89 Tach with EEC V Strange Readings

Ok her we go again with another off the wall item.

89 Bronco 2 with a 97 5.0 engine.
EEC V system.
Hooked up the OEM Tach (89) to the EEC V tach wire, and reads great at idle (750).
Increase RPM and 1500 reads 4000 and never goes above 4k on up.

I know they are from different worlds but why does it do this?

Ideas?


[img]/forums/images/smiles/icon_confused.gif[/img]

wut engine was in the bronco before V6 ?

Not sure
Here is the back of the Tach.
Someone said you could jumper 2 pins to get it close.
But which?
http://ratstangrestoration.com/89Tach.jpg
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Ok people here is a tech tip.
Or Tach tip if ya like.
Dont waste your time modding your tach.
Go to the wrecking yard and pull a tach from a fullsize Bronco w V8.
Swap the electronics and faceplate and put er back in.
Works great and no errors to play with.
Total cost:
10 Bucks and 2 hours.
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