediatly.
So,these are the sympthomes of my car...i hope someone can help me with some advices.
Thanks a lot!
I don`t know how u watch the pictures on this forum so i`ll put the link.
This is my car:
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[wedgenut]

I don't know about the trooper in the states but the ones equiped with G200 engines here were not fuel injected. They were carb fitted.

It could be the air flow sensor but on auto cars there is an idle up solenoid to prevent stalling when engaging drive, at least ours do. On rhd cars it is on the inner guard (fender to you) just above and opposite the air con compressor. That wouldn't cause the loss of power of course. There are so many things to consider from low fuel pressure, blocked fuel filter etc. It would pay to check all those things before jumping into the AFM assumption.

Get on ebay, there are plenty of Isusu factory g200 impulse manuals on there in the US and they are cheap and worth their weight in gold. The diagnostic steps are well thought out and easy to follow.

One other thing, make damn sure all your vaccum hoses on the plenum are secure with no leaks as they can offer a variety of problems from hard starting, poor idle, no power, running lean, blowing the head gasket and so it goes on.

Also check for leaks on the main air hose to the plenum. Check the AFM flap is free to move easily and your air filter isn't full of shit and dust and old dead birds that have made a nest in the inlet tube behind the grill.

Keep us informed with how you get on, we will help as much as we can.

Oh and welcome to our happy band

[sake007ro]

Thanks wedgenut.
This morning i went to search an MAS at the most authorized shop we have here but they don`t have one,they have to search and call me.
Today i noticed that when i accelerate the car,the MAS sound like an old prehistorical bird!!!!
I pulled it off the filter box and put my ear next to its hole and sounded like shit.
I will try to look at the hoses too.
I thought disassembling all the intake manifold to clean up a little bit and have space to check the hoses.
I will post again after i do those things.

[wedgenut]

if you get in a funk with the hoses let me know, I can help you with where they all are supposed to go and what they attach to, I have three NA g200's so can even take some pics for you if needed

[sake007ro]

Ok,pfu,man it was a long day!
I changed all the hoses i could(little ones i mean),i ripped off the grill that is behind the filter box-i read on isupage that thing really obstructs the air flow-i cleaned the two MAS elements with carb cleaner.
SAME SHITTY RESULT.
The idle flucuates big time when the MAS connected and it doesn`t when the MAS is not connected.The difference when the MAS is not connected is that the car chokes after i accelerate it,but it also does that when the MAS connected and engine is cold.
So my conclusion is that may be the MAS.
Anyway,i can`t seem to find the EGR valve-i have a Isuzu Impulse JR manual that i bought from ebay,and in the pictures i see the egr valve on the intake manifold but mine seems to be a little shorter than the one in the image.
I also changed the idle solenoid(i guess that was it) with one that i fond on my left parts from an Isuzu Piazza Turbo,but the same result-when i step it into DRIVE the idle lowers,drops.
It would really help me if u could send me some pics with the hoses and maybe all the cables u know...cause i am really not sure if i got it good.That when u have the time,off course.
It sure will be a long project but this has been my passin for two years and it will still be for a lot more.
Thanks wedgenut!

[wedgenut]

Hi I'll email you direct regarding pictures.

You are probably going to have trouble finding parts for your car so if you get really stuck for something let me know, I have quite a few non turbo parts kicking about. Do you know what version fuel injection and ecu is fitted?

[sake007ro]

Hi,thanks again for your help wedgenut.
I read the email that u sent me.I will go on with the parts search,after i will figure what parts i really need,and i will write to 117coupe.He was verry kind and will help me!
I will take a look at the ECU and give u it`s number.
The thing is that i really want to transform this car and i will write agin all the details that i want to change and with all your advices,maybe parts from ebay or other locations,i will realise the dream!
At this moment i am at work,so when i have the time i`ll get back with all the details regarding the changes on the car.
Thanks!!!

[Rodeobob]

The fuel injected G200 motor was reasonably common in the USA.

I would try a car wrecker via eBay and see if you can get one.


I would definately advise that you use the factory manual and use the diagnosis procedures it describes. It my not acutally be the AFM It could be related to something else that feeds a signal to or from the air flow meter.


Cheers, Bob.

[sake007ro]

Thanks for your advice!
At the moment i don`t have the time to work on the car,i guess i will during the weekend.I have to because i worked on it last weekend and now i can`t start it.It starts but then dies suddenly,over and over again.
It did that before but just one time;at the second key it would start with no problems but now i can`t make it work...
I will see what else i can do.
Thanks again!

[Madcat]

Isuzu designed relays into the oil pressure and alternator output. if either of these are below the minimum it will kill the engine.

Does the engine continue running if you hold the gas pedal steady and die after you let go of it???





Jim

[sake007ro]

Isuzu designed relays into the oil pressure and alternator output. if either of these are below the minimum it will kill the engine.

Does the engine continue running if you hold the gas pedal steady and die after you let go of it???





Jim

Hi there madcat!
I guess we meet again,this time on different forum!!
Kool world with the technology!
Anyway,to answer your question,when i push the pedal the engine chokes.
EXAMPLE:THE CAR IS STOPED.ENGINE COLD.I START THE ENGINE,IT ACCELARATES BECAUSE IT`S COLD.IF I DON`T DO ANYTHING,THE ENGINE FOLLOWS IT`S OWN PATH,RUNS NORMALLY UNTIL IT GETS WARMER AND THEN THE RPMS DROP UNDER THE SPECIFIED POINT,EVENTHOUGH I ADJUSTED BEFORE.IT ALSO FLUCTUATES IN RPMS.
IF WHEN THE ENGINE IS STILL COLD AND I ACCELERATE IT,IT IMEDIATLY CHOKES,DROP A LOT IN RPMS INSTEAD OF ACCELARATING.
I am starting to think that is a mechanical problem,like the valves,but until i have the money to open up and rebuild the engine i don`t think i`ll solve the problem.
Thanks and i`ll get back on u wiyh those part lists.

[wedgenut]

I'm sure this isn't mechanical, where are you adjusting the idel, not on the quadrant where the cable attaches I hope. First do the standard check on the TPS using the manual to check resistance readings for off, mid range and full throttle. Warm up the engine and make sure ignition timing is correct. Set idle speed on the throttle body screw, not the cable quadrant stop. Some cars also had a fuel cut switch so if fitted check that out as well.

[sake007ro]

I'm sure this isn't mechanical, where are you adjusting the idel, not on the quadrant where the cable attaches I hope. First do the standard check on the TPS using the manual to check resistance readings for off, mid range and full throttle. Warm up the engine and make sure ignition timing is correct. Set idle speed on the throttle body screw, not the cable quadrant stop. Some cars also had a fuel cut switch so if fitted check that out as well.

3

Hello again my friend!
So,at first i have adjusted the idle at the cable where there is the dash pot screw-i didn`t know then the procedure,but after that i bought the manual and i started to adjust the idle from the idle screw,also i tried to do the dash pot stop procedure that needs to be done at the automatic ones.I will try to do a check like u told me,but first,u know i am a beginner,please tell me what means TPS?Wich procedure i have to follow from the manual.I understand that i need a multimeter to read some resistances,but i don`t know from wich dispositive.Anyway,tomorow,cause is weekend i`ll have the time to try all these things and i`ll see what will happend.
Thanks!

[sake007ro]

Could it be the injectors that may be obstructed from spreading gas when cold and after it dilatates runs better???

[Madcat]

TPS stands for the throttle position sensor.





Jim