ok, well yesterday i was driving jhome from my uncles house and all of a sudden , it just tries to kill itself, 50mph down the road and ... suprise! no power, only thing turning the crank is the wheels lol.... so i let the car slow down under the engines compression, and pump the gas and eventualy it kicks back on and we are one our marry little way, but i has happend over and over again, today and last night, it wouldnt even idol, it wit crank over fire up and then die.......i did a fuel pressure test, pressure is at 40psi , and under load spikes to 50psi and lkevels off back to 40.... i replaced the fuel filter just incase.... only other thing i can come up with would be ignition... and ideas?

 

Clogged CaT, clogged injectors...is it popping any codes?

 

Man, what good is the if nobody uses it?

There is a TSB out on the 90-92 cars due to faulty ignition wiring.

https://www.thirdgen.org/forums/v6/8...-you-have.html

I had swapped to a 91 730 harness for a while... And then I got tired of going fine for 3 weeks before random hot stalling would occur. The parts were good (they worked completely 100% fine with the old harness... And don't mention a clogged cat because a gutted cat don't clog), the harness was NOT. Which is why I cut it up.

There is, or at least used to be, a guy on here who got a 100% brand new GM harness from the dealer. Can't say if he is still on here or not or if he still has the car/engine/harness, because I don't know.

 

headers cat and full exhaust is new.. injectors are new, not any codes are getting thrown

ive had this car for 5 years, and i have done alot to it, bean over the harness with a fine tooth comb, .. i tried the search bar but nothing really came up , nothing worth anything at least... only thing i can think of now , would be tps or fpr ... otherwise it must be an ignition problem?

 

oxygen censor is new also..

 

maybe tps? and if so, and it needs to be changed, how would i re learn it to the ecm?

 

Again, follow the link...

1. FPR is good if no gas is leaking out of it and the fuel pressure isn't ridiculously low or high (between 37 and 47 PSI).
2. TPS is probably good.

Keep in mind that without the signal from the ignition module to the ECM, there is no fuel injection. Therefore, if the module or the wiring between the module and the ECM is faulty, the engine shuts off like you turned the key off. And you won't get anything but a code 12, which means that the ECM isn't receiving reference pulses from the ignition module. Just because the wiring appears to be good doesn't mean it is. It should be tested cold and hot. And also make sure that there aren't any wires that are just about broken at any of the 4 connectors between the ignition coil power connector (with the pink and white wires) and the 4-wire connector at the module. Just because the tach indicates engine speed does NOT mean the ECM is seeing a reference pulse, as they are on 2 separate circuits (tach driven off of coil windings and ECM from ignition module).

The best way to check would be to either get a hold of a scanner and hook it up while driving or an ALDL to laptop cable and do the same. That way, you will know if the RPM signal to the ECM drops out.

 

ok, i tested the tps and its good, no dead spot, and doesnt skip... i will pull the distributer apart tomorrow and go through it... where can i get the ALDL to hook up to a laptop and where can a get the program...? i was briefly looking into that eirlier but no luck. pump it putting out 45 psi at idle and tap the throttle and it will hit 50 and level off at 42psi ...it must be ignition, because my air fuel mix doesnt lean out when it kills itself and the fuel pressure doesnt drop untill after the engine dyes

 

Maverick, Thanks for posting this thread. I've added it to my list. I've searched the h*ll out of this forum and found great info, but, sometimes don't find what I need.

Just replaced my IAC, which helped the "sagging" but still getting some sag. I'm pulling the new IAC out to check the distance from the pintel (sp) and gasket. If that doesn't resolve, I'll start going through the "Cold start stall/ Hesitation/ Idle roll and upshift sag" bulletin procedures. Again, thanks. Not the first time one of your posts has helped me.

 

i dont believe i have a cold start injector... and im a wct5 car, idk if that matters because its referring to an auto?

 

bump

 

ok, well i did a test on the fpr and it turned out to be bad so i replaced it, and went for a drive, it felt much more responsive and my air fuel ratio gauge wasn't bouncing all over the place any more. but it still felt like it had a dead spot, i just figured it probably has gunk in the cylinders and it will clean it self up.... so the longer i drove the worse it go, until it would barley run, like as if it barely had spark ... im thinking the coil is bad and the heat do to the new headers and heat wrap its heating up the bracket that bolts to the head over the header... and heats the coil up... any thoughts?

 

ok, so get this.... i went through just about every inch of the fuel and ignition system,,,, and found nothing.... i replaced just about everything othere then the hard lines and the temp , map, and tps sensor... i figured out that the timeing just went way retarded...how the hell? i advanced the timing and boom... car runs ..... unfortunatly my timing light whent out lol , so i have to wait till tomorrow to set it correctly.

 

Do you have a scanner to see if you are getting false knock counts.

 

no i need to get one

 

http://aldlcables.com/

 

what program works the best for watching the live feed... i need to have it hooked up while the car is running and driving to i can see where it tries to die... will it show me exactly which signal gets lost or what malfunctions? what if it the ecm?

 

ok..i set the timing.. so back to the original problem... the consistent shut down under load.
i went through the whole fuel system... everything is new besides the relay...
ignition coil is new,,
ignition control mod is new..
fuel pressure reg is new...

 

I didnt read through the entire post but what do the injectors ohm out when the engine is at operating temperature ?

 

Tuner pro

 

im not sure, i know there new, i did them about 5 months ago. also i just got it to stall in my drivway, and i had the timing light on it, if i rev it rappidly over and over. with the knock sensor disconected, it will eventualy advance like crazy, and kill itself, then you can re start and do it again... im thinking the sensor stopped ready knocks or ijust had a bad connection? and it continued to advance because it doesnt sence a knock or ping?

 

just ran it again.. it is now pulling 16bftc at idle.. and 20 kills it... gets farther and farther every time i run it