no tach

**CHRISFORMULA** · 08-24-2010, 05:53 PM

hey guys i was on here with the same question a week ago but no real help came of it. i have no tach. the whole cluster works but no tach. engine runs great no codes so the problem must be betwwen the cluster and the pcm. check white wire it has 5ish volts and the pcm but only 0.9 ish at the cluster it self. 0 resistance from pcm to cluster. I need some help some one with a wire diagram or any ideas thanks.

chris

**Cutlass** · 08-24-2010, 06:53 PM

98 tach wiring

**CHRISFORMULA** · 08-25-2010, 04:11 AM

thanks i'll check it out

**Frost** · 08-25-2010, 05:06 AM

You don't have any cam sensor codes do you? The PCM uses the CPS for RPM signal but it drives the dash tach based on feedback from the cam position sensor. Whenever there is an issue there, you can lose tach. If it's cam sensor wiring, you will occasionally get a 'fart' when starting the car or notice that it doesn't start quite as easy as it 'should'.

**CHRISFORMULA** · 08-25-2010, 05:15 AM

this car start and runs great. i ran last week against my freinds z06 cause the car ran good and it did ,door to door through ever gear so ya its running and starting good. only thing is i am going by ear for the shifts. could the car run with the cam signal off or not there at all? also i have a 255 in line pump that used to prime then stop if you don't start the car-- just like a reg fuel pump right. but ever since this issue the pump runs fine just never auto stops with the key on and not started the pump now runs on and on now.

**Frost** · 08-25-2010, 09:01 AM

Yes, the car runs without the cam sensor, it just makes the cars act goofy at startup and you lose the tach signal when they have an issue.

**CHRISFORMULA** · 08-25-2010, 09:05 AM

really wow and it would still run that good. it has no check engine light either is that possible as well. where is the sensor must be at the back can i see a pic if possible.