lt1 tach signal from pcm vs. direct from coil question
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lt1 tach signal from pcm vs. direct from coil question
Hi guys,
I'm running a 1995 camaro lt1 w/ lt1 t56 in my old 1984 Jaguar xj6.
I've been wrestling with figuring out just how to get a tach signal into my tach via the PCM -- I haven't tried just tapping into the wire at the coin and running that wire to the cab yet because A) it's kind of a hassle and b) I already should (in theory) have a filtered tach reading from my PCM. The tach feed is from pin a13 on the red (A) connector.
Is the tach feed from the PCM a logic driven signal (ie, too weak to run the tach) or is it the same feed that i'd be getting from the coil? Im confused because the tach isn't moving AT ALL!
Any illumination would be great,
Tyler W.
I'm running a 1995 camaro lt1 w/ lt1 t56 in my old 1984 Jaguar xj6.
I've been wrestling with figuring out just how to get a tach signal into my tach via the PCM -- I haven't tried just tapping into the wire at the coin and running that wire to the cab yet because A) it's kind of a hassle and b) I already should (in theory) have a filtered tach reading from my PCM. The tach feed is from pin a13 on the red (A) connector.
Is the tach feed from the PCM a logic driven signal (ie, too weak to run the tach) or is it the same feed that i'd be getting from the coil? Im confused because the tach isn't moving AT ALL!
Any illumination would be great,
Tyler W.
Joined: Apr 2005
Posts: 7,736
Likes: 14
From: Not in Kansas anymore
Car: 82 Z28
Engine: 383 SP EFI/ 4150 TB
Transmission: T400
Axle/Gears: QP 9" 3.73
Re: lt1 tach signal from pcm vs. direct from coil question
Might get better advise on a LT1 forum
http://www.camaroz28.com/forums/forumdisplay.php?f=9
Last edited by vetteoz; Aug 22, 2011 at 06:32 AM.
Re: lt1 tach signal from pcm vs. direct from coil question
You'll have to add a wire on the coil to draw it directly from with the LT1. LT1 cars usually dont have a problem with tach signal, only LS1s in very sensitive tachs. For those use a booster wire and a resistor to bump the signal voltage up. Not real sure how your jag works
Junior Member
Joined: Nov 2015
Posts: 58
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From: Kansas City
Car: 1984 &1987 Firebird, 1991 GTA
Engine: 5.0(84) , 5.7L LT1 (87),5.0(91)
Transmission: Automatic
Axle/Gears: 3.23;3.42;2.73
Re: lt1 tach signal from pcm vs. direct from coil question
Hi guys,
I'm running a 1995 camaro lt1 w/ lt1 t56 in my old 1984 Jaguar xj6.
I've been wrestling with figuring out just how to get a tach signal into my tach via the PCM -- I haven't tried just tapping into the wire at the coin and running that wire to the cab yet because A) it's kind of a hassle and b) I already should (in theory) have a filtered tach reading from my PCM. The tach feed is from pin a13 on the red (A) connector.
Is the tach feed from the PCM a logic driven signal (ie, too weak to run the tach) or is it the same feed that i'd be getting from the coil? Im confused because the tach isn't moving AT ALL!
Any illumination would be great,
Tyler W.
I'm running a 1995 camaro lt1 w/ lt1 t56 in my old 1984 Jaguar xj6.
I've been wrestling with figuring out just how to get a tach signal into my tach via the PCM -- I haven't tried just tapping into the wire at the coin and running that wire to the cab yet because A) it's kind of a hassle and b) I already should (in theory) have a filtered tach reading from my PCM. The tach feed is from pin a13 on the red (A) connector.
Is the tach feed from the PCM a logic driven signal (ie, too weak to run the tach) or is it the same feed that i'd be getting from the coil? Im confused because the tach isn't moving AT ALL!
Any illumination would be great,
Tyler W.
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JeremyNYR
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