2005 Chrysler PT Cruiser

Tiny
LGUNDERWOOD
  • MEMBER
  • 2005 CHRYSLER PT CRUISER
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 13,500 MILES
I change the cam and crank sensor which the code said was out. And my car still wont start. Its not dead it just wont start. Could it be my fuel pump.
Wednesday, March 3rd, 2010 AT 10:57 AM

3 Replies

Tiny
CARADIODOC
  • MECHANIC
  • 33,867 POSTS
It's not likely both sensors failed at the same time. Did you get codes for both of them? Did you check for spark?

Back probe the dark green / orange stripe wire at the coil pack. There must be 12 volts on that wire for one to two seconds when the ignition switch is turned on, then it will go to 0 volts. That is proof the circuitry is ok.

Next, the voltage should come back during engine cranking. If it does not, there will be no spark and the fuel pump won't be running either. Normally the first suspect would be the camshaft position sensor. The crankshaft position sensor would be next. Since you replaced them already, we'll move on.

Next, check the timing belt for a jumped tooth. If it jumped one tooth, the Check Engine light would have turned on. At two teeth, the engine computer stops the engine. At three teeth, open valves hit the pistons. If the belt timing appears to be correct, tie the belt to the camshaft sprocket with a piece of wire, then remove the sprocket from the camshaft. Inspect the dowel pin between the cam and sprocket. Replace it if it is sheared off. The sprocket can turn just a little. The timing marks will be perfectly lined up yet, but the camshaft is late by a few degrees. Since the camshaft position sensor is on the other end, its signal is out-of-sync with the crankshaft position sensor's signal so the computer turns the Automatic Shutdown (ASD) relay off. That relay is what turns the 12 volts on to the ignition coil pack, injectors, fuel pump or pump relay, alternator field, and oxygen sensor heaters.

Caradiodoc
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Wednesday, March 3rd, 2010 AT 1:45 PM
Tiny
LGUNDERWOOD
  • MEMBER
  • 1 POST
Thanks for the info, I will try that next. Would you send me a diagram of where it is located. And any information to take it off. This will be my first time working on a PT.

Thanks again.
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Thursday, March 4th, 2010 AT 8:13 AM
Tiny
CARADIODOC
  • MECHANIC
  • 33,867 POSTS
Which engine do you have? This doesn't apply to dual overhead cam and diesel engines. The camshaft dowel pin was a common problem on Neons, but only on the single cam engines.

Before you start tearing things apart, we need to figure out if the pin is a likely suspect. In the meantime, since you had codes for both sensors, check for voltage on the orange wire on either sensor. There must be 5 volts with the ignition switch turned on. If that is missing, unplug the cam and crank sensors, then measure again on one of the connectors. You must cycle the ignition switch off, then back on. If the voltage comes back, one of the sensors is shorted. When one of them shorts the 5 volt power supply, the engine computer shuts the supply down to protect it. The supply will not be turned on until after the ignition switch is cycled off and back on. Plug one sensor in at a time while monitoring the voltage. If it disappears when one is plugged in, that one is shorted.

Caradiodoc
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Thursday, March 4th, 2010 AT 6:41 PM

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