tach not working

[screemin eagle]

im running 91 up style dsm ecu and harnes i wired the tach but its not working. im going to assume that a tach adapeter is needed can anyone confirm this?

[DJpowerHaus]

where did you tap into for the tach signal?

[screemin eagle]

Hello , still trying to get the tach worked out. I tried hooking it up to pin 109 on the ECU nothing. The I hooked it on one of the diagnostics connectors for the tach in the engine and it was showing 1/2 of the rpm
of what its supposed to be.

I am using a 91+ DSM harness on a 88 starion and trying to get the tach to work. Any ideas?

Thanks

[AllanL]

this might help: http://www.lilevo.com/turbo/tach/body_tach.html

is your coil pack the 3-pinsocket type and the power transistor is 8-pin?

you will need a tahc interface with this.

the earlier coil packs had 4-pin sokcets and the poweer transistors had 6-pins only...these were the coils with the tach interface.

the reason for your tach reading half the speed when you tap it to the engine speed detection connector is that it only reads 1 coil pack (for plugs 2 and 3, IIRC).

the tach interface will combine the signals of these two coils.

with the tach interface, you can hook up your tach to pin 109 of the ECU, or just grab wire from the tach interface and hook up your tach

hth

[screemin eagle]

Thanks for the input . You are right my coil pack does not have a tach interface.

I have a spare 90 coil pack somewhere I will give it a shot and let you know.


Thanks

[screemin eagle]

worked great thank you. I just spliced it straight to the tach.