Ceramiclover Posted April 28, 2015 Share Posted April 28, 2015 (edited) Sorry to start a recurring topic, but was looking for some guidance on some key points. Typically: Vehicle cranks endlessly. 2nd attempt (after total of 10 seconds or more of cranking), vehicle starts. Vehicle starts if you put the pedal on the floor, stumbles for a second (gas it), and then runs fine. So far, I have: replaced fuel filter spark plugs ECTS seems to read accurately (I read data list from a Techstream) Disconnected MAF sensor, performed about the same. Someone suggested that an injector could be leaking, so I pulled up both fuel rails and cycled ignition to see if any fuel dripped. None did. II put a fuel pressure gauge on the inlet to the fuel filter. Priming the pump and with engine running is around 35PSI. With key off, pressure drops to 0 within 2 minutes. Is this part of the problem? I have never diagnosed a fuel issue before. I know there have been some issues with the cap and the O ring at the fuel pump. Is there something I should look for? Should I try a junkyard pump? Edited April 28, 2015 by Ceramiclover Quote Link to comment Share on other sites More sharing options...
lstevens76 Posted April 28, 2015 Share Posted April 28, 2015 Your pressure shouldn't be dropping off like that I don't believe. Most cars retain the pressure long after it's off. I would suspect a leak somewhere causing it to drain off pressure. Quote Link to comment Share on other sites More sharing options...
Ceramiclover Posted April 28, 2015 Author Share Posted April 28, 2015 Are you talking about vapor or an actual gas leak? Quote Link to comment Share on other sites More sharing options...
lstevens76 Posted April 28, 2015 Share Posted April 28, 2015 Dropping that fast after the car isn't running would probably be a fuel leak somewhere. A stuck open injector, or 2, could do it without smelling it. Your getting no CEL? Quote Link to comment Share on other sites More sharing options...
Ceramiclover Posted April 28, 2015 Author Share Posted April 28, 2015 No CEL. I replaced the fuel filler neck, because it was leaking. The new one came of an impreza and was slightly different. I think we just capped off an extra vapor hole or something. i don't see fuel leaking anywhere, though. Quote Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted April 28, 2015 Share Posted April 28, 2015 pretty sure that system should maintain pressure more than 2 minutes. Plus the fact that holding the pedal to floor seems to point to a leaking injector. maybe cycle the key to ON, wait for the FP to run, OFF, wait 2 mins, -ON, -OFF, wait 2 mins, then pull plugs to see which one is wet? Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted April 28, 2015 Share Posted April 28, 2015 Pressure loss isn't a big deal if it takes 2 minutes. The pressure build is what you should be concerned with. After the pressure drops off, crank the engine and watch for the pressure to build. It should be almost instant right back to 35 psi. If it takes 10-15 seconds of cranking to restore fuel pressure, you probably need a new pump. Another thing that's quick and easy to check is the vacuum hose going to the pressure regulator. At the end of the rail on the passenger side. Pull the vacuum hose off and see if gas drips out. If it does, you need a new regulator. Extended cranking time is usually due to a fuel issue, but just to make sure things are up to par, how old are the spark plugs, filters, PCV valve? Pump assembly Cap and o-ring problem are only on 2000-2004 models, so you've nothing to be concerned with as far as that goes. Quote Link to comment Share on other sites More sharing options...
Ceramiclover Posted April 28, 2015 Author Share Posted April 28, 2015 Pressure builds instantly. Fuel filter and air filter are good. Spark plugs are new. PCV could have been old. This is a rescue Sub (like a puppy) I got from the impound lot. It seems like it sat for awhile. Will check PCV and regulator vacuum hose. Quote Link to comment Share on other sites More sharing options...
Cougar Posted April 29, 2015 Share Posted April 29, 2015 There should be a check valve in the fuel pump to keep the fuel from back flowing to the tank. How does the engine start if you shut it off and try to restart it 15 minutes later? If it takes some time then you may need to replace the pump. Another thing you might check to see is how the engine reacts and starts up cold after spraying a small amount of starter fluid into the intake. Quote Link to comment Share on other sites More sharing options...
Ceramiclover Posted April 29, 2015 Author Share Posted April 29, 2015 I put in a junkyard regulator. Pressure now remains at 30PSI after key off. I waited 30 minutes. Pressure was the same. Started right up. I'll keep checking it, but it seems like that did the trick. Thanks for everybody's input. Not much experience in this area. Took me over an hour to get the harbor freight pressure gauge not to leak. Quote Link to comment Share on other sites More sharing options...
Cougar Posted April 29, 2015 Share Posted April 29, 2015 Glad to hear you got it fixed and thanks for the update. It sounds like there may be check valve in the regulator that was allowing pressure to release back to the tank area. Quote Link to comment Share on other sites More sharing options...
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