Pontiac Grand Prix Forums : Grandprix

it's hard troubleshooting this without having been able to test the pressure on the car, but here goes-- My ('99) GS has been hard to start when cold (really anything longer than sitting half an hour) but seemed to run fine after that. I figure it was the check valve in the FP getting weak, not holding the pressure. Today, i get in the car to run to the airport and pick up my wife. she has been gone all week, and i only moved the car a time or two in that time period. i get about 10 min away from the house, merging onto the expressway. CAR DIES. so i pull onto the shoulder, try to restart the car. it will crank over, runs for just a second and kaput, dies. tried it a couple times and nada, same thing. so i dial up the roadside assistance people for a towtruck. while im on the phone, i get the car to start again, so i hung up, and was going to try and get the car off the expressway, onto local streets. I made it about a mile, and the car quit again, same problem starting. it will run for a split second, then die. so went through calling agian, waited forever, they didnt show after an hour, but a state trooper did happen by and get me a tow. took 15 minutes. so the car is sitting at a local repair shop, i'll have to go see them tomorrow. but im still trying to determine what the real problem is... though i guess there isnt much knowing until they can test the FP pressure.

well, now im more confused. i drove back over to the car, as i had forgotten about trying the fuel resistor bypass trick. i wasnt sure if that would be the problem, but thought i should go check. so when i get there, i tried to start the car. it started! didnt run well at idle, but it started. tried it twice, both times it sputtered a bit at idle, and then the RPM's bounced back between 500 and 1200 or so, then it would end up dropping below 500 and die. if i held the gas, and pushed the RPM's it seemed to smooth out run OK. no SES lights. so i didnt figure that the fuel pump resistor was the culprit, but i tried the bypass anyway, bending out pin 85 on the relay. it would NOT start in this condition. no pump prime or running. i didnt try to drive it, so dont know how it would have done in anything but park. The tach seemed to mirror what the motor was doing, not bouncing around on it's own, so wasnt thinking it is the CPS. any other ideas?

What about the camshaft position sensor. Were you talking about the crankshaft position sensor? Just throwing it out there. I would have to agree that it was more fuel related imo. Shoot if I still had my old fpr i would send it ta ya to try. I dont know how much they are new...probably about 15 or 20 bucks...I know this sounds stupid but did you check all the vacume lines. From seeing you around i know you have the smats to figure it out...so good luck. Hopefully it wont be too long and drawn out.

i didnt look around for vac lines, but when it was running i didnt hear a leak... though you cant always hear em.

i think i need to bypass the fuel pump resistor AT the resistor, as for some reason the relay trick in the underhood fuse box doesnt work on regal's, as i have read in a few places just now. ...that and i think i need to try and unplug the MAF and see how it runs. no SES light, but the MAF may not throw a code...

Hey Toasty!!!!

well...after much thought. MY OPINION... I am leaning towards the CKP (crank). Without testing the fuel pressure you cant rule that out. I would see if that shop is able to test for fuel. that is it. if that tests fine and doesnt bleed off....the Crank sensor MIGHT be bad.

Scotty had this problem where it would die, run fine, then die, then sputter. this sounds just like it.

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2001 GTP street car- GT45 turbo,Stage 4 Intense turbo cam,FMIC,150 wet, double roller timing chain, Diamond forged coated pistons 8:0:1, Diamond piston rings, cryoed L32 connecting rods, Cryoed crank, Clevite77 main bearings, Clevite77 cam bearings, Clevite77 L32 rod bearings, ARP Everything, Intense/meizere true billet Flexplate, Custom UIM, Intense oil pressure kit, Cometic 4 layer head gaskets, OE-R lifters, Cryoed L67 block, ATI turbo dampner, SDD FATMAN FUEL RAILS!!!!!!!!!

could possibly be the CPS, but after it initally quit on me, it did start back up and run OK for a bout 5 minutes, but then it wouldnt start at all, until HOURS later when it would start and only sputter. .... and smell like it was running rich.. so perhaps the MAF sensor?

eh... not the MAF sensor. it actually ran a bit worse without it plugged in.

i thought there was a fuel pump resistor on all gtp's and regal GS's ? didnt see the one on my GS.

Weeell... interesting. Seems the shop tested the fuel pressure, and seems within normal operating ranges. Changed out the MAF sensor... seems to be working properly now. +*%^^+*&(* all of this headache for the dumb MAF sensor. i knew the symptoms seemed to act as if it could be the MAF, but didnt have a good way to test it. i certainly hope they're right about the fuel pump. $350 is bad enough without the fuel pump/associated labor