Did I find my tach wire?

Printed From: the12volt.com
Forum Name: Car Security and Convenience
Forum Discription: Car Alarms, Keyless Entries, Remote Starters, Immobilizer Bypasses, Sensors, Door Locks, Window Modules, Heated Mirrors, Heated Seats, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=50569
Printed Date: May 05, 2024 at 10:14 AM

Topic: Did I find my tach wire?

Posted By: slush
Subject: Did I find my tach wire?
Date Posted: February 21, 2005 at 7:20 PM

Hey,

So unsatisfied as i am with tachless, i attempted to find my tach wire. Today i found a harness on the driver side of my 1993 mitsubishi diamante ES (WHITE/ black w/silver dots i believe)... when i unplugged the harness, I got no reading on my tachometer/fuel gage/basically anything in the instrument panel... so i thought great, i must have found it in this harness..

However after probing some of the wires going into the harness (from the source) I found one WHITE/ black wire (tach on my car is supposedly white or WHITE/ blue at the coil) which showed me something like 25V AC, and when i'd rev my engine it'd drop to like 24... 23.. etc. I put it on DC and it was reading 12v.. dropping to 11.. 10.. etc. Not sure if this is the wire or not. That was the only wire (if i remember correctly) that had fluxuation on that harness when i pressed on the gas.

Anyway, I'd appreciate an input anyone has on this... thanks in advance!

-Derek

Replies:

Posted By: jrilla
Date Posted: February 21, 2005 at 7:24 PM

Measure a tach source in AC volts and it typically reads between 1 and 6 volts AC. The AC volts should increase when you rev the engine.

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J Rilla

Owner/Installer

Posted By: slush
Date Posted: February 21, 2005 at 7:32 PM

actually now that i look at my dm, i was measuring at 200 on AC as that is the only option my DM has. So that would mean i was seeing around 2.6 VAC on that suspected tach wire at idle, and upon rev i was seeing 2.5...2.4...2.3... etc.

-Derek

Posted By: metaverse
Date Posted: February 21, 2005 at 9:25 PM

You can always go to the instrument cluster..guaranteed tach (assuming you have a guage)

Posted By: TJ92Civic
Date Posted: February 21, 2005 at 10:39 PM

TACHOMETER

WHITE/ blue or white

at coil pack

Thats what I found...

tim

Posted By: slush
Date Posted: February 22, 2005 at 1:51 AM

metaverse wrote:

You can always go to the instrument cluster..guaranteed tach (assuming you have a guage)

Well I technically did... although i didn't dig all the way up there, i found the harness that the instrument cluster uses for all of its electronics (tach/odometer/fuel gauge/engine temp/warning lights/etc.). I pulled it out and they all didnt' work anymore. I probed a white wire on that and saw it at 2.6 VAC while i was idle. When I pushed down on the gas, the voltage dropped... then went back up when i released the gas pedal. I was probing the wire with the red (+) lead and grounding the (-) lead to my chassis.

-Derek