Tacho won't work in 1990 SW turbo on Haltech ecu

Re: Tacho won't work in 1990 SW turbo on Haltech ecu (mymr2)

Sun, 22 Mar 2015 12:51:56 GMT

Hi Thanks all for the help..
The wiring guy said he didn't connect the tacho wire as the speedo is not working and the cluster lights are flickering. So once I have sorted those problems he will wire in the tacho and sort that for me. the cluster had LEDs so change them but have found the speedo cable doesn't appear to be working....oh no I just hope it is not the gear in the g/box... that looks a big job to do?
I will start a build post soon for those interested as this is an interesting car.

Re: Tacho won't work in 1990 SW turbo on Haltech ecu (MCT_MR2)

Fri, 20 Mar 2015 19:17:55 GMT

So your not running the standard coil/ignitor?

Toyota tachos in older cars are a negative driven tacho, not positive like a lot of other cars.

Two different methods are possible, depending on the car. Sometime you can tee in 12v to the tacho output wire with a 1k resistor to properly pull it up. This is probably not going to work in you case.

The other way is to use a relay. You need a relay that does not have a diode or a resistor. You feed 12v ignition to pin 86, and pin 85 goes to the output on your haltech that drives the tacho. The wire that goes to your tacho is tee'd in between the ecu and pin 85 of the relay. Pm robk and he should be able to send you a diagram.

Hope this helps

Re: Tacho won't work in 1990 SW turbo on Haltech ecu (mymr2)

Thu, 19 Mar 2015 20:31:44 GMT

Thanks number sent. Haltech platinum sport 1000

Re: Tacho won't work in 1990 SW turbo on Haltech ecu (S.Siri)

Tue, 17 Mar 2015 23:33:24 GMT

ill go grab my spare tacho...

Which haltech are u running? just want to compare settings to make sure my base settings are correct compared to other 3S's

BAH! ill PM u my number. shoot me a msg ill go over what u need to do

Re: Tacho won't work in 1990 SW turbo on Haltech ecu (S.Siri)

Tue, 17 Mar 2015 23:27:15 GMT

you gotta swap a resistor on the tacho board to a 10k resistor then you connect the tacho to a PWM output on the haltech then you can set the haltech to tacho output 12v pull up and i cant remember the percentage to get it to work but it about 10% duty off the top of my head.

BUT IF you are running stock igniter it should work with no mods as the output is on the stock igniter

im not a Mechanic or an auto elec.. cars are just and over obsessed hobby

Re: Tacho won't work in 1990 SW turbo on Haltech ecu (mymr2)

Tue, 17 Mar 2015 23:20:00 GMT

running duel channel ignitors

Re: Tacho won't work in 1990 SW turbo on Haltech ecu (5SGTE)

Sun, 15 Mar 2015 19:54:07 GMT

Pretty sure you'll need a tach adapter. What ignition are you using?

Tacho won't work in 1990 SW turbo on Haltech ecu (mymr2)

Sun, 15 Mar 2015 15:33:31 GMT

Just put in a Haltech ecu and tacho won't work. Was told but tuner runs off std ecu which is now gone. Also boost gauge not working. Any one know how to fix? Cheers.