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Subaru ECU with Autometer Tach.
flat_iv - December 28th, 2005 at 11:34 PM

Anyone ever hook up an Autometer tach with a Subaru ECU (95 Legacy 2.2)? I have mine hooked up to the ecu's output for the tach and the tach jumps to 7000 rpm's and does nothing when the car is running. Even if youi give the car gas it stays at 7000 rpm's. Any help would be appreciated.

Thanks,
Richard

subybug - December 29th, 2005 at 04:16 AM

Why not hook it up to the ignition coils and select it for 8 cils as the suby fires 2 cils simultanious

flat_iv - December 29th, 2005 at 04:23 AM

The 2.2 only has 1 coil pack. My coil pack has 3 wires. Which wire would you kook it up to?

[ Edited on 28/12/2005 by flat_iv ]

tassupervee - December 29th, 2005 at 10:53 AM

The "pack" contains basically 2 primary and 4 seperate secondary windings.
One wire will be +12v switched from the key and the other wires will be grounded Via the ECU coil triggers.
You should be able to probe the leads to find which one is +12V and then use either one of the 2 others to trigger your tach.
L8tr
E

pete wood - December 29th, 2005 at 03:00 PM

this system worked for me and cost 8c.

tassupervee - December 29th, 2005 at 09:25 PM

YerThats using a combined signal to fool the tach into looking at 4 pulses.
Cewl if you have a tach that is not switchable.
L8tr
E

pete wood - December 30th, 2005 at 08:43 AM

I have a switchable tach for 4/6/8 cyl it works fine.

flat_iv - December 30th, 2005 at 09:10 AM

I double checked that I have 12V and a good ground and that I have the correct wire out of the ECU. The tach is set for 4 cylinder. Is there any way I can check that I am getting the correct current from the ECU? I am going to remove the tach wires and hook it up to my Jetta to make sure the tach. works.

tassupervee - December 30th, 2005 at 10:25 AM

I can only suggest that the waveform from the ECU is incompatible with the Autometer tach.
Just try it on one of the coil trigger wires to prove it.
L8tr
E

speedster356 - December 30th, 2005 at 10:42 AM

Quote:

I can only suggest that the waveform from the ECU is incompatible with the Autometer tach.


Yup that's correct, you'll have to use the coil pulse not the ECU output.
Had the same problem on my setup.

flat_iv - December 31st, 2005 at 09:19 AM

Took the tach out and connected it strait to the battery and it did nothing. The Autometer tach's are suppose to reset its self to 0 rpm's when powered (even with out a tach signal). Mine stayed at 7000 rpm's. I called Autometer and he said it was faulty and for me to send it back to them to fix.

speedster356 - December 31st, 2005 at 09:59 AM

They may be able to modify it so it reads the ECU out signal, that may be an option.

flat_iv - December 31st, 2005 at 01:01 PM

I am pretty sure the signal from the ECU will work. In the ShopTalk Forum a fellow VW/Suby person has the same setup as I do and his tach. is reading Ok from the ECU.

pete wood - January 2nd, 2006 at 11:10 AM

what do you want an autometer tach for anyway. it's a rice boy gauge :P

just stirring.

I'm surprised that with such an expensive bit of kit, that you can't order an ECU friendly tach or coil friendly tach as seperate models. Might be worth talking to whoever imports them into Aust.

tassupervee - January 2nd, 2006 at 11:47 AM

Pete
Reading Flat-iv's reply, his tach appears dead.
I have the same tach in my ute and yer, unpowered the tach sits arouind 2000rpm or so, you put 12v to it and it flicks immediately to zero RPM.

So I agree with hbim that the tach sounds dodgey!

L8tr
E

flat_iv - January 2nd, 2006 at 11:48 AM

Easy Now.... The tach is ECU friendly. I took out the stock speedo and cloch and added black face speedo and tach. As you can see its not ricey and the interior isnt finished..Its a common ground from german workmanship to modern technology.