1992-1999 Series I L27 (1992-1994 SE,SLE, SSE) & Series II L36 (1995-1999 SE, SSE, SLE) and common problems for the Series I and II L67 (all supercharged models 92-99) Including Olds 88's, Olds LSS's and Buick Lesabres Please use General Chat for non-mechanical issues, and Performance and Brainstorming for improvements.

Where to tap in for external Tach?

Thread Tools
 
Search this Thread
 
Old Feb 24, 2008 | 10:47 AM
  #1  
Bonneville92V688's Avatar
Thread Starter
Junior Member
 
Joined: Apr 2006
Posts: 0
Likes: 0
From: Purgatory
Bonneville92V688 is on a distinguished road
Default Where to tap in for external Tach?

Ok, so I am wanting to verify if the tach in my Bonne is off to determine if I actually ahve a high idle problem, so I have a Sunpro Super tach II laying here that I want to hook up to determine this. Where is the best place to hook it up? I know the white wire on the ICM harness is the tach wire, as I used the same one to tap into on my '94 Century and '96 Ciera. But, is there a easier way than cutting into the wire? TIA!
Reply
Old Feb 24, 2008 | 10:52 AM
  #2  
sandrock's Avatar
Senior Member
True Car Nut
 
Joined: Aug 2004
Posts: 3,067
Likes: 1
From: In your garage, swipin' da lug nutz
sandrock is on a distinguished road
Default

Not an easier way that I know of. You could use a vampire tap (or clamshell splice), under the fusebox cover in the engine compartment. That would be the most protected place that I can think of. Or, backprobe the white wire at the ICM connector with a paperclip.
Reply
Old Feb 24, 2008 | 10:57 AM
  #3  
Bonneville92V688's Avatar
Thread Starter
Junior Member
 
Joined: Apr 2006
Posts: 0
Likes: 0
From: Purgatory
Bonneville92V688 is on a distinguished road
Default

Hmmm....think you can show me the area to tap in under the fusebox cover? It would be appreciated.
Reply
Old Feb 24, 2008 | 11:04 AM
  #4  
sandrock's Avatar
Senior Member
True Car Nut
 
Joined: Aug 2004
Posts: 3,067
Likes: 1
From: In your garage, swipin' da lug nutz
sandrock is on a distinguished road
Default

Not while I am at work...but it should be easy enough to trace if you have a meter that shows you continuity. You will want to place one of those probes where the ICM harness connects to the main harness, and the other will have to be the prober for the white wire going into the firewall harness.
Reply
Old Feb 24, 2008 | 11:16 AM
  #5  
willwren's Avatar
Junior Member
Posts like a Ricer Type-R
 
Joined: Aug 2002
Posts: 11
Likes: 13
willwren is on a distinguished road
Default

Use your scantool to see what your RPM'* really are.
Reply
Old Feb 24, 2008 | 11:42 AM
  #6  
Bonneville92V688's Avatar
Thread Starter
Junior Member
 
Joined: Apr 2006
Posts: 0
Likes: 0
From: Purgatory
Bonneville92V688 is on a distinguished road
Default

I don't get a tach reading on the scantool. :(
Reply
Old Feb 24, 2008 | 02:35 PM
  #7  
willwren's Avatar
Junior Member
Posts like a Ricer Type-R
 
Joined: Aug 2002
Posts: 11
Likes: 13
willwren is on a distinguished road
Default

If you have the CP9110, you do. Look again.
Reply
Old Feb 24, 2008 | 03:05 PM
  #8  
clm2112's Avatar
Junior Member
 
Joined: May 2006
Posts: 0
Likes: 0
From: BonnevilleHell
clm2112 is on a distinguished road
Default Re: Where to tap in for external Tach?

Originally Posted by Bonneville92V688
I know the white wire on the ICM harness is the tach wire, as I used the same one to tap into on my '94 Century and '96 Ciera. But, is there a easier way than cutting into the wire? TIA!
It'* the same wire. If you want to hook the tach up somewhere more or less permanetly, then trace that wire back as far as it goes in the harness and tap in there. I don't use "vampire" taps. My taste is to take the pin out of the existing connector shell and solder another wire on the same connector (so two wires come out the shell where there used to be just one.) That way I never need worry about the tap cutting the existing lead. When I did the tach on the '90 Bonnie, I didn't even have to do that...the tach wire dead-ended where the ignition wiring met up with the rest of the harness..I had to add the missing pin.

BTW, does your tach have setings for a V6? The tach signal is only going to be 3 pulses per revolution, not the 4 pulses of a V8 (which most aftermarket tachs come configured for.)

If you just want a place to test the tach signal comming out of the ignition, stick a straight pin into shell from the back (parrallel to the wire)...that way you can touch the contacts inside the shell without disturbing the wires.
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
dms3reno
1992-1999
3
Sep 27, 2003 10:38 AM
Wolfedog50
1992-1999
12
Sep 18, 2003 12:57 AM
95naSTA
1992-1999
12
May 25, 2003 02:30 AM
Kuhl
General GM Chat
5
May 16, 2003 04:47 PM
95naSTA
1992-1999
12
Apr 23, 2003 06:50 PM




All times are GMT -4. The time now is 10:33 PM.