Thread: Surging and won't stay running? help?

Well I'm a new member, I am trying to help out a not so mechanically inclined friend with his 2000 GTP. I guess i'll start off by saying I've never owned one and am not terribly familiar with GM's fuel injection systems as it just not what I've owned or worked on in the past.

But anyhow i'm hoping someone can give me some tips. My friend wrecked his car, the wreck wasn't that bad and he had liability only so he is trying to repair it himself. It would be drivable as-is if the engine would stay running but as of right now it will start and will only stay running with the pedal to the floor and it surges terribly at about 3500rpm like it is hitting a fuel cutout or something. If you let it below about 3000rpm it just slows and dies almost instantly. I have searched for anything that looks out of place and can't seem to find anything. I've checked and solved a couple vacuum leaks were the intake hose was seperated from the intake itself. I've unplugged and tried starting without MAF, TPS, and idle control just to check and see if they had any effect on the issue but they seem not to. I've tried plugging it into my OBD reader but I get nonsence codes? I have an older code reader that actually gives code you look up in a book, but the car gives codes that arent even in the book, almost like hex code 00FF, FFFF, 0c1F... stuff like that instead of the usual numbers. I guess i'm sort of stumped. I'm having my friend tow it to my house so he doesnt get it impounded from his aparment compex and i'd like to help him out.

Thanks,
Paul

Well, taking longer to get it towed over here, guess AAA refused to tow it and he can get a better rate from someone on monday. I'll have to post an update if I figure something out or can update the status a little, thanks for the ideas/comments.

Well figured it out, it'll start because hee fuel pump is on at startup, then the fuel pump turns off after running for about 5 seconds. I have found that the fuel pump shut down relay is turning off the pump for some reason. If I bypass that relay it will stay running and runs fine. The OBD2 system give no codes. What would make this relay trigger a shutdown?

Thanks,
Paul

GOOD CATCH MY FRIEND! I BELIEVE IT IS BECASEU OF A RESISTOR IN THE FUEL PUMP RELAY AND/OR IN FUEL PUMP RELAY LOCATED ON PASSENGER SIDE BEHIND HEADLIGHT. GM MAKES REPLACEMNT KITS FOR IT. SEARCH POSTS ON THIS AWESOME GRAND PRIX BOARD. JOHN Z.

i HAD THIS VERY SMAE PROBLEM WITH MY1999 GT (3.8 NORMALLY ASPIRATED) AND IT TURNED OUT TO BE MY MAF IWTH NO CODES PRESENT. VERY FRUSTRATING. BUT WHEN I TRIED UNPLUGGING MAF, IT RAN BETTER, SO I REPLACED IT AND EVERYTHING IS NOW BACK TO NORMAL. THAT WAS AFTER CHANGING FUEL FILTER, FUEL RELAY, CLEANING THROTTLE BODY, CHECKING OF RVAUCCUUM LEAKS, CHECKING OFR ELECTRICAL PROBLEMS, CHECKING FUEL REGULATOR WITH $50 FUEL PRESSURE CHECK DEVICE AND A TOW. GRRRRR.