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Registered User
Join Date: Jul 2016
Location: Norway
Posts: 12
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Tachometer in 1978 930 not working anymore
Hi
I have a 1978 930 were the tachometer suddenly stopped working. Boost gauge still working, but tachometer shows 0 all the time. I am not sure were the wire for the tachometer goes, so if anyone have a wire diagram it would be good  I guess I have to check the tachometer it self, and also the wire/signal. Is the signal going thru the ignition box? I have now a MSD ignition, and have seen that people having trouble with signal after installation, but this box has been in the car for 2 years now. I would be very thankful if someone could give me some tip to fix this Have also read something about a bad alternator could give this fault? Only problem i can se so fare is the tachometer. Everything else works perfect. Sorry for the bad english, but hopefully you will understand what i mean Best Regards Tor Erik |
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07-11-2016, 07:08 AM
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Registered
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A bad alternator can kill the tach. But usually you get a warning - the tach starts bouncing around - voltage spikes from regulator in bad alternator. You can check alternator with voltage measure at battery while engine running thru to say 2500 rpm.
The tach runs off the bk/vi wire - which feeds into the TD terminal on back of tach. This wire comes direct from CDI . So direct from CDI (thru 14 pin connector on relay panel) to TD on tach. Make sure you have 12 v at tach also. And an earth. If you loose either, tach no go also. Alan
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83 SC, 82 930 (track) - Stock except for RarlyL8 race headers, RarlyL8 Zork, K27-7006, 22/28 T bars, 007 Fuel head, short 3&4 gears, NGK AFR, Greddy EBC (on the slippery slope), Wevo engine mounts, ERP rear camber adjust and mono balls, Tarret front monoball camber adjust, Elgin cams, 38mm ported heads, 964 IC. 380rwhp @ 0.8bar Apart from above, bone stock:-) |
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07-17-2016, 06:46 PM
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