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Thread: No crank no start help

  1. #1
    Join Date
    May 2014
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    No crank no start help

    I just acquired a 35th SC but I have a no crank no start condition , battery is good, previous owner replaced crank sensor. I can turn over the engine by jumping terminals at starter relay but it still won't start, at the key ignition itself, it doesn't crank the engine over but you can hear the fuel pump prime. What else should I look for? I was hoping that leaving the ignition in the run position and jumping the relay would result in a running car but that didn't happen. Any suggestion would be appreciated

  2. #2
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    See comment #8 in this recent thread:

    http://www.sccoa.com/forums/showthre...69#post1065469

  3. #3
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    Crank sensor wiring could also be messed up. I assume that the previous owner never quite got it running?
    God bless!!!

    1990 SC auto ... red outside, gray cloth inside ... ~205,000 miles (and climbing) ... driven daily!

  4. #4
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    KMT I'll check out the ignition switch and report back. Mazza, yes the previous owner could never get it running again, he replaced the crank sensor and I guess that didn't help, I checked out the the connector for the sensor and it was fine, the wires were in good shape. I checked out a schematic and it listed a "starter interrupt relay" and a "anti theft module" , does anyone know where either is located and could they also be the problem. One last thing, I did scan it for any codes in the KOEO position and it came out a 11 which I found to be system passed. I appreciate the help as I really want to get this car going as I have never seen another 35th SC here in Hawaii

  5. #5
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    Try this for 'no start' help:

    http://mnharms.com/tutorials/disnostart/

  6. #6
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    Quote Originally Posted by Redkoa5 View Post
    KMT I'll check out the ignition switch and report back. Mazza, yes the previous owner could never get it running again, he replaced the crank sensor and I guess that didn't help, I checked out the the connector for the sensor and it was fine, the wires were in good shape. I checked out a schematic and it listed a "starter interrupt relay" and a "anti theft module" , does anyone know where either is located and could they also be the problem. One last thing, I did scan it for any codes in the KOEO position and it came out a 11 which I found to be system passed. I appreciate the help as I really want to get this car going as I have never seen another 35th SC here in Hawaii
    The starter interrupt relay will prevent the car from cranking at all. So that's not the trouble.

    A complete lack of spark is usually either related to a problem with the main power wiring to important components like the EEC, or to a failure in the primary side of the ignition system.

    A faulty crank sensor will prevent it from working. You can test that with a 12V LED test lamp. (Must be 12V to make sure the signal is high enough.)

    An open circuit in the EEC ground could also allow crank but prevent start ... but then the computer would not give any codes. So I don't think it's that.

    I would look at the ignition switch, and then if nothing turns up, look at the ignition trigger system.
    God bless!!!

    1990 SC auto ... red outside, gray cloth inside ... ~205,000 miles (and climbing) ... driven daily!

  7. #7
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    May 2014
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    Replaced ignition switch and still no start, also cleaned ground terminals at battery. From the red/lt blu wire at the ign. Switch to the starter relay there is no cranking voltage, but at the switch itself there is, according to my schematic, there must be a fault between the ign. Switch and the starter relay. I checked to see if I could check spark at the coil by jumping the terminals at the starter relay and using a spark tester between the coil and spark plug wires, I actually have spark to each cylinder, I also have 40psi of fuel pressure when the key is turned to the on position, so I have spark and fuel but still no start. It does sound like it really wants to run when I do jump the terminals at the starter relay, could it just be some worn down spark plugs?

  8. #8
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    I've read that changing plugs is a pain but I'm all for it to get it running. The schematic I'm looking at shows the red/lt blue wire at the ign. switch which I do have cranking voltage shows that it goes to the starter interrupt relay to the ECM, to the neutral switch then to the starter relay, so I'm assume the fault is somewhere between there which is causing the no crank condition. I failed to mention that while cranking the engine over at the starter relay, the up shift arrow does turn off.

  9. #9
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    Ok, I am sorry. I thought I read that the car cranks, but does not start. I see now that it does not crank at all.

    Then the starter interrupt relay is not ruled out. It's testable, though. Back to that in a bit...

    When you turned over the car by jumping the starter relay, did you have the ignition key to ON? If so, it should start and run.

    (Anecdote: Last year, I replaced my starter relay mistakenly for a similar condition. Even tested the interrupt relay. Turned out to be the ignition switch.)

    Spark plugs would not prevent the car from cranking.
    God bless!!!

    1990 SC auto ... red outside, gray cloth inside ... ~205,000 miles (and climbing) ... driven daily!

  10. #10
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    S Mazza thanks for the help, the ignition switch is in the on position when I'm jumping terminals at the starter relay but it still doesn't start. the ignition switch is new(replaced it yesterday as I found it seperating), but jumping the starter relay only cranks the engine over. I'm gonna go ahead and replace the starter relay since it's a cheap part. Where would the starter interrupt relay be located? The schematic shows cranking voltage goes from the switch, to the starter interrupt relay, the ECM, the neutral switch then finally to the starter relay, I'm gonna check voltage at all those locations but at a loss as to where the interrupt relay is located. Would badly worn spark plugs prevent the car from starting

  11. #11
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    Does your car require the brake pedal to be pressed when starting?

  12. #12
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    Btw what I meant about the spark plug question is not that it prevents it from cranking over but could it be so worn that the fuel is actually flooding it out? There's a smell of fuel through the exhaust when I jump the relay and it's cranking over, and it also sounds as if it wants to start and fire up when I jump the relay, but it just doesn't

  13. #13
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    Note that if you depress the gas pedal to full open when cranking that the injectors are shut down. Might be a way to clear inordinate flooding, which is not that easy to do, I think, but...

  14. #14
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    I did step on the brake when I tried to start it yesterday but it still doesn't crank over, i was on the brake also because I tried to see if it would start in both park and neutral position but no difference

  15. #15
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    Still might help to debug that circuit too.

    Did you run thru the no start procedure linked above yet?

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