89 IROC Hard starting/No starting
 

Cold, fires right up, let run for 5 minutes, shut off, try to start, cranks over like 10 times then fires up, let run for a little bit more, shut off, try to start, just cranks and no start.

5.7L TPI

Just replaced the ignition coil and rotor and ignition module in attempt to fix this, didn't work :icon_doh:


So what could the problem be?? :icon_shrug: I pressed on the fuel pressure valve thing and it sprayed fuel out so i guess it has fuel pressure.


All tips/help is greatly appreciated!

Just went out to start it after it sitting for roughly 15-20 minutes, tryed starting, fired up, let run for like 20 seconds, shut it off, then it wont start again.. wtf!

It's a sensor, somewhere. I'm not knowledgeable enough of what they all do to say which, but getting a new o2 sensor first isn't a bad start.

I hear a lot of things rely on that o2 sensor.

Thanks for the reply Horizon, ill look into that.

Any other ideas anyone ?

A bad oxy sensor isn't going to keep an engine from starting, as it reads the exhaust gases after the engine is running (and warmed up). Have you checked for spark when it goes no start? Sounds like something may be overheating, either ignition, or the fuel pump, or the pressure regulator. Checking for pressure at the fuel rail the way you did doesn't tell you if you have enough pressure to spray the injectors. You need to check it with a gauge.

Well I just checked the for spark with a screw driver, has spark, and checked the fuel rail pressure with a fuel pressure gauge, has fuel pressure(45psi).

So the injectors must be not firing right? I'll get a noid light from school on monday and test out the injectors..

Since the injectors aren't firing, then the PCM must be fubar'd right?

What about VATS.... the car has vats.. and the resistor pellet in the key is MISSING! but it shouldn't start at all without that resistor??


:icon_hyper: :icon_hyper: :icon_hyper: :icon_hyper: :icon_hyper: :icon_hyper:


thoughts?!

I'm glad I said that, now, because I didn't know it reads after being warmed up. I should have known that. :icon_doh:

have you tried flucuating the gas pedal while cranking to see if that has any affect? it could be that the ecm isnt seeing operating temp and is still injecting the fuel to start a cold engine and might be flooding it out. i think 89 was the first year without a cold start injector. i know my car has 3 temp sensors. one for cold start, one for ecm/fan, one for gauge. yours should have at least two. the ecm on may be bad

I hope its the ECM and not security related.. Im gunna test with a noid light when i get home and ill post what i find out.

ECM is only like 100 bucks on summit right?

The car ran before with the pellet missing from the key, correct??

Im not sure :icon_shrug:

I can't find my other set of keys for it, but it did run good before but i might of just been using the key before with the pellet.

Find the other keys and see what it does. If VATS is working correctly then you should not be able to CRANK OVER the engine. If it spins over without a chip in the key then someone MAY have allready bypassed the KEY READER in the column. Maybe before you bought car.

I feel your pain c4. I have my friends 89 IROC. They bought it but could not get it to start.They changed starter but no start. I get it and they say that it will turn over if you jump starter at selonoid. I bypass key reader and get car to turn over but will not run right, they have plug wires on wrong and timing is way off. Fix all that and drive car but it runs ROUGH, figure injectors are dirty since it sat for 2 years and will deal with it later. Work on other projects for a few days, going to pull trans out of another friends car so need to move IROC, HOP in to move and the dang thing wont stay running. Still sitting there cause it won't run, CRANKS over, just wont run and it ran when I started on other projects at home.

Lol yeah you've got lots of work ahead of you too.

As for finding the other set of keys, easier said than done, i've looked everywhere! Im gunna test the resistance of the coolant temp sensor and see if its working right, cause micro said it could be reading too cold and flooding the cylinders..

Another question:

if i get a new ECM, on summit racing, it has ecms for 5.7L auto's, no 5spd, because the car didnt come with 350 5 speed, but my cars 350 5 speed lol. so will a computer for a 350 auto work for my 350 5spd? lol

A-1 CARDONE 100-777165 - A1 Cardone Remanufactured Engine Control Units - Overview - SummitRacing.com

Well just went out and tested with the noid light, and it lights up when im trying to start it.... so when im trying to start it... it has fuel....... has spark...... and the injectors are firing....

So why isn't it starting :icon_shrug:

And today i went to start it cold and it cranked like 5 times then started, other days it just starts at the turn of the key, although it was sitting for 2 days. And it was also a lot harder today to make it completly not start like where it just cranks forever, i had to let it run longer than usual.

So why is my car having this hard hard start and then no start.

Im am so confused!!!!!!!!!!!!!!!!!!

And and and, just went out after like 5 minutes of it sitting, started RIGHT UP... shut it off right away, and it just cranks again no start. hook up a battery charger and set it to 200amps 12volt, then it will start everytime, after about 6 or 7 cranks but it does start everytime. WTF!

how are the battery terminals? my fuel pump power wire was connected directly to the battery power from the factory and had an issue with the fuel pump and replaced the pump but still had issues. found it was loose at the battery. it is really baffling with your issue though. i would avoid a reman ecm though, just personal experience. fuel leaking down into the intake would cause an extended crank when sitting for a while, but not just 5 minutes later. when my fpr went bad, it would only start if i put the throttle to the floor. keep your fuel pressure gauge hooked up when its running and just watch it the entire time.

The terminals are OK, whats a reman ecm? like refurbished?

That ecm won't come with a prom in it, you have to take the one that is in your computer out and stick it in the new one. I don't think its your ecm

reman is basicly just a used unit, "tested" and jacked up in price over a used unit from a salvage yard. i know of two tpi cars near me in the junkyard, but both are 87 models with the cold start injector and a maf sensor. if i remember correctly, 89 should have a map sensor. may want to check that out as well. i think its mounted under the upper plenum in the rear. pull it out and see if its full of carbon