Revelation Z28

iTrader: (10)

well from all my "stalling" topics, i moved onto one of the bigger problems the fuel pump. i replaced it with a GMS 255 walbro and it still stalls on idle.

today when test driving, i started the car multiple times, and it ran great. drove around the block 2 times and came back to the driveway and bam it cut out. cranked back up and SES/fans came on it wouldnt do it again until i restarted it and it took a little effort to restart (need to use the gas pedal). it only happens once the engine gets hot, cold starts are great and itll idle as long as i want it until it gets to around 3/4 temp.

the car is getting spark, its getting fuel, its getting air, but i dont know what the hell is going on. ive replaced almost everything that could cause an idle stall and hard starting when hot.

i cant get access to an OBD1 scanner anymore. the only scanner that was obd1 i used was an innova obd1&2 that wouldnt connect to the PCM unless i declared the car a truck.

when painting my valve covers, i noticed my pushrods were very easy to spin, and the rocker arms were all aligned none were lower or higher than the other which is wierd as hell.

my o2 sensors have alot of carbon on them, thats my next move. or the speed sensor. i dont know of the PCM could be bad, or one of the ABS sensor wires for the front passenger side wheel was a little burned from the LT header.

Formula WS6

iTrader: (17)

ever change a fuel pressure regulator? When it gets hot, shut it down and pull the vac line off of the regulator and see if there is a strong fuel odor if not fuel coming from the regulator. From what you're explaining, it seems to be your likly cause.

Revelation Z28

iTrader: (10)

i just replaced it due to the old one letting gas into the vacuum line and causing a backfire. my vac line still faintly smells like gas from it.

spyonu2007

I went through 3 (three!) Aeromotive fpr's on my Trans am, before getting one with the new diapram (there was a recall on those). Good luck, my car did the same exact thing with every fpr failure.

Revelation Z28

iTrader: (10)

i had a napa one in there before and that lasted me 2 years. then its diaphram let go. so you guys think the new FPR is causing it? i can recall this problem starting when the old one was still in there leaking.

infinitebird

iTrader: (11)

stop guessing and get a scanner. You should always have one with these cars. If you have a laptop just order a cable and dl the free software.

Revelation Z28

iTrader: (10)

well thats why i put in the OP that the scanner i was using was never able to connect to the PCM even though the DLC had power.

infinitebird

iTrader: (11)

I would guess that scanner is crap then.

Revelation Z28

iTrader: (10)

lol for $200 its 50/50. it worked in OBD2 mode though on the truck.

infinitebird

iTrader: (11)

well I'm just saying, however you decide to fix the problem, you should get something that works to scan your car. otherwise you are just guessing and throwing parts at it.

Revelation Z28

iTrader: (10)

yea i want an autoxray but no one carries them.

infinitebird

iTrader: (11)

well do you have a laptop? you can get a cable for like $50 that will work. plus then you can actually datalog it and not just read codes.

LiT1_up

iTrader: (16)

I had a simular problem on my 94, replaced the opti and all was good. If you haven't, also look at the ICM and coil.

Revelation Z28

iTrader: (10)

opti is 8000 miles old, coil is new and ICM is new.


nope no laptop sadly.

oh i forgot to put in that when its hard to start when hot that while cranking itll smell like something is burning. i think oil. and my charcoal canister is bad maybe causing a vacuum leak?

BTC

Someone on camaroz28.com just experienced this and their fairly new Accel opti had apparently failed. They figured it out using a scanner. It was throwing one of the opti codes once the car warmed up.

Revelation Z28

iTrader: (10)

i checked for spark when it was hard to start and when the SES came on as i was cranking i didnt see any wierd pulse difference in the spark timing.

Revelation Z28

iTrader: (10)

here is the opti harness. terminal A's wire has bare wire showing from the opti connector 1-2mm up. some of the strands are broken. terminal A is also for Low Res pulse.

top wire:

gatorhead

iTrader: (4)

I couldn't agree more for live scanning it or otherwise you are throwing money at it in hopes that you have fixed the problem.

There is a small chance that it could actaully be the temp sensor. It will make the car run like it has a bad O2, but the only way to actually check that is with a scanner.

camar0corey

iTrader: (22)

Drag your desktop to your driveway. Seriously though, you have to know someone with a laptop, just borrow it and run freescan at least and see if you get anything.

Slowmaro95Z28

Had the same stalling problem. It was from extending the o2 wires like Pacesetter said to do when installing the lt's. I got new o2's from a dealership and got o2 extentions. My car runs perfect and this was over a year ago. If you extended those wires check the connections for water or just loose wires.