94 STS, Starts up, Shuts off, no useful codes, not security system - Page 2
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Cadillac Seville / Cadillac Eldorado Forum Discussion, 94 STS, Starts up, Shuts off, no useful codes, not security system in Past Cadillac Vehicle Discussion; Tankboy is right, it's a 4.6, that was my mistake, not a 4.9.. It is definitely a N* though, unless ...
  1. #16
    TooManyCars is offline Cadillac Owners Member
    Automobile(s): 94 Seville STS, Bradley GT/68 Ghia, 85 Fiero GT, 88 V8 Comma
    Join Date
    Apr 2013
    Location
    Henrico, VA
    Age
    35
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    Re: 94 STS, Starts up, Shuts off, no useful codes, not security system

    Tankboy is right, it's a 4.6, that was my mistake, not a 4.9.. It is definitely a N* though, unless someone just put an N* decals all over the car.

    ----------

    I figured out my fuel gauge problem, turns out the gauge is a cheap piece of crap. I was able to get a reading though.

    When I turn the key forward and let the pump prime, it primes to about 45 PSI. After it primes it starts dropping rapidly, after probably 10 seconds it is down to 20 psi (this may also be due to the gauge??).

    When I start it up the pressure is constant about 45 PSI or so. After the car dies, I hear a faint whirring near the throttle body for about 5~10 seconds, once that whirring stops, the pressure begins to drop again as it did when I turned the key but did not start the car.

    For what its worth, the problem with the gauge was that the pin that pushes in the sharder valve pin, was made out of what appears to be stamped brass and is very soft. Instead of pushing the shrader valve pin in, it bent and was sliding in next to it, and of course not letting any fuel out.

    I am beginning to wonder if there are more than 1 symptoms of the security system fault. I say that mainly because the symptom I am seeing is almost exactly what many GM cars do when the resistor key security system has a fault, but I am perplexed because as stated above, I get a clear and present security fault warning when I purposely fault the key.

    Thanks again for all of your input guys/gals!

  2. #17
    Ranger's Avatar
    Ranger is offline Cadillac Owners Member
    Automobile(s): White Diamond '03 DHS (with floor shift)
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    Re: 94 STS, Starts up, Shuts off, no useful codes, not security system

    Quote Originally Posted by TooManyCars View Post
    When I turn the key forward and let the pump prime, it primes to about 45 PSI. After it primes it starts dropping rapidly, after probably 10 seconds it is down to 20 psi (this may also be due to the gauge??).
    That sounds like a bad check valve at the pump.

  3. #18
    TooManyCars is offline Cadillac Owners Member
    Automobile(s): 94 Seville STS, Bradley GT/68 Ghia, 85 Fiero GT, 88 V8 Comma
    Join Date
    Apr 2013
    Location
    Henrico, VA
    Age
    35
    Posts
    9

    Re: 94 STS, Starts up, Shuts off, no useful codes, not security system

    I am researching the check valve issue at the moment, I will post an update once I have found something more. I am going to resolve this issue so its right, but am curious, might a bad check valve cause my shut-down symptom or does it typically manifest itself as hard starts? I ask because I don't want to put any money in this car that isn't fixing it, until I know I can get it running fine - I am not trying to cut corners.

    In the meantime, I got a third hand and was able to have the car started while I watched the fuel pressure gauge. It primes to about 42~45 PSI, then starts and sits at about 36~37 while running, then it jumps back up to 42+ a second or so before it dies, but while it is still running smoothly.. Is it possible that the injectors are being cutoff for some reason causing higher fuel pressure at the rail just before shutoff?

    We're getting close, I can feel it.. She asked me this morning when I was going to take her out for burgers.. I said soon baby.. soon... Thanks again for all of the input!

  4. #19
    Ranger's Avatar
    Ranger is offline Cadillac Owners Member
    Automobile(s): White Diamond '03 DHS (with floor shift)
    Join Date
    Jun 2004
    Location
    Woodstock Ill.
    Age
    66
    Posts
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    Re: 94 STS, Starts up, Shuts off, no useful codes, not security system

    Your fuel pressures sound OK. Mine idles at 38. The check valve prevents drain back after shutdown for quick starts. It shouldn't cause a shut down though, unless of coarse the pump itself is intermittent.

  5. #20
    TooManyCars is offline Cadillac Owners Member
    Automobile(s): 94 Seville STS, Bradley GT/68 Ghia, 85 Fiero GT, 88 V8 Comma
    Join Date
    Apr 2013
    Location
    Henrico, VA
    Age
    35
    Posts
    9

    Re: 94 STS, Starts up, Shuts off, no useful codes, not security system

    Can someone please verify if these are the correct FSM books I should buy?

    http://www.ebay.com/itm/1994-CADILLA...993396&vxp=mtr

    They are asking $90, is that a fair price? What should I offer?


    Thanks in advance!

  6. #21
    Ranger's Avatar
    Ranger is offline Cadillac Owners Member
    Automobile(s): White Diamond '03 DHS (with floor shift)
    Join Date
    Jun 2004
    Location
    Woodstock Ill.
    Age
    66
    Posts
    70,310

    Re: 94 STS, Starts up, Shuts off, no useful codes, not security system

    Those are the correct manuals. I'd offer $45.

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