1995 STS hard start and stall problem
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Northstar Engines and System Technical Discussion Discussion, 1995 STS hard start and stall problem in Cadillac Engine Technical Discussion; Well I took advantage of a warm winter day and cleaned under the hood of the car, nothing crazy just ...
  1. #1
    mdegracia is offline Cadillac Owners Member
    Automobile(s): 1995 STS
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    1995 STS hard start and stall problem

    Well I took advantage of a warm winter day and cleaned under the hood of the car, nothing crazy just hosed off the under hood area..avoiding contact with the electronics directly. I did not start the car up after, which in hindsight, I should have.

    1995 STS 120k
    I have replaced FPR and cleaned the TB. Car has been temperamental to start sometimes, even after the FPR replacement, but not the less, the car has been running and in use up until the cleaning....

    So I went to start the car this morning and it fluttered and then stalled completely. Went to start again and then it sputtered and did not start at all. Tried again , while giving gas, and it started - let my foot off and it stalled. Tried again with gas, and slowly let my foot off the gas after a few minutes of "forced" idling and it stayed running. Went to give it gas in neutral and it stalled. I did this process a few times and then eventually got it in gear R and D, but stalled in D, so I stopped.

    Codes were p026, p070, and p095. Looked those up and one is the TPS and the other is TPC ( part of the ISC)...I want to make sure I don't just go replacing parts unnecessarily...thoughts?

    Matt

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  3. #2
    Submariner409's Avatar
    Submariner409 is offline If it won't run, slap in a big stereo
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    Re: 1995 STS hard start and stall problem

    Never hose down a Northstar. Damp rags, brushes, judicious spray cleaners.

    Is the underhood fuse/relay box completely dry inside ?

    Disconnect the TPS and ISC connectors. Check for moisture and blow dry with computer compressed air or Brakleen or Radio Shack electronics cleaner. Do the same for the entire coil pack, ICM, and plug wires. Make certain that the ICM is well grounded.

    Make absolutely certain that the plug wires are connected as shown.

  4. #3
    Ranger's Avatar
    Ranger is offline Cadillac Owners Member
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    Re: 1995 STS hard start and stall problem

    Then take it for a ride and get it up to operating temperature to burn off any moisture.

  5. #4
    Mark C's Avatar
    Mark C is offline Cadillac Owners Connoisseur
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    Re: 1995 STS hard start and stall problem

    I did that to mine last Spring, wasted my ICM. I didn't spray water directly at the coils or ICM but somehow it got in there, car drove about a mile really roughly then stalled and would not restart. Luckily I had a spare one laying around, otherwise I'd have been out a couple of hundred for a new one.

  6. #5
    mdegracia is offline Cadillac Owners Member
    Automobile(s): 1995 STS
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    Re: 1995 STS hard start and stall problem

    First thanks for all the help thus far!

    Okay. I went through an dried everything identified in the post above. Car did start right up. I let it idle for a little while and was able to put it in D and R with no stall. I then noticed the rpm to increase slightly above 1k. I depressed the throttle and it stalled. Then it became difficult to start back up. I noticed it had better chances of starting after the key was turned completely off and then reattempted with a brief pause in between each attempt. It finally started after the 10th try and now its in the driveway idling...scared to test drive it and get stranded. The P026 code keeps coming up...shorted ISC....does this mean the ISC motor is done and needs to be replaced and the car is undriveable til then?

  7. #6
    mdegracia is offline Cadillac Owners Member
    Automobile(s): 1995 STS
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    Re: 1995 STS hard start and stall problem

    Well after letting the car idle for a good 30 mins, it starts up much better, but now the idle just crashes immediately with feathering the throttle. I can feel the throttle depress on its own slightly, but it does seem to correct itself fast enough and then stalls out. On a positive note, I was able to move the car while in idle but no throttle application, on a negative note now I have a bearing on the serpentine belt failing, after I just replaced the idler and tensioner! Son of a B!

  8. #7
    Ranger's Avatar
    Ranger is offline Cadillac Owners Member
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    Re: 1995 STS hard start and stall problem

    Try drying out the ISC motor and connection.

    I just replaced the water pump on my wife's '96 Bonneville 3800. After I finished I took it in to power wash the front of the engine to get all the Dex off the belt. No sooner did I spray it and the tensioner pulley started to screech. Bearing seal looked fine, but I suspect some water must have made it's way in. It had 165K on it so it ddi not owe me a dime. Replacing it was quick, cheap and easy. Nice and quiet after that.

  9. #8
    mdegracia is offline Cadillac Owners Member
    Automobile(s): 1995 STS
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    Re: 1995 STS hard start and stall problem

    Well I ordered a new ISC and TB sensor from Rockauto this AM.

    Any tips on calibrating the new ISC once installed?

  10. #9
    TuneUpsNSuch is offline Cadillac Owners Fanatic
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    Re: 1995 STS hard start and stall problem

    The manual details the idle learn procedure.

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