1990 Cutlass Supreme 3.1 Won't run

Hi everyone,

This car really has it in me and im about to cry uncle. This vehicle starts and will run for a second or two, then dies.

I've replaced
-ignition module
-spark plugs
-Manifold pressure sensor
-ECM
-Idle air control
-Fuel pump
-Fuel filter
-oil pressure sensor for ECM
-Crank sensor

Tested for spark, has nice blue spark in the tester.
Fuel pressure runs around 45 psi.
Checked both the TPS and the coolant temp sensor. They tested well within specs. For the 2 seconds it does run, it runs fine. For what ever reason, this thing is losing injector pulse and dying. Please help

Do you have security system and if so the security light on?

Does sound like a security system problem

No security. The car will run but only for about 2 seconds. Test the EGR, Knock sensor, and O2 sensor. All test fine...like I said, this one is a stumper

Will the vehicle start and run if you spray carb cleaner into the intake? Runs as long as you spray?

Your ignition key doesn't have a black resistor pellet?

Have you checked for codes and to make sure you can communicate with the ECM?

Do you have power to the injectors?

I have checked for codes, no codes present. I am getting data stream from it, so it seems to work fine. There is no resistor pellet on the key. There is no security on the vehicle. I have power at the injectors and they have good pulse-width on the O-Scope, when the car is running. They seem to keep working perfectly up until it dies. It cuts out the same time the spark does. I even checked exhaust back pressure just to make sure it wasnt a plugged Cat, no such luck. The pressure gauge barely got up to .2 pounds.

If you do starter fluid, will it stay running? It may not have a pellet, just a coded key.

Is the pcm new?

When you turn the key to "on", is there anything in the dash cluster that lights up and spells SECURITY or THEFT?

Gonna try the starter fluid trick tomorrow. There is no Theft or security light in the car. Yes, it is a brand new AC/Delco ECM. I have read up on the AllData at the shop and the schematic shows that if this vehicle had security system, it would never start in the first place. I've also been told the same by the techs at GM Powertrain tech support line. However, this vehicle is starting and running for a few seconds before just dying. My only other thing to try is to replace either the PROM, which has been known to go bad on these vehicles, but the symptoms don't quite match. The other thing is replacing the ignition switch, however this doesn't fit the crime either, but its the only things I haven't replaced that can be causing this problem.

Make sure it it plugged in properly, but even a bad prom will not usually cause this issue. The most common issue for this is the icm and/or crank sensor. I have have also had new pcms do this as there are rebuilts. If no spark and injector pulse, then you should scan it and see if the rpms read at the pcm when cranking and no start.

Okay I’m going to try to explain the problem I’m having with mine in the order witch the problems happened, here goes! I have a 91 with same engine and pretty much the same problem. difference on mine is that the pig tail plug/wire going from the ICM to the 3x crank sen is either bad or just lose "I can't tell" it’s a purple and yellow wire that’s supposed to be twisted 9 times for whatever resin I’m not sure but it’s what the wire diagram says it supposed to be like, I ran an voltage meter to the wire and it shows .5 to .6 v all the time while it cranks/runs which is in range according to the Haynes manual I have for this car. When I take the wire and sway it to the right the car will start "gets spark" when I sway it to the left "nothing" no spark. this has been like this for several months now, last Sunday went to drive it after tying the wire to the right and it started fine tried to take it for a test drive to see if it would drive I went to put it into drive and go and got nothing no acceleration or anything put it into park and the car idled fine went to rev it up and it didn’t want to like it was lack of fuel or something I’m not sure what to do I filled the tank up just the day before after finding out what I thought was the problem after trying to drive it the car stalled and then wouldn’t tried several times to start it check for spark and it gets spark but still won’t start I’m thinking the timing chain somehow jumped teeth and now is out of timing any one got any ideas on what this might be?
Thanks Richard!

Tried the starter fluid trick today. It did stay running, so its gotta be in the injectors. I will look into your pig-tail wire problem you had F9thSkynet. I would think with the injectors being the problem, she would run rough, but its not. It will run for about 5 seconds but, like I've said, dies. I've changed both the ICM and Crank sensor. Checking the signal is about the best lead I've had so I'll try that one tomorrow. Thanks all :)