Hi there. Got the mk2 agu back on road recently after 9 ish years and the rev counter no longer works. I sometimes see a flicker of the needle on startup. I’ve tried a set of mk3 ce2 clocks and Is the same. I installed a tachfix adaptor 10+ years ago and last I remember when it was last on road it was all good. I’ve checked all wiring and no issues, as soldered and heat shrunk etc. I assume the adaptor has failed, can I prove a signal input without an oscilloscope? Will a volt meter show anything? The car runs fine so assuming if crank sensor was duff it wouldn’t run, as I’m guessing that’s where the signal comes from? Can these adaptors fail? Thanks for any input
You'll have to measure with a scope, a Voltmeter is way too slow for the signal. I can send you an amplifier when needed
mk3 clocks work directly from the output of the ecu, did you feed the ecu signal straight to cluster bypassing the tach adaptor? will tell you ecu signal is ok at least. output from tach adaptor should be a 12v earth spike, its pretty high amp as originally it would have been triggered by the tci module to coil earth pulse
Ah right. No I didn’t bypass the adaptor I just plugged the clocks in, as same ce2 single plug and assumed the rev input signal side of things was the same. Ok I may just link the wires out and plug the clocks in again and prove signal is all good. Cheers
Well just to confirm that Danpy’s signal adaptor has done the trick. The old extraefi.co.uk one from years ago had failed. Upon disassembly I can see corrosion on a resistor inside and bits around it. Dan has supplied a new working one for a good price inc postage for anyone else in the need
