270 Killer Wasps!

[gjkrv8]

I had the same problem and looked at the signal from my LS1 ECU with an Oscilloscope and found it to be a 1 volt peak to peak square wave. I told Howards and they modified my VDO Tacho to suit. Tried the resistor pull up methed and that didnt seem to work.

Not sure about the later ECUs.

Rgds

Gregg

[Doubledip]

the 1K / 3K trick works on the later model ECU's (LS1,E38,E40)

make sure you have one end of the resistor onto ignition the other onto the tacho wire...

the 4CYL bit is only if the tacho output has not been adjusted in the ECU, but will make no difference if the tacho is not registering at all..

you can get the tacho modified to work but is rather costly compared to buying a 10cent resistor and fitting yourself.

[stumpeater]

I put the 3 K ohm resistor as suggested, and tacho is now working, certainly worth a try Paul, on your VDO.