tach signal too low

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=124452
Printed Date: May 14, 2025 at 2:31 PM

Topic: tach signal too low

Posted By: anfoman76
Subject: tach signal too low
Date Posted: November 14, 2010 at 5:51 PM

Hi guys long time lurker first time poster. In need of help I have installed a prostart ct3460 in my 1995 gmc 2500diesel. The problem is my tach signal is too low for the module to learn it. I need at least 1.8 volts and I only have .14 volts at idle. Can anyone give me some suggestions. Could I just hook it up to a 12volt while running wire? any help would be appreciated.

Replies:

Posted By: chev104275
Date Posted: November 14, 2010 at 6:03 PM

DEI 454T

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If i Can't Install it I Don't need it Joe

Posted By: anfoman76
Date Posted: November 14, 2010 at 6:42 PM

Could I just use the tach signal to trip a relay?

Posted By: t&t tech
Date Posted: November 14, 2010 at 7:07 PM

chev104275 wrote:

DEI 454T

Posted By: anfoman76
Date Posted: November 14, 2010 at 7:15 PM

t&t tech wrote:

chev104275 wrote:

DEI 454T

X2

Ok that would be great if I could find one in this little backwoods town I live in in Canada. Or if i could find one on the internet where I am not going to pay twice the price of the unti for shipping. I'm gonna try the relay. I don't get a tach signal until it's actually running because my tach signal is generated by my alternator. So if I use that signal to trip a relay with 5-6volts to it, it should tell my remote starter that it's running. Thanks for your help guys.

Posted By: anfoman76
Date Posted: November 14, 2010 at 7:23 PM

I found one with reasonable shipping :) I am going to buy it but it could take up to a month to get here. Could my theory on the raly work?

Posted By: kreg357
Date Posted: November 14, 2010 at 7:57 PM

Just in case the mail is slow and it gets too cold.

Which Tach wire are you connecting to? Bulldog suggests the White tach wire at the instrument cluster.
NOTE *3 THE DIESEL TACH wire is also a WHITE but at the Instrument Cluster.
Verify the wire with a DMM set to 20v AC.

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Soldering is fun!

Posted By: KPierson
Date Posted: November 14, 2010 at 11:45 PM

A relay off your fuel injector won't work.

As asked above, where are you trying to get the tach signal from?

I would try to just connect the tach wire to the fuel injector directly if you don't want to wait on the part.

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Kevin Pierson

Posted By: awdeclipse
Date Posted: November 15, 2010 at 2:12 AM

Is that truck a common rail?