1998 2.5rs tach wire - Subaru Impreza GC8 & RS Forum & Community: RS25.com

turboed22 · 05-22-2009, 04:14 PM

Does the ecu have a tach wire signal coming from it? I need to put a new signal from my standalone into the tach. If there is one coming from the ecu to the gauge, I was gonna snip it and run my tach-output through it.

Car is a 1998 RS

Thanks

subidoo · 05-25-2009, 10:19 PM

off topic what standalone are you running if you dont mind me asking?

turboed22 · 05-25-2009, 10:24 PM

Quote:

Originally Posted by subidoo

off topic what standalone are you running if you dont mind me asking?

Megasquirt

**OBSmines2010** · 05-25-2009, 11:02 PM

Here is a link with ECU pinouts.
NorthUrsalia.com: Wiring Diagrams And ECU Pinouts
I could not find what you were looking for. I might have missed it though.

XanRules · 05-25-2009, 11:44 PM

On my car - a 97 OBS, it's a red wire on pin 21. I have a 98 wiring harness somewhere, let me see if I can rig it all up and figure it out.

Storm · 05-26-2009, 03:29 AM

There is.....it's labeled as the "engine speed signal". Don't snip it....just tap into it.

turboed22 · 05-26-2009, 10:48 AM

Quote:

Originally Posted by Storm

There is.....it's labeled as the "engine speed signal". Don't snip it....just tap into it.

See that is what I thought but it didnt work. I will need to try it agian and make sure everything is correct.

My motor would not start when I snipped it but it made my megasquirt all messed up when I tapped into it. What does this do if it is snipped? I am very confused as the motor is being controlled by the megasquirt.

Storm · 05-26-2009, 11:40 AM

You may need to configure the MS to recognize the crank sensor signal as a tach signal (with the appropriate deductions for toothcount, etc....).

turboed22 · 05-26-2009, 12:05 PM

Quote:

Originally Posted by Storm

You may need to configure the MS to recognize the crank sensor signal as a tach signal (with the appropriate deductions for toothcount, etc....).

Yeah that is what it is set-up as now. I am running the 36-2-2-2 wheel found on some later Subaru models. It looks like I might a different configuration issue with the wire I was sending the pulse signal to.

Just making sure:
What I am doing here is getting my factory tach to work again. Because there is no signal from the ECU, I need to get a signal to it.

**kay95** · 05-26-2009, 01:00 PM

MS-Extra Manual Index

Try this circuit. The stock tach is low current 12V. Use pin 10 off the PIC(40pin micro controller). This is perfect then run that jumper to either spout 3/4 or one of the IAC output and if all of those are used cut one of the ground leads solder to that then pot it for strain relief.

05-22-2009, 04:14 PM	#1 (permalink)
turboed22 2.0L Turbo Car: Black 1998 2.5RS-T Fav Mod: Megasquirt EMS My: Subaru Parts for sale Join Date: Aug 2004 Location: Golden / Arvada, CO Trader Rating: (0) Posts: 1,598	1998 2.5rs tach wire Does the ecu have a tach wire signal coming from it? I need to put a new signal from my standalone into the tach. If there is one coming from the ecu to the gauge, I was gonna snip it and run my tach-output through it. Car is a 1998 RS Thanks __________________ --Scott MS'ed 1998 2.5RS-T

05-25-2009, 11:02 PM	#4 (permalink)
OBSmines2010 Katy Perry Car: 2001 Outback Sport-Turbo Fav Mod: Suspension My: Subaru Parts for sale Join Date: Jun 2007 Location: Fort Collins, Colorado Trader Rating: (13) Posts: 3,266	Here is a link with ECU pinouts. NorthUrsalia.com: Wiring Diagrams And ECU Pinouts I could not find what you were looking for. I might have missed it though. __________________ Mark My Flickr Page

05-25-2009, 11:44 PM	#5 (permalink)
XanRules 3.3L Car: 97 GF8 Fav Mod: Not Being Retarded My: Subaru Parts for sale Join Date: Dec 2007 Location: Atlanta, GA Trader Rating: (4) Posts: 699	On my car - a 97 OBS, it's a red wire on pin 21. I have a 98 wiring harness somewhere, let me see if I can rig it all up and figure it out. __________________ Correct Fitment Crew: Because Only Turds Should be Dumped and Flushed.

05-26-2009, 03:29 AM	#6 (permalink)
Storm 2.5L RS-T My: Subaru Parts for sale Join Date: Dec 2001 Location: NE Ohio Trader Rating: (22) Posts: 6,365	There is.....it's labeled as the "engine speed signal". Don't snip it....just tap into it. __________________ Jay Storm

05-26-2009, 11:40 AM	#8 (permalink)
Storm 2.5L RS-T My: Subaru Parts for sale Join Date: Dec 2001 Location: NE Ohio Trader Rating: (22) Posts: 6,365	You may need to configure the MS to recognize the crank sensor signal as a tach signal (with the appropriate deductions for toothcount, etc....). __________________ Jay Storm

05-25-2009, 10:19 PM	#2 (permalink)
subidoo 1.8L Car: 1999, Rsti, rally blue My: Subaru Parts for sale Join Date: May 2009 Trader Rating: (0) Posts: 6	off topic what standalone are you running if you dont mind me asking?

05-26-2009, 01:00 PM	#10 (permalink)
kay95 Premium Member Car: 95 L, 96 OUTBACK Fav Mod: p1 SUSPENSION My: Subaru Parts for sale Join Date: Jul 2004 Location: glen rock PA Trader Rating: (1) Posts: 2,559	MS-Extra Manual Index Try this circuit. The stock tach is low current 12V. Use pin 10 off the PIC(40pin micro controller). This is perfect then run that jumper to either spout 3/4 or one of the IAC output and if all of those are used cut one of the ground leads solder to that then pot it for strain relief. Attached Thumbnails

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