98 gtp starts does not run

[zmeade1990]

i have a 1998 grand prix gtp. the car will turn over, run for a few seconds, and die. i bought a new fuel pump relay, it ran fine for a day, and started acting up again. then i bought a new maf sensor, it ran fine for a day, then started acting up again. its throwing codes p0102, p0122, and p0422. i cleared the codes and it still does not run. if i give it gas it will rev up for a few seconds, and die. i talked to a guy that seems like he knows a thing or 2 at the local autozone and he said it sounds like a bad map sensor, somewhat of a common problem in pontiacs (so he says). i have tried running with maf unplugged, same problem. ive wasted time and money trying to fix it myself. any insight would be greatly appreciated :)

[FordMan77]

Sounds like it's dropping fuel pressure once the initial prime from turning the key is used up. Have you checked the fuel pressure regulator? With the engine off, pull the small vacuum line off of it and see if fuel runs out of either the line or the regulator. If so, then replace the regulator.

Other thought is try bending tab 85 (IIRC) out on the fuel pump relay and put it back into place. Try and see if it runs like that. This puts the fuel pump into high-speed mode permanently.

Check this link out for info on the relay test...

http://www.grandprixforums.net/car-w...nds-75132.html

[zmeade1990]

after doing some research i found vats security system, pcm, and bcm might cause similar symptoms. clueless on how to troubleshoot or fix this problem

[zmeade1990]

i bent out the resistor tab on the relay before, it worked for a short while, and then the same problem

[zmeade1990]

just checked the fuel pressure regulator, no fuel came out but the vac line connector is cracked. but this is a recent problem and i doubt that would be causing it. any ideas??

[Scottydoggs]

fix the vac line, its 20 cents for 2 inches of vac tubing. if its the vac line on the fuel rail that could be your problem.

[zmeade1990]

alright. a few connections look questionable so ill pick up some vac line and a few connectors and keep you posted. being without a vehicle i might pick up that map sensor just in case its not the vac lines. thank you so much for your help guys, im lost in the sauce without your help

[Scottydoggs]

i spend a bout 5 bucks at advance auto got a pack of 2 T's and 4 feet of vac tubing. replaced the whole loop around the motor.

like this.

[zmeade1990]

i found the larger vac line on the other side of the motor by the intake with the "u" shaped connector and the connector was completely severed. possible cause of the problem??

[Scottydoggs]

today is your lucky day, i also broke that line. it was part of the 5 bucks in tubing. i got 4 inches of fat line to fit the fat port on the TB, then the smaller line fit inside the fat one, then pushed it on the stock line, it goes to the evap sensor on the back of the super charger.

a little spit makes them slide on nice too.

[zmeade1990]

now that i think about it, the car has bad brakes, i was told when i bought it that they just need to be bled but maybe its a vaccuum issue. between that and the motor dieing its starting to look like a definite vac problem

[Scottydoggs]

once you get all the lines fixed, lets hope it idles enough to run some, spray some carb cleaner around the lines and the fat hose to the vac booster for the brakes, as well as the booster. if theres a leak, the idle will jump up when the spray hits a leak.

hows the brake pedal feel? hard as a rock, like when the car is off if you pump the brakes a few times? or mushy and hitting the floor?

bad wheel hubs will also make the brakes feel like crap, as the rotor is moving side to side as the brakes are trying to clamp it. you can jack up each wheel, lugs still tight, and push and pull the tire at the top, watch the rotor at the caliper, if you see it moving, and feel it moving, the hub is on its way out.

[zmeade1990]

they go just about all the way to the floor. theres no turbulence or anything in the pedal, it does feel as if the brakes need to be bled, maybe the brake booster is giving it that same feel. im about to get a ride to autozone in exchange for installing some brake pads lol, so after thats done ill hook up the new vac lines and connectors and give it a whirl.

[Scottydoggs]

id try to bleed them before buying pads. see if you can get the pedal back to firm when the cars running. could be a bad master cylinder if the pedal is still mush after bleeding them. dont let the master run dry while bleeding, keep it at 1/2 full to full, no less then 1/2 to be safe. it goes fast too. some cars have 2 bleeders on the abs pump, bleed them as well if you have them.

first and fore most would be getting it running before i dropped a dime on anything else.

also check the fluid level, if its low you can get a soft pedal, as pads wear, the fluid gets lower.

[zmeade1990]

Lines repaired, no dice. Maybe a computer or module needs to be flashed? I disconnected the battery and ill go back at it in a little bit

[Scottydoggs]

here are your codes.

P0422 Main Catalyst Efficiency Below Threshold (Bank 1) clogged cat maybe. before it started this not staying running bit, was it gut less. like floor it and it goes slower?

P0122 Throttle Position Sensor/Switch A Circuit Low Input - Check Engine Light Code throttle position sensor. check the wires, take it off, clean it, if it pops the code again, and new one may be in order. check the plug wires.

https://www.google.com/search?q=p010...hrome&ie=UTF-8 maf. you said you changed it, and tried unplugging it. check all the fuses in both fuse boxes for a blown fuse, its for the maf. also check the wires to the maf.

cracked insulation on the wires can cause the same code as a bad sensor. being they bake in the heat from over the cross over, it happens a lot.

[zmeade1990]

Just hooked the battery back up and still won't run. Any idea on how to flash the pcm? Also thinking about the security system. Or maybe the map sensor

[Scottydoggs]

you pcm is fine, either your cat is clogged up real good, or that fuse is blown. you look for it yet?

you could also take the o2 sensor out, the one in the rear exhaust manifold,(back of the engine) see if it will run then. this makes a nice exhaust leak, but if it now runs, the cat is clogged.

[zmeade1990]

ill do that tomorrow. i also bought the map sensor for ****s and giggles. cant find it though lol, every diagram i look at has it right where the supercharger is. but if that doesnt fix it ill return it. also maybe the security system? might try resetting that too.

[Scottydoggs]

its the one the vac line from the t under the snout leads to. but that should not keep it from running. if it was bad you would have a code for it.

like i said, you have a clogged cat, or the blown fuse or bad wires to the maf. all of these can and will keep the car from running.