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need help rpm guage quit on me

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Old 09-09-2009 | 09:18 AM
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Default need help rpm guage quit on me

the previous owner installed a raptor shift light on the car im thinking that where he tapped into the pcm might have came loose.. can anyone think of another reason on why the rpm guage would stop working?
Old 09-09-2009 | 10:56 AM
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i have to have this fixed before going on the dyno
Old 09-09-2009 | 11:10 AM
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that's kinda hard to say without seeing the wiring. Can you trace the shift light wiring and see where it goes? Different people tap in to different places so it's hard to say where to check. I'm guessing he tapped in near the PCM ('cos it's a '02) so check there first. When you find it disconnect it and see if the tach. works. If it's not that, you're gonna have to go looking and it's a PITA 'cos it uses a serial data line and that line is spliced on to every control unit and any one of them may be causing the issue. Any other gauges not working/warning lights illuminated? Reason being, that I recently diagnosed/fixed a car that had the Tach/fuel/ABS lights issue and traced it to the EBCM that had an internal short and was back-feeding the serial data line slice pack, so anything connected to that node was going crazy!
Old 09-09-2009 | 12:22 PM
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no all other guages work properly every now and then my trac control goes off when i didnt push the button but thats no big deal to me an yes i can see where he spliced into the pcm.. so i should disconnect that and see if the tach works and if it doesnt thats my problem? im sorry when it comes to wiring im a dumbass never messed with wiring before
Old 09-09-2009 | 08:22 PM
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has anyone else had this happen to them if so how did u solve the problem
Old 09-09-2009 | 08:58 PM
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You throwing any SES lights? I think (don't quote me) but I think 02's run the tach off readings from the cam sensor. If your cam pos. sensor died, so will the tach.

It's been a while since I've chased down electrical bugs or went over a schematic on these cars.
Old 09-09-2009 | 09:40 PM
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Anyone have pics of the splice pack?
Old 09-09-2009 | 09:53 PM
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Originally Posted by Damian
You throwing any SES lights? I think (don't quote me) but I think 02's run the tach off readings from the cam sensor. If your cam pos. sensor died, so will the tach.

It's been a while since I've chased down electrical bugs or went over a schematic on these cars.
Yep CPS runs the tach but I would think you would be throwing a code so......what the hell do I know.......I am sure someone more knowledgable will post up or go to internal and you will for sure get an answer.....
Old 09-10-2009 | 12:22 AM
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the rpm guage used to not work when i would start the car but would start to work about a min after it was started ... then just quit working all together yall think that could be the cps? or something shorted out?
Old 09-10-2009 | 09:20 AM
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It could just be the motor inside the cluster too. I've seen that happen. Got another 01-02 TA near by you could swap clusters with real quick? That will eliminate that option. If the CPS is bad you should be throwing a light.
Old 09-10-2009 | 10:52 AM
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car was a throwing a o2 code before so if it was i dont know.. right now i got the heads and intake off due to a collapsed lifter so i will go ahead and replace the cps since it can get to it very easily and hope thats the problem
Old 09-10-2009 | 10:53 AM
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If you ever have a pop or backfire during starting (or it doesn't crank right up like it used to) then it's the cam sensor. I would still suspect the cam sensor or it's wiring before suspecting the dash gauges, but stranger things have happened.
Old 09-10-2009 | 05:12 PM
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Originally Posted by Frost
If you ever have a pop or backfire during starting (or it doesn't crank right up like it used to) then it's the cam sensor. I would still suspect the cam sensor or it's wiring before suspecting the dash gauges, but stranger things have happened.
im replacing the sensor before i bring it to you to dyno this month
Old 09-10-2009 | 09:06 PM
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Don't change (or even remove) the CPS if you don't really have to, that will not cause this problem anyway. Usually the cam sensor will set a code if it's the issue. Not always, but it usually comes up pretty quickly. So does it pop or backfire or seem slow to start?
Old 09-10-2009 | 09:28 PM
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its slow to start.. i already got the sensor so im going to replace it saturday and put the top end back on the car and see if that was the problem



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