S-10 Running problem

[Stangman]

As some of you know, I've bought a '92 2.5 5 speed S-10... It's in pretty good shape over all, just needs some good TLC..

I gave it a complete tune up and it runs dramatically better. BUT, when I start it up when its cold it runs like a champ, hardly even a miss (I am thinking fuel injector needs cleaned or replaced) But after it warms up and I shut it off and then start it back up, it runs like an absolute turd! falls on its face when you give it gas while taking off... And for the life of me I cannot think of what it could be. I did a compression test on it last night and got anywhere from 120-130lbs per cylinder, also did a vacuum leak test, which told me I was pulling 18-20 on the guage... so thats out too

I used to know what caused this back when I worked for Pep Boys... but that's been almost 2 and a half years ago and now it's lost in memory...

I want to say... module? pickup coil? I just can't think of it... :bangwall:

I got to get this thing fixed so I can drive it. That is the ONLY thing keeping me from tearing up the roads right now in it...

... that and the coolant gauge and oil pressure gauge doesnt work...


Any direction you can point me will be great help to me!

Thanks!

[WhiteT]

Maybe o2 or iac?

[Stangman]

IAC would make it surge wouldnt it? and O2 would cause an engine light right? I'm not getting either of those issues...

The O2 also appears relatively new.

I have a sneaking suspicion that it is my TBI injector... but I can't see why it will do that once it gets hot... you'd think it would be the other way around?

[wolverine8490]

I know on the old Blazer I had, the oil pressure sensor axctually wired into the choke of the carb so that if the car sensed no oil pressure, it would kill the truck or at least try to. Granted its fuel injection, and it starts when it is cold, so I doubt that has anything to do with it.

GM's had some issues with the distributor control modules. Its just a module under the distributor cap that if bad, it will cause issues when the car is warm. I had one go out in my firebird. Started right up when it was cold, but died when it warmed up. Maybe yours is just not bad enough for the car to stop running like mine did. A mechanic I used to know said they should be replaced evey 80,000 miles. I dont think it is to expensive, so you may want to start with that.

[Stangman]

I'll give that a shot... It's a bitch getting to that dizzy though!

[mustangjon]

yes gm modules are horrible for high temp breakdown, but typically it was like the previous stated, usually runs fine cold then takes a crap completely when hot and it breaks down, let it sit for 30 min and it will run normal again. Does yours have to sit over night to run right again or just some time? maybe try getting it hot, then putting a fan over it in the driveway or something for 15 min then take it out again.:confused:

[Stangman]

well it doesn't die, just wants to fall on its face.

Sometimes I can let it sit for like a half hour and its fine, sometimes its like an hour...

I am going to replace the module for the heck of it that way I rule out the entire ignition system, then if it still does it, I will replace the fuel pump/assembly... after I check fuel pressure of course.

[mustangjon]

its possible early signs of it, of course when i sold parts most diy people arent really enthusiasts so they dont know when their car runs good or like shit, just if it runs at all. And yes they well were dirt cheap since they went out so often. Wouldnt be bad preventive measure either way, i doubt its fuel pump if it wont even idle well, usually its only pegged high rpm fall on its face with it, but once again every car has a diff personality.

[DeckerEnt]

I am looking at it another way. When the motor warms up, things get hot and loose. Sounds to me you have a loose wire that could be shorting a little or a ground somewhere that gets less or no contact when it gets warm. Just my .02 but worth checking. Good luck with it Jesse.
Keith

[Stangman]

If it's not pouring raining when I get home... my plan is to check about everything I can under the hood.

[8banger]

I would opt to check that fuel pressure(just to rule it out)...need a solid 12 psi to run properly(check it after the trucks hot(also rev it up and watch the pressure),should rise abit not fall off...Could be the pump heating up losing pressure or volume....I've got the adaptor for the fuel filter(truck maynot have a shrader(I dont believe it does if memory serves me :D ) and fuel pressure tester if ya wanna borrow it. :bigthumb

Also on those,,little pressure,,will most the time idle o.k..
And hows that convertor?Rattle?

[rpppaprp]

Sounds like you should have bought a capri.

[Stangman]

I would opt to check that fuel pressure(just to rule it out)...need a solid 12 psi to run properly(check it after the trucks hot(also rev it up and watch the pressure),should rise abit not fall off...Could be the pump heating up losing pressure or volume....I've got the adaptor for the fuel filter(truck maynot have a shrader(I dont believe it does if memory serves me :D ) and fuel pressure tester if ya wanna borrow it. :bigthumb

Also on those,,little pressure,,will most the time idle o.k..
And hows that convertor?Rattle?

I didn't notice a schrader valve... or even a fuel line for that matter :confused: It was dark, I will check tomorrow. I have a fuel pressure tester though. And I havent checked the converter... It's coming off when I get a muffler put on though.


Sounds like you should have bought a capri.

I tried that angle on my dad... he didnt go for it... otherwise I would have man...