Pinto With 1600Gt Rev Counter Wrong Revs

[dandanfireman]

Hi guys any ideas how to lower the revs on a standard pulse tacho thats from a 1600 crossflow to that of a 2000 ohc pinto? Any help would be appreciated.

 

Thanks

 

Dan

[cb750]

Shouldn't it read the same as both are 4 cylinder engines?

[Longboarder]

Tell us about the ignition system currently in use.

 

Nigel

[Bob Tucker]

Any idea how much it is over reading?

[Jez Morton]

You may need the inline capacitor thingy the sierra would have had fitted to clean the signal. Black box with two wires coming off it around 20x30mm if i remember correctly. A friends tacho was reading wrong nearly double i think until I fitted the capacitor/suppressor thingy.

[dandanfireman]

Its an efi pinto running a standard ford motorparts electronic dizzy. The coil -ve is spliced and then runs through the back of the 1600gt tacho and back to the coil again. Unsure if there is anything further back on the loom that could be a suppressor. Its currently reading around 3000 rpm at idle.

[Longboarder]

coil -ve is spliced and then runs through the back of the 1600gt tacho and back to the coil again.

Not sure that is a good idea. Usual routine is to give the rev counter a nice clean 12v ignition on positive supply, a good earth, and a signal wire from the coil negative. Those are the common three connections. Looping back to the coil is a no.

(Of course if your gauge is illuminated there will be a bulb with one or two wires to the lighting circuit.)

 

Nigel

[IanS]

Sounds like you have a very early transformer input lucas tacho.

Try changeing the number of turns through the input clip.

must be 30 years since I last used one of these.

[dandanfireman]

I'll have a look but i'm pretty sure the unit has a +12v feed and an earth. The part i'm talking about is the pulse lead that runs from the coil -ve. I'll check the smith instruments but i think thats ok. Sorry for any confusion.

[dandanfireman]

Any ideas?