Edmunds Answers

Answers

  • docj 03/11/09 12:02 am PST

    Check the timing belt.

    The 3.5 L timing belt drives the water pump and these are great for the pumps going out and taking out the belt.Even if the pump is ok,still the timing belt could be bad.
    If thats the case,always replace the water pump and timing belt together.

    If the camshafts arent turning,the cam sensor will not send a signal to the PCM to fire the coils and the Automatic Shutdown Relay (ASR )will shut down the Coil,Injectors,alternator,fuel pump relay,heated 02 sensors within like 1-2 seconds of cranking.

    Take a couple bolts out of the front cover on one side,loosen enough of the rest to slightly pull the cover open at the top and have someone crank it while you look in to see if the cams are turning.You can peek in there too and can see if the belt is shredded.

    Let me Know

    Doc J

  • zaken1 03/11/09 1:33 am PST

    The engine control system in this vintage of Mopars was a bad design. The way it was set up, if any sensor which ran off the computer's 5 volt power supply developed a short; it would shut the whole engine down. They redesigned the system in 1977 and later models to be immune to this problem; but it still leaves all the earlier cars vulnerable to sudden, total shutdown.

    The sensors which can cause this problem include the throttle position sensor, air charge temperature sensor, MAP sensor, and the heating elements in the oxygen sensors. The heating elements in oxygen sensors are one of the most common items that fail by developing a short.

    If you can have all these sensors tested by a friendly parts store (or at least some of them tested) the problem can be greatly simplified.

    Incidentally, with reference to the first person's answer; you can easily check for a broken timing chain by running a compression check on the engine. If the compression comes out within manufacturer's specifications, the timing chain has not slipped or jumped out of sync.

  • zaken1 03/12/09 12:41 am PST

    Just wanted to add that you don't need to pull each sensor out to have it tested. Instead, you can just disconnect each of the sensors (singly or in combination). That would compromise the engine's running quality if it started; but if you disconnect a sensor which is shorted, the engine will then have sparks and at least become able to start. So that would be a quick and easy method of identifying which (if any) sensor is shorted.

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