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rpm hand not moving

94grandprix

94grandprix

New member
ok i searched and couldnt find anything and wasnt for sure were to post this at but when i turn m 00 pontiac gp gtp switch over as normal my rpm hand and speed hand jumps as normal and like the others,but when i crank it,it dosent move,what could it be?
 


You've left out some vital information.

Does the car start?
If it does start, does the gauge deflect to expected rpm?
 
yes the car runs,drives everything and no it dosent move when started but jumps when you turn the switch to on like all the other hands do
 
If it passes the test procedure with key on then I would think that the signal is not getting to PCM from the crank sensor. The stepper motor is obviously working. This is kind of confusing because the car theoretically should not run.

Maybe someone else has an idea.
 
I'm sitting back waiting to see if the needle moves with rpm. You said it doesn't move when the car is cranking.. nothing about once it's started.

Can you clarify please.
 


Ok.. and next question. Your user name says 94 GP, do you actually drive a 94?

You gave us very little info dude.
 
i did and when i first posted i put when i turn my 00 pontiac gp gtp switch over as normal all the hands/needles move/jump as normal but when the car is started/running the rpm needle dosent move,im not sure what else to say
 
Bill

If there's four wires that go into the CKP then I would suspect that there are two output waveforms?...One for the PCM and one for the cluster?

EDITED: Maybe one for PCM and one that goes to the ICM.
 


ehhhh damn laptop screen at work. it was off the screen and I figured there wasn't anything valuable there.. sorry man.

Ok.. hmmm can you scan the car for rpm? If so..that'll tell you if you are getting rpm to the pcm which would mean a bad connection somewhere from there to the cluster. If not, just swap your crank sensor and hope for the best.
 
So he should test continuity from the white wire to the cluster?

ECMTachSignalWire.png
 


So then it can't be the CKP. Maybe there's no signal from the ICM out to the cluster.
I never thought the ICM could be the source of this problem. Never had to think about it though.
 
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