[retirednak]

I just did the Z28 cluster install on my '96 and I'm having tachometer malfunction. I ran the wire to red 13 on the pcm and made sure it snapped in. It seems to me that the tach is not receiving the signal from the pcm. Can somebody give me an idea where to start? Is there a way to check to see if the pcm in fact is sending power to the tach or I might have a break down in the wire? Is there any other way to hook the tach up? If our cars had the standard HEI distributor,it would be a done deal,but with the optispark,I'm lost. I don't think having my pcm tuned by Brian at pcmforless would cause my tach not to work.

Help me out here guys,
Casey

 

[cletus284]

ooh, I remember something about the '96's sending a 4 cyl tach signal. Maybe that's it. sorry I can't help you more.

 

[94MI9C1]

I think after reading this somewhere that the Tach itself in the Impalas use a 4 cylinder signal or decode the 8 cylinder to a 4, I have done a cluster swap to a 96 with no issues, not sure what would cause this problem though.

 

[pcordes1979]

The 4 cylinder tachometer issues is only with the 96 Impala SS's. The 96 Caprice's PCM tach output is a standard 8 cylinder output. If the issue was dues to that the tachometer would read double of the actual speed. I would double check to make sure you ran the wire to the correct position. It could also be a problem with the cluster itself. - Peter

 

[retirednak]

I've tripled checked to make sure the wire snapped into the pcm plug.

Can somebody confirm that the wire goes to Red plug #13?

Can somebody tell me how to test the tach wire to confirm the pcm is sending a signal?

 

[94MI9C1]

Red or "A" 13 is correct, I would think with a digital multimeter with the car running, check the wire on the volts scale you should see a variance in voltage i.e. a rise with the RPM rise in the motor.

 

[retirednak]

Just talked with a buddy who has a multimeter with a tach reading on it. Will give it a try. I'll update when I find out more.

Thank you for all the help
Casey

 

[Choo]

I just hooked up a autometer tach in my 95 ss and it's not reading the rpm. I'm getting the rpm reading from the #13 pin on the red connector. Anyway I can test the output from the #13 pin?

 

[Choo]

Problem fixed, the connector was not pushed in all the way in the red plug..oops