95 Fleetwood LT1 Random Stalling / No Start
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5.0 and 5.7 Discussion, 95 Fleetwood LT1 Random Stalling / No Start in Cadillac Engine Technical Discussion; Hello, I need help with a stalling and restarting issue on my 95 Fleetwood Brougham, 62,000 miles. The car is ...
  1. #1
    fleetwdmax95 is offline Cadillac Owners Member
    Automobile(s): 95 FWB, 93 FWB, 83 CDV
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    95 Fleetwood LT1 Random Stalling / No Start

    Hello,

    I need help with a stalling and restarting issue on my 95 Fleetwood Brougham, 62,000 miles. The car is as pristine as they come and typically starts, runs, and drives flawlessly.

    I am recently having random stalling issues. After the vehicle is driven during my morning commute- 30 minutes/20 miles, then sits and is restarted, it will begin driving, then stall. It will turn over but not start. Occasionally, when pressing the accelerator to the floor, it will start, then die immediately. Once it has cooled (an hour or so), it will restart and run fine. If it is driven a short distance thereafter, it will stall again and not start. From what I can smell the car gets fuel when cranking. I get no check engine lights or subsequent codes.

    I have had much work done to the car, in what I thought was the potential problem as well as opti-issues, including:

    -Fuel system treatment
    -Fuel filter replacement
    -New Plugs and Wires
    -Fouled Injectors replaced
    -Water pump replaced
    -Opti-spark replaced (twice- original replacement went bad)
    -Alternator replaced (original alternator was charging at 14.5v. I thought this was high, and possibly the voltage regulators had gone bad, and a high charge was causing the ECM to shut off, but the new alternator also charges at 14.5v- is this normal?)
    -New Battery
    -New Ignition Module
    -Replaced harness cable between Opti and engine harness on top of manifold (these have been known to deteriorate under heat).

    I have seen numerous online posts from LT1 Camaro/Firebird/Impala owners, and have ruled out the Opti as a potential problem as it has been replaced. The next suggested routes seem to be:

    1.) Check IAC
    2.) Check for hot coil wire arcing
    3.) Clogged cat (should not be the case)
    4.) Check Fuel Regulator and Fuel Pump when hot
    5.) Test for Security or VATS failure when hot
    6.) Space the ICM from block with washers to keep cool, or replace altogether again
    7.) New O2 Sensor
    8.) Recheck all harness and pin connectors.

    Any further thoughts or suggestions would be an enormous help and timesaver.

    Thanks,

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  3. #2
    sven914 is offline Cadillac Owners Connoisseur
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    Re: 95 Fleetwood LT1 Random Stalling / No Start

    Heat sinking in the coils would be what I would look for. When the coils get hot, their internal resistance increases and they no longer send spark to the plugs. Heat sinking is a common problem in GM ignition coils, and the solution is replacing the coil.

  4. #3
    fleetwdmax95 is offline Cadillac Owners Member
    Automobile(s): 95 FWB, 93 FWB, 83 CDV
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    Re: 95 Fleetwood LT1 Random Stalling / No Start

    Yeah, I should have taken care of this before sending my panicked post, so I replaced the coil last night. Unfortunately on the way to work this morning in the pouring rain, it shut off again on the interstate after 10 minutes of driving. This time, though, it once again wouldn't start right away, but after a minute, it fired back up and made it home without instance. ???????? Here we go . . .

  5. #4
    sven914 is offline Cadillac Owners Connoisseur
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    Re: 95 Fleetwood LT1 Random Stalling / No Start

    The next thing I would do is check Fuel Regulator and Fuel Pump when hot and test the VATS. Everything else on your list would present other more noticeable drivability concerns.

  6. #5
    fleetwdmax95 is offline Cadillac Owners Member
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    Re: 95 Fleetwood LT1 Random Stalling / No Start

    Thanks,

    I'm working on this. Also, before I tear my dash apart, could you tell me where the ECM is located? There are some pins and connectors I would also like to test.

    Thanks again,

  7. #6
    sven914 is offline Cadillac Owners Connoisseur
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    Re: 95 Fleetwood LT1 Random Stalling / No Start

    I don't know where the computer is on your car. Someone on the RWD forum should know.

  8. #7
    fleetwdmax95 is offline Cadillac Owners Member
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    Re: 95 Fleetwood LT1 Random Stalling / No Start

    After all this I finally got it to throw a light. Code came back as distributor. Spoke with an LT-1 guy who told me you can NEVER use a reman'd or off-brand distributor which I did (twice). Replaced with a Delco from Summit and have had no problems.

  9. #8
    Stingroo's Avatar
    Stingroo is offline Wagon/Audio Enthusiast
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    Re: 95 Fleetwood LT1 Random Stalling / No Start

    Yeah, NEVER use an off-brand opti.

  10. #9
    harryj is offline Cadillac Owners Member
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    Re: 95 Fleetwood LT1 Random Stalling / No Start

    I have a 95 Cadillac Fleetwood with 125,000 miles that intermittently fails to start. The engine spins, but does not start, but if I wait 10 to 20 minutes and try again it will start. It has not failed to start after waiting, so mechanic can never determine problem, since he can't catch it when it doesn't start. The problem is completely random, I never know when it will happen. Another problem that may be related is that a few times it has cut off while driving, and started after waiting 10 to 20 minutes. The starter has been replaced twice, it has a new battery, and the ignition wire has been replaced.

    You seem to have had a similar problem. One of the posts on your query was:

    After all this I finally got it to throw a light. Code came back as distributor. Spoke with an LT-1 guy who told me you can NEVER use a reman'd or off-brand distributor which I did (twice). Replaced with a Delco from Summit and have had no problems.

    Did this solve the problem? My mechanic is willing to start throwing parts at it, but I am reluctant because I still won't know if it is fixed. Thanks for any suggestions.

    harryj

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