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Isuzu 3.2 deteriorated to non starting

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Isuzu 3.2 deteriorated to non starting

Postby MartinH » Sun Oct 18, 2020 11:13 am

Hi Ive a 3.2 V6 Bighorn petrol from 1992 which is normally great to drive but its recently deteriorated to the point of no longer starting. It would run well for a while until warm and then slow down and throw up a CEL. However when id go to check the code by turning the engine off and ignition back on it would always of cleared and give the all good 1-2 flash. The engine would also be fine again so long as the car was turned off for a few seconds. I thought i could get away with this for a while but wishful thinking. It got worse with the idle fluctuating markedly. I checked the two sensors at the start of the inlet manifold, ie throttle position sensor and the Idle air control valve and both seemed to work normally. When i removed the TPS the CEL flashed that code and the IAC seemed to operate normally with voltage applied to it.
So i thought it may be dirty fuel as its sat for a while due to covid. I put in a fuel conditioner and not long after that it began not starting. I thought maybe i had loosened some gunk in the fuel system but on further investigation with an induction light i have no spark on any cylinders.
I checked the connector plug on the far right of the engine when looking at it to the coils and that had 12V and Neg when the ignition was put on. Ive noticed that the car is not showing any rpm when its cranking so im suspecting its the crankshaft position sensor, although im not on solid ground at all in my mechanical ability.
Ive being trying to find the Crankshaft position sensor but having no success. Can someone please let me know where to find it. I live in NZ where the drivers side is opposite from American models. Im trying to add a picture but cant seem to get it under 500kb
Thanks for giving it some thought
MartinH
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Re: Isuzu 3.2 deteriorated to non starting

Postby geeves » Sun Oct 18, 2020 1:54 pm

A free program called Irfanview is great for resizing pictures although Im not sure what you can take a picture of
Sanding your knuckles before starting work can help. That way you cant skin them
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Re: Isuzu 3.2 deteriorated to non starting

Postby MartinH » Sun Oct 18, 2020 4:12 pm

geeves wrote:A free program called Irfanview is great for resizing pictures although Im not sure what you can take a picture of

Haha yes it was just a picture of the engine bay, ive always liked threads with a picture of some sort so thought id try and add one. Il try it again thanks
MartinH
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Re: Isuzu 3.2 deteriorated to non starting

Postby MartinH » Sun Oct 18, 2020 6:42 pm

Engine picture
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Re: Isuzu 3.2 deteriorated to non starting

Postby geeves » Mon Oct 19, 2020 6:22 am

I see a lot of vac hoses on that engine but really my money is on the ecu which isnt a good place to start. Can you get a code while cranking? May have to use a scanner
Sanding your knuckles before starting work can help. That way you cant skin them
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Re: Isuzu 3.2 deteriorated to non starting

Postby MartinH » Mon Oct 19, 2020 8:24 pm

geeves wrote:I see a lot of vac hoses on that engine but really my money is on the ecu which isnt a good place to start. Can you get a code while cranking? May have to use a scanner

Yes vac hoses sprout out everywhere and none are new too. Ive checked them all over and none are leaking.
Unfortunately i dont get any CEL code apart from the all clear 1-2 flash.
Ive found the Crankshaft position sensor, it definitely wasnt designed as priority for maintenance on it. Its on the drivers side (left side looking at the car from the front in NZ). Its under the exhaust manifold and by the engine mount and in front of the oil dipstick tube. To undo it was no joy. The tire came off and then i accessed it through the wheel well. i used a 10mm socket with a UJ on it as you cant get a straight run at it due to metal brake lines. If you have a thin walled 10mm spanner you might be able to fit it on and access it from under to the rear. To remove it i pried it off with a screwdriver and then ran the gauntlet by shoving my hand in the tiny gap to pull it out.
I had traced the wires from it earlier and had 12V and neg on them and i couldnt get anything on the signal wire, i think i should of being able to get a Vac signal but i might be wrong there. Im going to try and get one second hand or on ebay as they arent too bad $20 brand new on that compared to a shop.
Im not very certain here Geeves so will think about the ECU too thanks
MartinH
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Re: Isuzu 3.2 deteriorated to non starting

Postby MartinH » Tue Oct 20, 2020 6:08 pm

Ive Ohmn tested the two pins on the sensor and its open, that is apparently a fail. So im ordering one new from the US $32 including freight, due in two weeks, will update with results.
MartinH
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Re: Isuzu 3.2 deteriorated to non starting

Postby MartinH » Thu Oct 29, 2020 4:19 pm

geeves wrote:I see a lot of vac hoses on that engine but really my money is on the ecu which isnt a good place to start. Can you get a code while cranking? May have to use a scanner

Yes my money is on you being right Geeves, im just a shadetree slapper about with these Isuzus. I put the new crankshaft position sensor on and the rpm gauge goes up a bit now, to about 350rpm but im getting no spark at all, even when pulling out a sparkplug or so so she spins faster.
The ECU is that the ignition control module under the coils?
And what are the diodes in the fuseboxes? How do i check them? Ive never come across those before
Thanks
MartinH
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Re: Isuzu 3.2 deteriorated to non starting

Postby MartinH » Thu Oct 29, 2020 4:54 pm

I tried this troubleshooter and it shows the 12 v and good ground to the computer thing under the coils and the CKP sensor test to it also seemed to pass so according to that im up for an ECU
https://easyautodiagnostics.com/isuzu/3 ... le-tests-1
MartinH
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Re: Isuzu 3.2 deteriorated to non starting

Postby MartinH » Thu Nov 19, 2020 9:24 am

Im still awaiting the ECU (ignition computer module) from the US. I got it new for about $50NZ.
Im currently cleaning up the coils etc. Im just wondering are they meant to have clean grounds where the bolts go through that hold them to the base?
On my outboard the coils use these spots as grounds and im wondering if its the same here, if so il get into them with sandpaper, if not il leave this brittle area untouched
MartinH
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Re: Isuzu 3.2 deteriorated to non starting

Postby MartinH » Thu Nov 19, 2020 9:27 am

IMG_20201119_122604.jpg
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MartinH
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Re: Isuzu 3.2 deteriorated to non starting

Postby MartinH » Thu Nov 19, 2020 10:44 am

Ok i think i just answered that question by remembering that there is a ground wire(that ive already tested) going to the ICU.
Ive resistance checked the coils and they are all 5.7-5.8 ive no idea where the decimal point should be ie they could be 0.57 ohmns to 5.7 ohmns to 58 ohmns. But they were all similar and none were infinite so im picking they are all ok. So launch is all waiting on the ICU to arrive.
Ive also ordered a cambelt for $10. Does anyone have a link to how to change one of these on this motor? I think that to add tension you pull on the cambelt with a specific weight/force and then tighten it off
MartinH
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Re: Isuzu 3.2 deteriorated to non starting

Postby MartinH » Thu Nov 19, 2020 11:54 am

So i've also found out i had another confusion. The ECU is not the name for the thing that the coils sit on, thats called the Power Control Module or Ignition Control Module. The ECU apparently sits inside the cabin by the foot kick panel. Its the PCM im replacing and it better be that thats faulty!
Ive also checked another website where someone checked their coils and they had similar values at 5.7ohmns
MartinH
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Re: Isuzu 3.2 deteriorated to non starting

Postby MartinH » Fri Dec 04, 2020 9:46 am

The ICM turned up eventually. So i installed it and once she pumped gas through ( i had changed the horrid used fuel filter) she started. The check engine light was on and there was no RPM. :cry: Since i had recently installed a new crank position sensor i didnt think it was that. I removed the CPS input into the ICM and she wouldnt start so that ruled out the CPS been the problem. I then did a slightly whacky idea of installing the old ICM and she fired up which she hadnt done previously. So this car seems to have a bit of its own mind like Herby. I figure that the ICM i ordered is faulty (made in China) or its not the perfect part match and so is useless. But why it took the installation of the new one to get the car going again i dont know.
It doesnt run too well at the moment, check engine light comes on now and again so im thinking of scrapping her unless anyone has better ideas, i could risk sourcing a ICM locally but i dont know if its that or the ECU
MartinH
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