Early tach stopped tach-ing

914efi · 01-02-2010, 06:43 AM

Should I did into it, or just replace? Needle still moves, but very lazy and low for what the engine is doing.

JivenJim · 01-03-2010, 10:33 PM

Clean your connections to TACH with sandpaper or file. Check you Ground stud connections up high over shift pedel has been cleaned. Follow all the brown wires up to that Christmas tress stud. Clean.

If no joy. You can replace it with any Pre 85.5 844 or a 87-88 924S (my choice)

Sometimes spraying WD-40 in the Speed cable (plugs in to Tach) gives this mechanical cable, cleaner rotation and signals.

914efi · 01-04-2010, 07:19 AM

Thanks. I just put this car together, so I cleaned all of the grounds when the dash was out. MPG needle is working fine, so I think the speedo signal is OK. I'll root around and see what I can find. Maybe an opportunity to do something fun with the tach.

ERAU944 · ERAU944's Garage

if you end up deciding to replace the tach i've got one or three laying around...

Mike

exitwound · exitwound's Garage

I have the same issue on a late dash. MPG works fine but tach is intermittant. Will kick itself on eventually.

Stutzdriver · Stutzdriver's Garage

Make sure you replace it with the correct tach, there is a difference in the early tachs (ask me how I know?). If you have the upshift light you have to replace it with the same as the circuitry in the upshift light tach is different and the other cluster will peg the guages if you use an earlier tach.

I found mine to be a bad tach and bought a correct replacement for less than the estimated repair cost. Now it works perfectly!

I have an early (non-upshift light), perfectly working tach is you need it.