Spurlee Posted February 28, 2006 Report Share Posted February 28, 2006 The 1996 El Dorado (120,000) is starting hard but runs fine. Feels like a fuel problem so I did the FPR test and it seems good. (I'm assuming if it's bad the the leaking fuel is pretty obvious like drip, drip, drip...) It's a mild winter here and I'm running premium fuel. Plugs are new(ish) platinum ones and the wires look good but could probably be replaced next along with the fuel filter which might have 40K miles on it. Mileage is where it should be, low-to-mid 20's on average. I'm thinking it loses pressure in the rail after it sits for a while. No obvious signs of leaks up top. Could it be the fuel pump weakening? Scott Scott 1996 El Dorado 2006 STS 2000 Corvette Link to comment Share on other sites More sharing options...
MAC Posted March 1, 2006 Report Share Posted March 1, 2006 Check the Fuel Pressure Regulator. Link to comment Share on other sites More sharing options...
Ranger Posted March 1, 2006 Report Share Posted March 1, 2006 A bad FPR should leak when the vacuum line is removed, but not always. A hand held vacuum pump on the nipple will tell for sure. Pump it down and see if it holds vacuum. The other way would be to put a vacuum hose on it and suck. If you taste gas, it's bad. The check valve in the pump could be bad as well. Turn the key on but don't start for 3 seconds (pump shuts off after 3 seconds). Turn the key off and back on again for 3 more seconds. Then key off and normal start. That should be more than enough to reprime the system if it is leaking down. See if that makes any difference. Link to comment Share on other sites More sharing options...
PAUL T Posted March 1, 2006 Report Share Posted March 1, 2006 You might check for a leaky fuel injector. Pull the fuel rail and have someone pressurize the system by turning the key on and see if one of the injectors is leaking, they should not be. Link to comment Share on other sites More sharing options...
Spurlee Posted March 1, 2006 Author Report Share Posted March 1, 2006 A bad FPR should leak when the vacuum line is removed, but not always. A hand held vacuum pump on the nipple will tell for sure. Pump it down and see if it holds vacuum. Ranger: I'll put a vacuum on it and see. I have the replacement at hand. The very first time I cycled it I saw a blurp of fuel come out. I could never get it to do it again, though, so I figured it was OK. Maybe flawed logic on my part. I'll try priming the system as you suggest and see what comes of it. Scott 1996 El Dorado 2006 STS 2000 Corvette Link to comment Share on other sites More sharing options...
Ranger Posted March 1, 2006 Report Share Posted March 1, 2006 A bad FPR should leak when the vacuum line is removed, but not always. A hand held vacuum pump on the nipple will tell for sure. Pump it down and see if it holds vacuum. Ranger: The very first time I cycled it I saw a blurp of fuel come out. I think you have found the problem. Link to comment Share on other sites More sharing options...
PAUL T Posted March 1, 2006 Report Share Posted March 1, 2006 A bad FPR should leak when the vacuum line is removed, but not always. A hand held vacuum pump on the nipple will tell for sure. Pump it down and see if it holds vacuum. Ranger: The very first time I cycled it I saw a blurp of fuel come out. I think you have found the problem. Ditto that! No fuel should come out. Link to comment Share on other sites More sharing options...
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