TPITuned Port Injection discussion and questions. LB9 and L98 tech, porting, tuning, and bolt-on aftermarket products.
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Ok I got one that has me a bit stumped, hopefully someone else has seen this.
I have an 86 Iroc, 305 TPI. Essentially its stone stock, but it does have 178,000 miles, so it does have some age.
When the car starts it runs fine, no problems power and everything is fine. But after 30 - 40 minutes of running once its gotten nice and well warmed over the car starts acting up, it becomes sluggish when you try to accelerate while moving, and once I stop the idle becomes rough and the car will try to die. Then if you try to pull out the car acts like its being starved of fuel and wont move unless you flutter the throttle the you can nurse it into motion.
Keep in mind all the gauges read fine, temp, oil pressure etc, I dont have a fuel pressure gauge so I know if that is low or not.
Maybe the fuel injectors are bad. When the injectors are cold, they might be working fine and as the injectors heat up, they start to act up. Have you ohmed the injectors? I would also check the fuel pressure.
__________________ 1989 Iroc-z, stock 350 TPI, auto trans, oil cooler, leather int., bose stereo, t-tops, Single Magnaflow cat with Magnaflow cat-back exhaust, 4 wheel disc, gold pkg., and custom aftermarket hood. Pics of my 89 Iroc http://www.thirdgen.org/techboard/me...y-89-iroc.html
look into the IAC valve...(idle air control)....theres a tech article on how to remove and replace them on the boards somewhere...the valve itself is a 50 dollar part at your local autozone so its worth a try...
Im no expert so i cant exactly tell you how it works but im sure someone else on the board will read my post and elaborate...
The IAC valve is a stepper motor and they hardly ever go bad. Just clean the pintle and put it back. Unless you pull the pintle it'll probably be fine. If it's all gummed up that will cause issues. However the IACs are Idle Air Controllers and they do not make a car feel sluggish when driving.
THe fuel filter is fine, well should be anyways its new, but Ill do as you guys suggest and check the ohms on the injectors, and does anyone know any good ways to troubleshoot the injectors.
You can do the basic injector test with a volt/ohm meter. Take your readings when the engine is cold and again when the engine is hot. The injectors should ohm out to around 16 ohms. I think anything less than 14 ohms is a bad injector. This test only checks the injector coil. Not forsure how to do a mechanical test.
__________________ 1989 Iroc-z, stock 350 TPI, auto trans, oil cooler, leather int., bose stereo, t-tops, Single Magnaflow cat with Magnaflow cat-back exhaust, 4 wheel disc, gold pkg., and custom aftermarket hood. Pics of my 89 Iroc http://www.thirdgen.org/techboard/me...y-89-iroc.html
I had a bad pickup coil act like that on my truck (TPI) once. Every 30-40 minutes it would start to run like crap and idle poorly and then die. It felt like a fuel issue but it wasn't. The truck would have to sit for 20 minutes and cool down, then it would refire like nothing happened and would run fine for another 30-40 minutes. I drove 200 miles like this to get home when it happened.
Pics of my 89 Iroc 
