bad idle, no reving etc...

[Teds89IROC]

Most of you saw my thread about my tow home at the beginning of the week, this is related to that. So far I've replaced the IAC (old one wouldnt move), TPS (while I had the TB off, why not) and I put the stock GM ignition control module back on, an aftermarket one was on there before. I'm having the same problems still, car will start up fine, but won't idle unless I give it gas and anything above 1500 rpm is fine. The problem is in gear I can't even get the rpm's that high. The fuel pump works. It's definitely electrical related, any ideas?

[maroman88]

quasar34 had a similar problem, one of his fuel injectors shorted out, he checked it with a noid light and found one that didnt light up as bright and replaced it and it fixed the problem... 89 TA wit 305TPI

[12secondv6]

I had this on the v6.... and it was vaccum related. Best of luck

[Teds89IROC]

very interesting, I'll have to check out the injectors. The reason I say it's electrical is because I've had something similar happen. I cleaned/added grounds because the computer would cut out, and I was fine until sunday night when after a spirited drive I came across all these problems. It's this stuff that gets me thinking about a carb swap lol

[BonzoHansen]

Fuel Pressure?

[Pampered-Z]

Timing issue? How many miles on it?

[JSPERFORMANCE]

check the fuses for the injectors, if one os bad the you could be running on 4 injectors.

[its Jeanne-Marie]

I'll have to check all this stuff tomorrow when I get back home. I'll keep you guys posted. Thanks again

-Ted

[Teds89IROC]

Well, my fuses are fine and I can't keep the car running long enough and steady enough to unplug an injector at a time and see if there is any difference. I also see/smell gas in the oil, I'm wondering if it's the FPR. Anyway, I have tuning stuff and right now I'm borrowing a lap top, so I'm gonna try and datalog and hopefully I can post up the screen here or on moates.net and see if anyone can make sense of it..whether it be spark related or the injectors or what.

[Tru2Chevy]

If you have gas in the oil it could very well be an injector problem. I would be careful about running the motor - sounds like you're washing down at least one of the cylinders with fuel, and gas doesn't lubricate like oil does.....

- Justin

[Fast92RS]

you most likely have a bad leaking injector.

[Teds89IROC]

Do you think that would show up on a datalog with injector pulses or whatever?

[maroman88]

if its a bad injector i would imagine, cuz it wouldnt be pulsing, or atleast have a different pulse, im not familiar with datalogging tho lol

[BonzoHansen]

I might think if you pulled the spark plugs the bad cyl would be evident.

[Teds89IROC]

I think I'm set for tuning/datalogging so I'm gonna give it a try tomorrow night when I get a chance and if that doesnt show anything then I'll pull the plugs.

[IROCdan330]

the computer is going to show you a calculated pulse width based on a bajillion other things, you cannot see through the datastream individual injectors due to TPI cars being batch fire cars. The vehicle needs to be able to reach closed loop in order to make intelligent fuelling corrections, otherwise its operating blindly (no feedback from other sensors and such).

If you smell gas in your oil then it could be a leaking injector, your fuel pump cannot provide enough pressure to have a "spray" so the injectors are dripping when they open, or you are getting little to no spark so the fuel just goes in and washes out the cylinder.

[JSPERFORMANCE]

go dan, go dan, go dan, go dan, woot woot!!

Thats some intelligent stuff right there..

I even had a hard time understanding you!!

[chrisfrom nj]

i had the same problem with the 88 gta i bought it to the dealer they changed the computer this and that cost a lot of money when all it was was a clogged gas filter i found the problem myself now the car runs great

check the dist also

[Fast92RS]

I would say before you start dataloging. pull the plugs and see which one is fouled up and which smells like raw gas and go from there. Then replace the plugs. I would try disconneting the injector from the cyclinder that had the fouled plug and see what happens. If it more than one fouled plug than you could have a coulpe injectors bad or some bad plug wires. Measure the resitance on all the plug wires and make sure none are rubbing against anything that may have shorted them.

[The Fixer]

Originally Posted by Fast92RS

Measure the resitance on all the plug wires and make sure none are rubbing against anything that may have shorted them.

Checking the plug wires is a good idea too. If you have them even remotely close to the headers, there's a good chance one is cooked, causing the bad spark issues. I've done that more times than I care to remember over the last few years.

[Fast92RS]

Also there's a good chance that if enough fuel got by the o2 sensor it probably has gone bad and should be replaced. If you still have a cat and too much fuel got in to it there a good chance it can start to melt and clog up cause running issues.

[Teds89IROC]

Thanks for the replies guys. I had a death in the family, so I've been busy with that but later this afternoon I plan on checking my fuel pressure and going from there. The fuel filter on the car is at least 6 years old (I have to keep soaking it in PB blaster) I then plan on checking my spark if the fuel pressure is good and I can move on. I'll pick up a tester.

[Teds89IROC]

Ok, so the guage I have doesn't fit the valve on the fuel rail and I can't get an attachment for it. I think I'm going to just go ahead and order one made to stay attached to the rail from jegs or summit. On a positive note, I was able to pick up a spark tester and I have spark at every plug. None of my wires are touching or arching or anything and they all look fine, so I can't wait to throw a guage on the rail and see what it says. Also, I forgot to mention before, but Dan is the friggin man! We've been PMing back and forth regarding these issues and he knows his stuff!

[Teds89IROC]

so after showing a pep boys rep. how to do his job I picked up a fuel pressure guage that fits my car. At 1000 rpm (cold idle) i'm at 15 psi. I've been soaking the fuel filter connections with pb blaster for a couple days so tomorrow I'm gonna get that off and see what happens. Dan might be right saying it's the fuel pump lol we'll have to see.

[JSPERFORMANCE]

sounds like the fuel pump to me. Turn the key on and let it prime, then look where it peaks and where it drops off. If the needle will only go to 15 psi replace the filter and re test, then if that makes no difference the pump is probably at fault.