dodgethis Posted February 12, 2009 Report Share Posted February 12, 2009 Just as the topic says. I noticed everytime when i let the car sit for an hour its hard to freaking start the thing. I figure its the fpr. I am curious as to how hard is it to replace on a 3100 and does it actually hurt the gas mileage on the car? Quote Link to comment Share on other sites More sharing options...
ns87 Posted February 12, 2009 Report Share Posted February 12, 2009 I think the FPR is either broken or working. Idk much about 3100s, but if it has a vacuum line on it and fuel is pouring out of that line, its broken. Quote Link to comment Share on other sites More sharing options...
carkhz316 Posted February 12, 2009 Report Share Posted February 12, 2009 Think there was thread about this awhile back, but yes, a bad one will cause bad mileage and crappy starting as it will be running overtly rich. 18in. vacuum on one side, 45psi on the other side, separated by a rubber diaphragm, when it ruptures, it hoooovers gas. As a temp fix, you can cap the end of the "nipple" on the FPR, and plug the vacuum line, which will at least stop it from running like crap, but optimaly, get it replaced. I think it's just a screw/ bolt that holds it to the end of the fuel rail, someone correct me if I'm wrong, and may or may not require ripping the upper plenum off. I can't remember exactly. Quote Link to comment Share on other sites More sharing options...
jerry455 Posted February 12, 2009 Report Share Posted February 12, 2009 whne it ruptures you get fuel pressure into the vac. lines. happened monday, could'nt start car. the intake duct between my intercooler and throttle body had fuel sitting in it when i removed it. it started to go last weekend, it was taking a long time to start. it would crank for several seconds before it would start and then it would sputter like when 2 years ago when i had 2 bad injectors. finally on monday afternoon while diagnosing it i found the vac. lines had fuel in them, i pulled the rail out of the intake and then turned on the key and fuel was shooting out of the vac.port of the regulator. i have a 90 tgp and the delco part was $122.50, was fairly easy to repair. Quote Link to comment Share on other sites More sharing options...
carkhz316 Posted February 12, 2009 Report Share Posted February 12, 2009 Why are they soooooo seemingly expensive, or am I the only one who thinks that. For how simple the part is, it costs a buttload Quote Link to comment Share on other sites More sharing options...
mfewtrail Posted February 13, 2009 Report Share Posted February 13, 2009 Those late 90's/early 2000's 3100's develop leaky injectors pretty commonly. If you don't find fuel in the vacuum line for the FPR, then your injectors are most likely leaking. When they leak, they're pissing fuel into the engine and soaking the plugs. This makes for hard cold starts or after sitting a while. You can put a fuel pressure gauge on the test port at the rail and see how quickly your pressure bleeds off. It will drop pretty quickly if you have some leaking. Besides that, if you feel like doing some wrenching, you could remove the plenum, unbolt the rail and pull it up, leaving the fuel lines attached. Then pressurize the rail by turning the key to the on position and then check for leaks. Placing blue shop paper towels underneath the injectors will make the leaks very obvious. Your oil will also smell very strongly of gasoline if the injectors are leaking. Quote Link to comment Share on other sites More sharing options...
dodgethis Posted February 13, 2009 Author Report Share Posted February 13, 2009 thanks for the post guys. I will get a fuel pressure gauge and hook it up to the schrader valve to see what the pressure is looking like. I want to say also that every time when i do start the car after it has sit for a few hours I am trained to also push on the gas pedal for it to actually start. I know if i don't use the gas pedal then it will take about 5 seconds longer on the starter for it finally fire. I guess that is all indications about a bad FPR. I will also check the oil to see if it has a distinct smell of gas in it. That's a bummer thought that one has to pop off the plenum to get to the FPR. When the plenum is taken off the gasket around it has be replaced every time its taken off right? Quote Link to comment Share on other sites More sharing options...
AL Posted February 13, 2009 Report Share Posted February 13, 2009 Try the vacuum line thing first... Just pull the vacuum line off the FPR and see if it squirts gas... Quote Link to comment Share on other sites More sharing options...
jerry455 Posted February 14, 2009 Report Share Posted February 14, 2009 autozone had a generic for $85 but i like to use delco when i can, besides my tgp's engine is less than a year old. i am going to try and increase the power from this car so i wanted an original equipment part. hopefully it is better quality,the original lasted 19 years. Quote Link to comment Share on other sites More sharing options...
dodgethis Posted February 14, 2009 Author Report Share Posted February 14, 2009 Try the vacuum line thing first... Just pull the vacuum line off the FPR and see if it squirts gas... Man this is a real noob question. Where is the vacuum line you speak of? If i was facing the engine bay where would it be sittin? I think its over on the passenger side maybe or is it some where near the throttle body on the driver side? Thats a clue for me to look for Quote Link to comment Share on other sites More sharing options...
dodgethis Posted February 25, 2009 Author Report Share Posted February 25, 2009 Try the vacuum line thing first... Just pull the vacuum line off the FPR and see if it squirts gas... Hey I found the FPR on the 3100. This is a stupid question but bear with me. Do i need to relieve fuel pressure to pop off the vacuum line? The next question is, is this done with the engine off? I didn't know so I thought id ask... Old thread i know, school has just wore me out. I am just now getting to the car. Quote Link to comment Share on other sites More sharing options...
Addicted To Boost Posted February 25, 2009 Report Share Posted February 25, 2009 Try the vacuum line thing first... Just pull the vacuum line off the FPR and see if it squirts gas... Hey I found the FPR on the 3100. This is a stupid question but bear with me. Do i need to relieve fuel pressure to pop off the vacuum line? The next question is, is this done with the engine off? I didn't know so I thought id ask... Old thread i know, school has just wore me out. I am just now getting to the car. No, you do not need to relieve fuel pressure when popping off the vacuum line only. This is done with the engine off. Quote Link to comment Share on other sites More sharing options...
AL Posted February 25, 2009 Report Share Posted February 25, 2009 I was told you can do it either way, off or on... Both ways will shoot out gas if I am not mistaken Quote Link to comment Share on other sites More sharing options...
dodgethis Posted February 25, 2009 Author Report Share Posted February 25, 2009 I was told you can do it either way, off or on... Both ways will shoot out gas if I am not mistaken Gonna Sh*T a brick if i pull that vacuum line with the engine off and i find fuel in there. I swear my lumina was doing good without even a check engine light on. When class lets out tonight i'll pull it out. I figure if its in the vacuum line it will be waiting for me at 8:00pm. P.I.T.A to get it to start sometimes. Love the car though.... Quote Link to comment Share on other sites More sharing options...
AL Posted February 26, 2009 Report Share Posted February 26, 2009 I asked my teacher today... He said do it with the car running Quote Link to comment Share on other sites More sharing options...
dodgethis Posted February 26, 2009 Author Report Share Posted February 26, 2009 I asked my teacher today... He said do it with the car running Good to know, I haven't checked it yet. I left campus at 2am. When i get to work today ill let you guys know what I find. Quote Link to comment Share on other sites More sharing options...
dodgethis Posted February 26, 2009 Author Report Share Posted February 26, 2009 Hey i checked the valve. There was no fuel in the line. I guess its doing its job like its supposed to by pulling a vacuum through the line to the regulator. I hate that, I was hoping i could fix something new and add to my list of stuff fixed on my own. Oh well, I couldn't think what could make the hard starts on the car. Quote Link to comment Share on other sites More sharing options...
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