94 PA starts and dies

[bmw490]

starts runs about 5 secs and dies, won't restart until key is turned off, then back on. Not losing spark but losing fuel injector pulse after motor starts.

[maxwedge]

Welcome to AF, are you sure no pulse, this not a loss of fuel pressure at the rail?

[bmw490]

Thanks, and yes losing pulse, can see test light flashing when motor is running, then quits and motor then dies. Fuel pressure is good 45-50 PSI.

[maxwedge]

It would seem that as this happens you probably loose spark, BTW good check procedure. Try and get a scanner on it and see if you have cranking rpms when it won't stay running, also look for poor connections from crank sensor to the ign module, suspect either one here, get a test lite on the pink wire at the icm see if it looses power as it dies.

[bmw490]

Using homemade adapter and EFILive software for scanner due to being OBD1 w/OBD2 connector, RPM reads 800-1000 then drops to zero and motor dies, doesn't read when cranking after motor dies, but does have spark. Have already replaced crank sensor.

[bmw490]

Have also tried new ICM, made no difference.

[maxwedge]

Look at all the harness from the icm to the crank sensor for one, there is no signal reaching the pcm from the sensor thru the icm.

[bmw490]

metered wires from crank sensor to icm, all four check out, I don't understand why I read RPM when it first starts but not after that.

[maxwedge]

Loosing the cps signal, only way, or the pcm is bad.

[steven david]

having same problem,coding pass key error,vats system seeme to be the culprit,still trying after market module that bypasses vats system(just the fuel enable part)

[bmw490]

I was able to borrow a pcm from another 94 pa from the car lot my son works for. started right up, ran a little rough but loaner was a ultra and I didn't swap proms. Thanks for the help.