Tachometer, where to look for problems?

[unclemikeys2001]

My RPM tach sometimes works & sometimes doesnt, its 50/50. Just cuts out when it feels like it & will kick back in anytime it feels. All other gauges work perfect. Im trying to fix this & realize it may be a connection. Is there anywhere to look 1st before tearing out the gauge cluster? Also I hear alot of bad stuff about the VDO gauges. Are they really that bad? And could my problem possibly be a bad guage?

[Razorback1980]

You may try this before replacing anything. I don't know how frequently this is the problem though.

http://www.pelicanparts.com/techarticles/944_taillight/944_gauge_problems.htm

[unclemikeys2001]

Thanks for the link. I guess this would be the 1st thing to do. Clean my contacts. Doesnt seem removing the cluster is that bad. Any other added tips for removing this before I attempt it?

[livewirevoodoo]

Juve did that write-up, so you are in good hands.

An interesting read, specifically:

4. Now, look at the back of the panel – on each side, where the combo gauges live, you see 2 black football (or rugby ball if you are in the UK) shaped objects with a brass nut in the center. Loosen these with the socket. After you have gotten the nut and washer off, lift the football shaped thing off of the circuit board. – these are the main electrical connects for the combo gauges.

5. Clean the nut, washer, and the brass posts, as well as the threaded post sticking out of the circuit board with metal polish – then wipe down with alcohol to remove any residue.

I was not aware of those football shaped dealies. The only thing I have cleaned in the past were the cable attachment points. I learned something new today.

As your sig mentions a early-model 944, this walk thru might be a bit more applicable for cluster removal (deals will removal of speedometer cable):

http://clarks-garage.com/shop-manual/elect-06.htm

[Granite 944]

Also check the green wire connections in the 9 pin connector in front of the firewall. Also could be a bad green wire connection at the DME connector. #1 pin, IIRC. I've had both happen to me. Connectors behind the tach, yep.

Are these VDO gauges bad? I don't think so. Age, and PO's do horrible things to any car, no matter what gauges you have. Butt, the gauge could still be a bad one. Eliminate everything else first.

[Razorback1980]

Thanks livewirevoodoo, I totally missed the fact he had an early model. I know about the late ones, but I am unsure whether the early ones had the same type connectors on the back of the instruments. Look closer at the other two suggestions than mine.

[MURF]

we replace early tachs pretty regularly..later ones usually are fixable