BN Posted December 31, 2013 Report Share Posted December 31, 2013 On my 96 Grand Prix 3.1 (61,000 miles). Out of the blue every once and a while I'll go to start it and it will turn over but not fire up and if it does fire it won't keep running. I've learned that if it does this to turn ignition off and just wait a minute or so and then it starts up. Normally the car runs great. It has probably done this 6 times with weeks in between. I'm thinking the fuel pump is going bad but the mileage seems low for this? Any ideas appreciated. Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted December 31, 2013 Report Share Posted December 31, 2013 possibly VATS/PK2 related. i used to have the same issue starting in ~2005. eventually, it got to the point of then randomly not even engaging the starter when the key was turned. only ever happened when cold. eventually, when i removed and bypassed the need for the PK2 module, it quit happening, so i would like to draw the conclusion that it was the cause. when it fires but stall soon afterwards, how quickly does that happen? the PCM should cut all fuel if it doesn't see the PK2's signal after 2 seconds of ignition-on time. Quote Link to comment Share on other sites More sharing options...
Imp558 Posted December 31, 2013 Report Share Posted December 31, 2013 It does smell like VATS but I don't believe the start enable relay should engage if the passkey module isn't working or seeing the key, could be wrong but that's what the yellow/black wire to the passkey box does. Is the "THEFT" light on when it runs for a few seconds? Is your "Check Engine" light on? A failing MAF can make some VATS like symptoms too. Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted December 31, 2013 Report Share Posted December 31, 2013 the PK module could be seeing the key and allowing the starter relay to operate, but the PWM signal(for some reason) isn't making it to the PCM. this was my exact issue for quite some time. i could get the engine to run for a second or two if i ran the key immediately from off to crank without spending any time in between, then it would stall predictably. Quote Link to comment Share on other sites More sharing options...
BN Posted December 31, 2013 Author Report Share Posted December 31, 2013 possibly VATS/PK2 related. i used to have the same issue starting in ~2005. eventually, it got to the point of then randomly not even engaging the starter when the key was turned. only ever happened when cold. eventually, when i removed and bypassed the need for the PK2 module, it quit happening, so i would like to draw the conclusion that it was the cause. when it fires but stall soon afterwards, how quickly does that happen? the PCM should cut all fuel if it doesn't see the PK2's signal after 2 seconds of ignition-on time. It only runs for a second. Originally before I learned to just shut it off and chill for a minute you could get it going by pumping the accelerator (like starting an old carburated car). Quote Link to comment Share on other sites More sharing options...
BN Posted December 31, 2013 Author Report Share Posted December 31, 2013 It does smell like VATS but I don't believe the start enable relay should engage if the passkey module isn't working or seeing the key, could be wrong but that's what the yellow/black wire to the passkey box does. Is the "THEFT" light on when it runs for a few seconds? Is your "Check Engine" light on? A failing MAF can make some VATS like symptoms too. There are no check engine lights on at all. As for the THEFT light I'm not sure, I'll watch for that next time this happens. Quote Link to comment Share on other sites More sharing options...
BN Posted December 31, 2013 Author Report Share Posted December 31, 2013 Is there a way to confirm this is the problem? If the problem is there a way to bypass system or repair it? Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted December 31, 2013 Report Share Posted December 31, 2013 bypassing the starter disable is simple, just rewire the relay to always allow the starter when in the crank position or remove it entirely and connect its two load wires together. dealing with the PWM signal is a little more tricky. either need to acquire/build 50Hz signal generator or have the PCM calibration changed to not require the signal. Quote Link to comment Share on other sites More sharing options...
Imp558 Posted December 31, 2013 Report Share Posted December 31, 2013 You just cut the yellow/black wire at the passkey module and tap it into the black/white ground wire to disable the start relay. If you could make it run by pumping the gas and playing with it this is a moot topic, it's not VATS. IAC? MAF? Quote Link to comment Share on other sites More sharing options...
BN Posted December 31, 2013 Author Report Share Posted December 31, 2013 You just cut the yellow/black wire at the passkey module and tap it into the black/white ground wire to disable the start relay. If you could make it run by pumping the gas and playing with it this is a moot topic, it's not VATS. IAC? MAF? I guess I can't say for sure that pumping gas worked as this was a while ago. After reading all kinds of different VATS stuff from Google I think this is probably the problem. I'm going to start with trying the spare key and see if the problem persists. Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted December 31, 2013 Report Share Posted December 31, 2013 if pumping the throttle always worked, then yes, VATS isn't the problem. TPS/IAC/MAF/injectors/CTS would be good places to start checking. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.