PT CRANKS, WON'T START

  • Tiny
  • JohnK59
  • 2003 Chrysler PT Cruiser
  • 201,000 miles

The camshaft position sensor was replaced @ 201,000. 2 weeks later, the car stalled in traffic and would not restart. No DTCs presented. There was no spark at the #1 plug, the tube was half full with oil. Replaced valve cover gasket, tube seals, plugs and wires. No spark.
Broke crankshaft position sensor receptacle while removing connector, replaced sensor. Still no spark, no codes. Tested starter due to never having heard car start, and was not impressed by sound of cranking. Starter and battery both checked sat.
No +12vdc @ coil with key on. Jumpered ASD relay, and saw +12vdc @ coil center pin. No start. Swapped horn relay (known good0 no start, no +12vdc. Fuel pump runs, pressure @ fuel rail. Voltage drop @ starter w/in limits. Replaced PCM w/ known good, no start, same conditions, no codes.
Timing belt is intact, pistons cycle with starter. If the presumed original timing belt (owner has never replaced belt since 75K), had jumped timing, I would expect to see an out of sync code> Nope
I've gone to alldata, as Haynes manual has no engine control info.I have schematics, have exhausted all troubleshooting ideas. Could the flywheel be worn to the point it is not spinning the engine fast enough, and setting an ASD shutdown command?
What parameters, exactly, cause the ASD relay to shut off? The owner really likes the car, which is in surprisingly good condition, and really can't afford to replace it now. All help would be greatly appreciated.

Thanks

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Friday, August 26th, 2011 AT 10:55 PM

24 Replies

  • Tiny
  • KHLow2008
  • Expert
  • 41,994 posts

You did not mention anything about the Crank Position Sensor and from symptom description, that should be the component you should concentrate on to get the ignition coil signal. Btw was the ignition coil tested or substituted?

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Sunday, August 28th, 2011 AT 8:12 AM
  • Tiny
  • JohnK59
  • Member

Since there is no B+ at the coil, I have not considered the coil as a possible problem/solution. Both cam and crank sensors are new.

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Sunday, August 28th, 2011 AT 1:13 PM
  • Tiny
  • KHLow2008
  • Expert
  • 41,994 posts

Did you check the ASD relay grounding circuit at the PCM?

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Sunday, August 28th, 2011 AT 1:22 PM
  • Tiny
  • JohnK59
  • Member

I am pretty much clueless as to the purpose or operation of the ASD relay circuit. It looks like the PCM sends a ground signal to collapse the coil, but I don't understand the grounding circuit itself. I assume the ground circuit for the injectors is working, as there is fuel in the intake runners.

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Sunday, August 28th, 2011 AT 2:20 PM
  • Tiny
  • KHLow2008
  • Expert
  • 41,994 posts

When the PCM is powered by the ignition switch, it would ground the ASD relay via connector C3 terminal # 2 (Dark Blue/Yellow wire). Check for continuity between the PCM and ASD relay for the wire.

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Sunday, August 28th, 2011 AT 5:08 PM
  • Tiny
  • JohnK59
  • Member

C3-2 is unpopulated. Alldata shows ASD relay control leaving the PCM on C3-3, via a DKBLU/YEL wire which rings to E2 and E4 on the ASD socket. All the terminals on C3 for the ASD relay ring to the sockets they're supposed to on the relay socket.

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Sunday, August 28th, 2011 AT 7:56 PM
  • Tiny
  • KHLow2008
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Sorry for the typo, it should be C3 # 3. Do you have continuity between the PCM and ASD relay ( E2 of relay to C3 #3 of PCM)?

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Sunday, August 28th, 2011 AT 8:10 PM
  • Tiny
  • JohnK59
  • Member

Everything I've checked has continuity from the PCM. C3 rings to E2 and E4 of the ASD relay socket, which I assume is the coil. The drawing on Alldata is a little confusing, as the coil resembles a resistor.

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Sunday, August 28th, 2011 AT 8:26 PM
  • Tiny
  • JohnK59
  • Member

What I don't understand is, I jumpered the 30 and 87 sockets on the relay socket ( I'm not sure what E points this corresponds to)and got B+ at the coil and injectors and still no spark at the plugs. What conditions cause the ASD to turn off?

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Sunday, August 28th, 2011 AT 8:39 PM
  • Tiny
  • KHLow2008
  • Expert
  • 41,994 posts

That means the PCM is not grounding the circuit for the ASD relay.
You mentioned substituting with a known good PCM, maybe you should retry again.

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Sunday, August 28th, 2011 AT 8:48 PM

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