QuestionI have a 99 plymouth grand voyager that the fuel pump keeps turning on and off. When you put your key into the ingnition and turn it on enough to get power you can hear the fuel pump "whirl" like it is supposed to then it does it again and then again. You also hear the fuel pump relay going nuts. I have replaced the relay and the fuel pump.
Last nigt I removed the relay heard more noise and it was coming from the egr solinoid I removed that. Everytime the fuel pump cycles the service engine lights come on then goes off etc..
After removing the egr solinoid you hear a high pitched electrical squeal coming from the PCM then it goes away and the service light comes on then the squeal comes back and the light goes off. I am thinking it is the PCM but I thought I would get your opinion.
The van does start and run until the fuel pumps shuts off then it starts to die then the fuel pump kicks in and then it revs back up.
Help I am lost!
Thanks!
AnswerHi Chris,
I certainly suspect that the PCM is flakey. But I would first check two voltage supply sources to it:
There is supposed to be a constant 12V from fuse #16 (20 amp) in the power distribution center under the hood (at least that was the fuse used in '98 according to my Haynes van manual), so check to make sure that fuse doesn't have a subtle crack such that it opens and closes by itself. Measure the downstream side of the fuse for whether it shows a constant 12v.
The other source is from the ignition switch (dark blue wire at the switch): you could look at voltage on that wire and verify that it is constant when you have the ignition switch in the run position. A flakey contact in the switch could do the same thing.
I offer those possibilities because it behaves like it is being turned on and off, like if you were playing with the ignition switch.
If those voltages seem solid, then consider getting a new PCM.
Roland
