FPR replaced, bad cold starts
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Cadillac Seville / Cadillac Eldorado Forum Discussion, FPR replaced, bad cold starts in Past Cadillac Vehicle Discussion; The Car: 1992 Seville, 4.9L PFI I recently replaced my fuel pressure regulator. It had a ruptured diaphram which caused ...
  1. #1
    Zynder is offline Cadillac Owners Member
    Automobile(s): 1992 Seville 4.9L 230k+ miles
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    FPR replaced, bad cold starts

    The Car: 1992 Seville, 4.9L PFI

    I recently replaced my fuel pressure regulator. It had a ruptured diaphram which caused perfect cold starts but vapor locking issues when trying to hot start. Once I replaced the FPR, as expected, I now have perfect hot starts but the cold starts are excessive. 30 seconds or more of continuous cranking and sometimes multiple bursts. This excessive cranking has already killed what was probably a mostly worn out battery. As you all may also know this excessive cranking can overheat the starter which I really don't want to do.


    So which area(s) should I concentrate my search to restore perfect cold starts? I am showing no codes other than the suspension ones from bad air shocks(unrelated). Also, and this may be unrelated I'm not sure, when you turn the engine off, the idle solenoid does that clicking racket where it pops in and out rapidly for about 20 secs after shutdown. I would like to fix that as well.

    I have already replaced the spark plugs, wires, & ignition module recently. The fuel filter is on my to-do list. The engine runs beautifully otherwise, just takes too much cranking to start.

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  3. #2
    Ranger's Avatar
    Ranger is offline Cadillac Owners Member
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    Re: FPR replaced, bad cold starts

    Override the ISC motor by cranking it with very slight pressure on the accelerator to hold the throttle plate open a bit. If that does not help, check your fuel pressure.

    P.S.
    That was not a vapor lock that caused your hard starts. It was an overly rich condition. Like trying to start a hot carbureted engine with the choke engaged.

  4. #3
    Zynder is offline Cadillac Owners Member
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    Re: FPR replaced, bad cold starts

    Oh yeah it was overly rich! So rich it would lock the engine up so bad the starter couldn't crank it over until I let it sit and cool down. Works great now though except the excessive cranking. I will adjust the ISC and verify the throttle plate is adjusted properly. I think I may pull the TB and give it a soak in some Berryman as well. I doubt it has ever been cleaned.

  5. #4
    Ranger's Avatar
    Ranger is offline Cadillac Owners Member
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    Re: FPR replaced, bad cold starts

    Whoa! "Lock the engine up so bad the starter couldn't crank it over"? That sounds like a hydrolock. Consider yourself lucky that there was no major damage.

  6. #5
    Zynder is offline Cadillac Owners Member
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    Re: FPR replaced, bad cold starts

    Yeah. hydrolock, vaporlock is use them synonymously. I am surprised the damned thing didn't catch fire. It was leaking so much fuel through there it ate the vacuum line apart and was puddling gas right there on the intake. The problem was I had a power steering reservoir o-ring leak as well and the manifold was also full of PS fluid so you couldn't really tell the difference. I found the fuel leak while I was cleaning up the PS leak. Lucky me

  7. #6
    Aztec ETC ECS's Avatar
    Aztec ETC ECS is offline Cadillac Owners Connoisseur
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    Re: FPR replaced, bad cold starts

    Sounds like a possibly defective new FPR, allowing pressure to bleed off overnight.

    Also all that excessive fuel could have damaged the MAP sensor. Should run poorly all the time but I can't really think off anything else.

  8. #7
    Zynder is offline Cadillac Owners Member
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    Re: FPR replaced, bad cold starts

    Good point. I'll let it sit awhile and push the schrader valve in to see if it has held pressure, thanks!

  9. #8
    Ranger's Avatar
    Ranger is offline Cadillac Owners Member
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    Re: FPR replaced, bad cold starts

    Even if it does bleed off overnight, pressure should be right at 40 (or thereabouts) within a second or two of key on.

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