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Does fuel pressure regulator have a check valve?

danbeckdanbeck Posts: 3
edited April 22 in Oldsmobile
I have a 2000 Intrigue 3.5 with the FPR starting and stalling issues ! Takes 2 or 3 starts then runs down road perfectly. Ive read online that the test for a faulty FPR is to pull the vacumn line and see if it is wet with gas. I suppose a faulty diaphram would show this. Mine is dry the several times Ive checked it. I'm thinking if the regulator has a integral check valve to keep fulel from flowing back to fuel tank. This could be the problem. What do you think. The FPR tests good but sure seems to be faulty. thanks for ideas ! Dan

Comments

  • moonshadowmoonshadow Posts: 256
    Ive read online that the test for a faulty FPR is to pull the vacumn line and see if it is wet with gas. I suppose a faulty diaphram would show this.

    This only will tell you that the diaphragm is ripped and fuel is leaking pass and will be sucked into the intake manifold and cause a rich condition.

    A check value is at the outlet of the pump in the tank, however an improperly seating diaphragm will cause fuel to be bleed back into the tank through the return line and hence a drop in pressure. Another cause for pressure drop is through a leaky injector and you may be able to smell gas on the dipstick as the thin fuel will bleed by the rings into the crankcase.

    Apart from connecting a fuel pressure gauge and pinching off feed and return lines without exceeding 75 PSI, noting results and logically determining the cause, swapping in a new regulator on an educated guess work and probability may be your option.

    After sitting a bit, try cycling the key to on (not start) several times before you try a start. This will rebuild the pressure at the fuel rail and may prevent multiple crankings, as well as confirming that you do have a fuel pressure loss problem.

    cheers
  • dtownfbdtownfb Posts: 2,915
    Your starting issues may not be fuel related. My starting problems behaved exactly what you are describing and it ended up being a bad ignition switch. My issues started back in January and finally got to the point in June that I had to replace the ignition switch.
  • danbeckdanbeck Posts: 3
    Thanks for your well thought out replies ! I had read before of some strange driveability problems with this car that turned out to be ignition switch. I have it in my shop this morning to change out plugs and boots at 104K miles. I dont think thats the problem, but it is time for new plugs at the price of fuel. Their going to run their diagnostic program, but Im doubtful anything will show up ! When I took it in, it started like not a thing was wrong with it, Just my luck ! Thanks Dan
  • dtownfbdtownfb Posts: 2,915
    I've never seen an ignition switch cause so many problems. For a while I thought my issue was fuel related as well. Then I thought the crankshaft position sensor was going bad. It never threw a code which made me focus on the ignition switch. Eventually it was taking me 10-15 tries to get the car started.

    Let's hope all stays well with your car.
  • danbeckdanbeck Posts: 3
    The shop didnt find a thing wrong on diagnostics and of course it didnt fail today either so I'm plainly out $100. Im going to replace the ignition switch and have the instructions you had posted on the process ! Did you need to replace the cylinder also or just the switch. What should I look for on the cylinder that may show it needs replacement and also is anything evident on the switch indicating it is faulty?
    Did you order yours online ? Wheres a good source ? Any other information you can provide on the replacement I am sure grateful for ! Dan
  • dtownfbdtownfb Posts: 2,915
    You re-use the tumbler in the new switch. You can try cleaning the electrical contact on the outside. Use electrical connector cleaner. they sell it at auto part stores. Mine were fine but others had reported that simply cleaning the contacts worked for them. they also reported that the contacts looked dirty with "residue". After cleaning the contacts, you can try starting it to see if it works (re-connect the negative cable and the connectors) and return the new switch. If it doesn't work, you have the new switch there. Also test that as well. I also tried spraying WD-40 into the tumbler but didn't work.

    My ignition switch was made by Standard. I bought it from Federated Auto parts (cost just over $100). You can do online (www.rockauto.com or www.gmpartsdirect.com), but I needed the switch that day since I was leaving town the next morning. There are cheaper ones at Auto Zone and Advance Auto parts. The guy at Federated said that he could order me a cheaper ones but they were flimsier. Who knows? The price I paid at Federated was cheaper then at Advance Auto Parts.

    The worst part about the entire process was getting the switch from behind the dashboard into the open (the last steps) and putting the switch back into the dash. You can't see well and it is tight quarters. It may have more to do with my big hands. Pay attention to the directions. The person who provided these directions did a nice job on commentary. I would also use this opportunity to replace any instrument cluster bulbs that may have blown. When you remove the instrument cluster, push it in (slightly) and pull the bottom out first. And don't forget the steering wheel tilts.

    It will take you about an hour and a half to do it. I had to do it twice (this is part of the reason I had to buy at an auto part store).

    Good luck and I hope this works. I think the fact that you did have a diagnostic done and nothing was found leads you to the ignition switch. The only other thing it could be is a bad battery connection but that would show up in other areas.
  • I have an 03 Mitsubishi Galant that has me at my wits end, i've been working on it for two weeks now and replaced the fuel pump, fuel filter and checked the fuel lines but I still can't get the car to start. I'm beggining to wonder if it has something to do with the ignition switch, will the car still try to start if the switch is faulty?
  • dtownfbdtownfb Posts: 2,915
    Not familiar with the Galant but the only thing you have left to check in the fuel system is the fuel pressure regulator.

    It depends on how bad the ignition switch is. When mine went bad, whenever I turned the key, the lights (radio, "check engine", etc.) would light like normal but nothing would happen. this could happen 2 or 3 times, sometimes 12 to 15 times before it finally started. I also had a couple of incidents when the car stalled while driving. Also had a time when the "security" light flashed on and the car stalled.
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