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Thread: Fuel Problem

  1. #1
    Full Throttle Firebird95driver's Avatar
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    Fuel Problem

    Here's the scoop:
    I made a thread earlier regarding the relay wiring because I thought this was the culprit to my car's starting issue, as it would start and immediately shut off then start and stay on at the second time usually. It ended up taking a dump while trying to leave the library last week and wouldn't come on at all. My buddy and I pushed it to try and pop it into gear but it would just vroom once and shut off. I wasn't able to hear the pump prime so I figured the pump was the issue.
    A trap door later and it turns out the old pump was fine after I hit it with 12v directly, but I had already gotten a new one so I put that one in instead. I go to fire it up, hear it prime, and nothing.
    Then I changed the fuel filter which I hadn't done previously.
    Again nothing, despite hearing the pump prime.
    So now I have spent the last two days doing checks. The Schrader valve sees no pressure. I keep priming it with the gray wire and tried checking the Schrader with 12v on the prime connector and still nothing, even though I can hear the pump running.
    Then, I dis connect the IN side of the filter from the tank and try running the pump. Nothing comes out. So I take the 12v off and about a minute later, fuel starts coming out of the disconnected line even with the pump OFF.
    There is pressure in the tank as well (i can hear it hiss when unbolting the 5 murres) and when disconnecting the line out of the tank, there is fuel. Do I have a case of a clogged line? Pinched? As far as I can see the lines look OK.
    My next check is to put the old pump back in and see if it works. But this ordeal is really bumming me out.

    95 Firebird 3.4L V6.
    5-speed. Flowmaster muffler. CAI. Underdrive crank pulley. !A/C. TB Coolant Bypass. Holley Adjustable FPR. Proshaft One-piece Aluminum Driveshaft. So it's pretty much stock.
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  3. #2
    Half Throttle
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    If you're not getting any fuel pressure at the rail, even with a new pump and filter, then it would have to be the lines IMO. Try investigating the rubber return lines. I did a search online and below are a couple posts from other car guys who also had a good pump, but no fuel pressure:

    "Plug or crimp off the return line and see if you get any pressure, FPR might be sticking open.
    My 91 when I bought it had sat in a barn for about 5 years, when I went to crank it the fuel pump would run but no pressure. The rubberline in the tank on the pump had busted."

    "I've dealt with the bad rubber lines too. Amazing how sticky the rubber gets."

  4. #3
    Full Throttle Firebird95driver's Avatar
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    I've got pressure in the front now (don't even ask where I bucked up it is terrible).
    Now it kicks up vroom! once, but goes right off. My buddy is suggesting plugs. I am still googling...

    95 Firebird 3.4L V6.
    5-speed. Flowmaster muffler. CAI. Underdrive crank pulley. !A/C. TB Coolant Bypass. Holley Adjustable FPR. Proshaft One-piece Aluminum Driveshaft. So it's pretty much stock.
    -Wishlist-
    *Twin Turbos*
    *6-speed Trans*
    My Music- firebird95driver.bandcamp.com
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  5. #4
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    Good to hear that you now have fuel pressure! Sounds like you may have flooded the engine or fouled the plugs. You could pull the easiest plug to get to and find out where to go from there!

  6. #5
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    You could also floor the gas pedal while starting the engine which will turn off the fuel injectors so you can help unflood the engine(if it's flooded). Or pull the injector fuses works as well.

  7. #6
    Full Throttle Firebird95driver's Avatar
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    Thanks for the input koolcamaro,
    I just got up and am gonna check the plugs to start.

    95 Firebird 3.4L V6.
    5-speed. Flowmaster muffler. CAI. Underdrive crank pulley. !A/C. TB Coolant Bypass. Holley Adjustable FPR. Proshaft One-piece Aluminum Driveshaft. So it's pretty much stock.
    -Wishlist-
    *Twin Turbos*
    *6-speed Trans*
    My Music- firebird95driver.bandcamp.com
    Daniel

  8. #7
    Full Throttle Firebird95driver's Avatar
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    I couldn't upload it into here since I am using my tablet but here's the link to a picture of one of the plugs. It did smell like fuel.
    https://www.instagram.com/p/BH7hfVBhOkt/

    95 Firebird 3.4L V6.
    5-speed. Flowmaster muffler. CAI. Underdrive crank pulley. !A/C. TB Coolant Bypass. Holley Adjustable FPR. Proshaft One-piece Aluminum Driveshaft. So it's pretty much stock.
    -Wishlist-
    *Twin Turbos*
    *6-speed Trans*
    My Music- firebird95driver.bandcamp.com
    Daniel

  9. #8
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    Sorry for the late response, but yeah those are definitely fouled lol. You could try cleaning them or just replace them so long as the original issue was fixed which i believe to be the case.

  10. #9
    Full Throttle Firebird95driver's Avatar
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    I put the new plugs in just now and I am still getting the same issue. It fires up but dies immediately after the initial rev. I am thinking it is a coil problem but I'll have to pick up an HEI tester to be sure.

    95 Firebird 3.4L V6.
    5-speed. Flowmaster muffler. CAI. Underdrive crank pulley. !A/C. TB Coolant Bypass. Holley Adjustable FPR. Proshaft One-piece Aluminum Driveshaft. So it's pretty much stock.
    -Wishlist-
    *Twin Turbos*
    *6-speed Trans*
    My Music- firebird95driver.bandcamp.com
    Daniel

  11. #10
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    Put a fuel pressure gauge on the fuel rail and see what your fuel pressure is. You could have low fuel pressure or no pressure after the priming. I had a similar problem that ended up be the fuel pump relay. Although it still worked the contacts were so burnt up it was causing low voltage to the pump.

  12. #11
    Full Throttle Firebird95driver's Avatar
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    I've got the Holley FPR and set it to 45psi this morning. I'll try swapping the relay with the trunk one. To bypassthe relay, could I put 12v on the prime connector and leave it there while I crank the engine? Or would that cause a current overload?

    95 Firebird 3.4L V6.
    5-speed. Flowmaster muffler. CAI. Underdrive crank pulley. !A/C. TB Coolant Bypass. Holley Adjustable FPR. Proshaft One-piece Aluminum Driveshaft. So it's pretty much stock.
    -Wishlist-
    *Twin Turbos*
    *6-speed Trans*
    My Music- firebird95driver.bandcamp.com
    Daniel

  13. #12
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    You said you had fuel pressure at the rail right? Three things you need for a car to run are fuel, air, and spark. So if you are showing fuel pressure, then you could check the other two. Next would be spark which you can do by removing a spark plug from the head, attach it to the spark plug wire, then turn the engine over and see if you have spark. You could do this for every spark plug and wire to make sure all your coils are good to go. At this point, if your fuel and spark is good then your next step would be checking air which would be with a compression test.

    I'm not trying to insult your intelligence if you already knew all of this, but it's always good to go back to the basics. A good example would be me trying to fire up my 3.4/3500 for the first time after my fresh rebuild. It would not start no matter what I did and I thought it was an engine ground issue. So I checked fuel which was good, spark was good, but no compression. I later found out that I bent all my brand new SS exhaust valves because I lined the dots wrong on the timing chain set. Just an example where going back to the basics can help. It should at least narrow it down to one of those three areas anyways. Keep us updated!

  14. #13
    Full Throttle Firebird95driver's Avatar
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    Thanks for the tips. I got myself an HEI tester for the plugs and didn't see spark from one coil. I went ahead and replaced it, am getting spark, but still no running car. My next step is to take the battery to be charged and get the alternator checked. If it turns out it was the alternator all along, then THAT will be an insult to my intelligence... and I am getting the feeling the alternator was at fault all along.

    95 Firebird 3.4L V6.
    5-speed. Flowmaster muffler. CAI. Underdrive crank pulley. !A/C. TB Coolant Bypass. Holley Adjustable FPR. Proshaft One-piece Aluminum Driveshaft. So it's pretty much stock.
    -Wishlist-
    *Twin Turbos*
    *6-speed Trans*
    My Music- firebird95driver.bandcamp.com
    Daniel

  15. #14
    Full Throttle Firebird95driver's Avatar
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    ... still nothing.

    EDIT: After reading up a bit, I am thinking it is the ICM or cam sensor. ICM makes sense as the middle coil wasn't shooting (though I replaced it)
    Last edited by Firebird95driver; 07-20-2016 at 10:40 PM.

    95 Firebird 3.4L V6.
    5-speed. Flowmaster muffler. CAI. Underdrive crank pulley. !A/C. TB Coolant Bypass. Holley Adjustable FPR. Proshaft One-piece Aluminum Driveshaft. So it's pretty much stock.
    -Wishlist-
    *Twin Turbos*
    *6-speed Trans*
    My Music- firebird95driver.bandcamp.com
    Daniel

  16. #15
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    Your local parts store(autozone, oreillys, etc) should be able to test your ICM. I've had a bad cam sensor before and the camaro still ran, just had a weird idle and bad gas mileage. There is a way to to test the cam sensor http://troubleshootmyvehicle.com/gm/...e-cam-sensor-1

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