Having issue with power supply regarding wire running from the crankshaft
sensor. When problem happens, the van will crank but not start. On a scope,
when it happens it does not show any codes, but indicates crank 0, cam 0.
The crankshaft sensor was replaced 3 weeks ago after the problem first
started (with a non-Chrysler product). The mechanic at that time still had
the issue of the no-start after this was done. The mechanic advised that the
wire regarding the crank sensor (when the wire was disconnected from a power
source) seemed to be drawing power from another wire in the harness. He
placed the wire on the opposite side of the wire harness, and it started
fine for 3 weeks. Recently, the van stopped again, and this time there also
seemed to be a power issue with the wire connected to the crankshaft sensor.
The same mechanic said he was testing the wire, and he unplugged the wire
(one near exhaust manifold and another near front of engine) and it started
again and has been fine. He says I have to do something, and I am wondering
if that wire may be corroded, and should be replaced. The mechanic is
talking of replacing the wire with another length, and soldering it to the
original wire below the plug-in. Does this seem a reasonable solution. He
says it may in fact be something else. What are your thoughts on this
matter. Thanks for your help.
Running -TO- the crankshaft sensor.
8 volt supply, pin 44 of the PCM, supplies 8 volts to the crankshaft
sensor, camshaft sensor and flex fuel sensor if equipped.
Any of these can short out and kill the supply voltage to the other
sensors making them inop.
On a scan tool?
I'd unplug all sensors powered by the 8 volt supply and test for 8 volts
being present. If so, one of those sensors may be shorting and drawing
the 8 volt supply down.
If you don't have 8 volts at the sensors when they are unplugged, look
for an open circuit in the 8 volt supply wire, if you don't find an open
circuit, test for 8 volts directly at pin #44 at the PCM.
Also check for a broken flywheel, if the cam and crank sensors go out of
synch because of a broken (shifted) flywheel, you'll get the exact
symptoms you describe.
Thanks for your help. I would point out that we also replaced the computer
in the van 3 weeks ago, with a used one. I will mention your comments to my
mechanic. He worked at Chrysler, and was mentioning to me a situation about
a van that he worked on while at Chrysler, that had some type of flywheel
problem, that induced other problems, like you were referring to. Please
note that we weren't using the van a lot over the winter, and it was sitting
for approximately 2 months. When I started it after sitting for 2 months, it
would not move, and I waited for approximately 5 minutes before it would
move. I remember hearing a "clunk" noise just before it started to move.
Would this be a symptom of a flywheel problem? He is going to look at it
again next Thursday. Mike
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