Rev counter not working since moving to fuel injection

[Midlifecrisis2001]

An odd one this or maybe it's quite commonplace. I have 1989 super seven that previously run a crossflow that has now been upgraded to a fuel injected Zetec, however although the engine runs (very) well the tacho no longer works! The ECU supplier M Tech Automotive tell me it's because I'm running an old 12v tacho and the ECU is configured for a 5v one - does that make sense to anyone here?

 

All thoughts most welcome :)

 

thanks

Clive

[Jonathan Kay]

It makes sense, but did the ECU supplier offer any solutions?

 

Jonathan

[Midlifecrisis2001]

Yes something to do with putting some diodes in... Just wondering is anyone else has done this?

[garybee]

I take it that you are definitely getting the tacho' feed from the ECU and not from the coil pack/EDIS unit?

[Rob Walker]

Probably more to do with the fact that you are now running a coil pack and not the single coil/dizzy. The coil pack requires two inputs and +12v from your ecu. The tacho will now have to be driven directly from the ecu pin 12 on an emerald and not off the coil.

 

You cant have it easy all the time.

 

Rob

[Midlifecrisis2001]

I didn't explain that very well. The engine was upgraded to a carb' Zetec fifteen years ago along with a coil pack. The recent change was moving from Weber carbs to Jenvey's. Also the ECU isn't an Emerald it's actually an M Tech badged device.