nurkvinny Posted November 29, 2008 Report Share Posted November 29, 2008 So, I have installed a used fuel pump assembly in my 02 Grand Prix GT, 3800, non-sc. No real improvement. Still starts, will still stay running as long as I hold the throttle up to 1400-1500. Won't maintain idle once I let off the gas. Continued from here. I think I have an old regulator from a Regal I can throw on next. Any other thoughts, now knowing it wasn't the pump? Quote Link to comment Share on other sites More sharing options...
AJ Posted November 29, 2008 Report Share Posted November 29, 2008 unplug the MAP sensor and see what happens, it nothing unplug the o2 sensor and see what happens. the nice thing about GM you can unplug and go into a preset and it will run better when you unplug the problem part. Quote Link to comment Share on other sites More sharing options...
nurkvinny Posted November 29, 2008 Author Report Share Posted November 29, 2008 Already unplugged the MAF, still ran just as poorly. Too loud to try anything else for the night. Quote Link to comment Share on other sites More sharing options...
AJ Posted November 29, 2008 Report Share Posted November 29, 2008 Already unplugged the MAF, still ran just as poorly. Too loud to try anything else for the night. not the MAF, the MAP. Quote Link to comment Share on other sites More sharing options...
nurkvinny Posted November 29, 2008 Author Report Share Posted November 29, 2008 Another small update, while under the hood unplugging and plugging in sensors, I smelled raw fuel. The fitting on the return line is leaking a small amount of fuel, maybe a drop every 10 seconds. Could a small leak on the return side cause this much of a headache? Is there just an o-ring I can replace? Quote Link to comment Share on other sites More sharing options...
dragknee66 Posted November 29, 2008 Report Share Posted November 29, 2008 I wouldnt think a leak on the return side would cause those problems.. but what about the fuel pressure reg.. I know the Grand Ams are prone to having shitty leaking and seizing ones. My buddy just had to replace one last week on his GA. Ive never had to deal with return lines on Pontiacs but Im assuming there is an oring probably. Quote Link to comment Share on other sites More sharing options...
excell Posted November 29, 2008 Report Share Posted November 29, 2008 A leak that small probably isn't the cause, but you know it's a problem so I would start there. There is an o-ring in the fuel line but I've never replaced it - I assume you can just fish it out and put in a new one. The lines are (really) cheap from Ed and terminate at the firewall just under the engine so it's easy to replace the whole thing. I think you have a vacuum leak and it could be internal. Where is this car, Vince? Quote Link to comment Share on other sites More sharing options...
dragknee66 Posted November 29, 2008 Report Share Posted November 29, 2008 Vac leak great possibility. The Orings you should be able to get at lowes or home depot too actually. We use to get orings for the DSMs there even. Quote Link to comment Share on other sites More sharing options...
nurkvinny Posted November 29, 2008 Author Report Share Posted November 29, 2008 I think you have a vacuum leak and it could be internal. Where is this car, Vince? This would not surprise me at all, it feels like a vacuum leak, but the external "starting fluid" spray test did not show an external one. The car's at my house, in Pataskala, near Rt 16 & 310. I have to renig on one thing I typed. The guy said the fuel filter had been replaced, but I just crawled underneath, and sure as shit, it says Delco and is rusty. The car also has a 160 stat, and the temp gauge never leaves the coldest reading, which is weird, even for a 160. Quote Link to comment Share on other sites More sharing options...
excell Posted November 29, 2008 Report Share Posted November 29, 2008 I don't think the filter is your problem, but what the hey - it's $7. Get the Delco replacement, not Autozone special. They don't filter or flow well. Get that 160 out of there. It's completely unnecessary and probably causing you gas mileage. Autozone carries a 180 for less than $10, it takes three minutes to replace. Too bad you're a little far out for me, I'd stop and figure it out but time is not on my side. Quote Link to comment Share on other sites More sharing options...
nurkvinny Posted November 29, 2008 Author Report Share Posted November 29, 2008 Stat is being replaced later today, NAPA Gold filter going on today, a stock exhaust is going on today (if this guy from Michigan ever shows up), working on getting a stock filter box. Going to clean the throttle body later also... going to eliminate things that need done anyway. Quote Link to comment Share on other sites More sharing options...
excell Posted November 29, 2008 Report Share Posted November 29, 2008 NAPA gold filters are okay. Better than that crap at the other stores. Quote Link to comment Share on other sites More sharing options...
Dave1647545494 Posted November 30, 2008 Report Share Posted November 30, 2008 those plastic intakes go bad all the time what kind of reading are you getting from the O2's on the scan tool? Quote Link to comment Share on other sites More sharing options...
nurkvinny Posted November 30, 2008 Author Report Share Posted November 30, 2008 Still haven't had the chance... had to stay close to home so far this weekend, the mrs. is having A LOT of contractions, and we've had a few more "false alarms". This freaking car is going on the back burner for a couple of days. (Did get a factory cat-back on this morning. God, these non-sc GT's sound horrible with dual Flowmasters.) Quote Link to comment Share on other sites More sharing options...
Dave1647545494 Posted November 30, 2008 Report Share Posted November 30, 2008 your pretty close to me if you want to swing by and borrow my scan tool Quote Link to comment Share on other sites More sharing options...
gmann Posted December 1, 2008 Report Share Posted December 1, 2008 those plastic intakes go bad all the time what kind of reading are you getting from the O2's on the scan tool? x2. also try using a propane torch that you don't have ignited while the cars running to see if RPMS increase, the starter fluid isn't as easy. Are you getting any fault codes? Quote Link to comment Share on other sites More sharing options...
nurkvinny Posted December 1, 2008 Author Report Share Posted December 1, 2008 No codes. I'll keep folks updated for giggles. The 'new' fuel pump made no real difference. The filter made no real difference. Unplugging each sensor 1 at a time showed nothing. All vacuum (exterior) looks great. Here's the coolest thing so far - putting a factory exhaust back on the car improved things noticeably. I'm thinking these cars (stock non-sc 3800's) enjoy having the factory back pressure. It also likes having the 195 stat back. Every step I take to put this thing back to factory makes it run, start, idle, etc better. I drove it tonight ~100 miles, and it purred like a kitten and got 31mpg. Still has an initial start up issue, but does not die out at lights any more. I Quote Link to comment Share on other sites More sharing options...
gmann Posted December 1, 2008 Report Share Posted December 1, 2008 so after it gets warmed up it will idle properly? Quote Link to comment Share on other sites More sharing options...
nurkvinny Posted December 1, 2008 Author Report Share Posted December 1, 2008 No, after it is running (at any temp) it will idle now. On every start up - cold or full temp - it dies out and you have to feather the throttle for 2-3 seconds to keep it running. Keep in mind, those are the symptoms right now, it has changed a little over the past week. Quote Link to comment Share on other sites More sharing options...
gmann Posted December 1, 2008 Report Share Posted December 1, 2008 Shit. That's weird, I give up. I suck at e-diagnose. Good luck man, if you weren't so far I'd offer to come take a look at it. Quote Link to comment Share on other sites More sharing options...
nurkvinny Posted December 1, 2008 Author Report Share Posted December 1, 2008 No worries, if it was my only car or DD, I would be spending more time on it. I did this for a living in one of my previous lives. The next step is to get this stupid K&N CAI off here (replacing w/ factory), and clean the throttle body. If anyone is following this epic Tech thread, all plugs were also checked, plug wires are aftermarket, the temp sending unit is working - verified now that the 160 stat is in the garbage. EGR is spotless. Once it's past the initial starting issue, it purrs and gets great MPG. Quote Link to comment Share on other sites More sharing options...
MrMeanGreen Posted December 1, 2008 Report Share Posted December 1, 2008 Wanna swap the CAI for a stock airbox setup? Quote Link to comment Share on other sites More sharing options...
nurkvinny Posted December 1, 2008 Author Report Share Posted December 1, 2008 Wanna swap the CAI for a stock airbox setup? I have a stocker lined up. I'll let you know if that deal falls through. Quote Link to comment Share on other sites More sharing options...
92dropgt Posted December 1, 2008 Report Share Posted December 1, 2008 fuel pressure reg been replaced at all? Quote Link to comment Share on other sites More sharing options...
nurkvinny Posted December 1, 2008 Author Report Share Posted December 1, 2008 fuel pressure reg been replaced at all? Not replaced, only checked for leaks. It was dry. On initial "key on", pressure gauge spikes to 53, but only for ~1 second, and then drops to near 40. My dad is looking for a used one off of one of the 3800's he's worked on, just for a quick test. Quote Link to comment Share on other sites More sharing options...
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