tach not working??!!
tach not working??!! I am using the factory (1972 GMC Jimmy) Dash bezel and gauges. I have everything working (I believe, don't have a scanner yet) except the tach. I hooked the tach wire from my 1972 tach harness to the wire marked tach and I ran a power wire to the tach just like it was and working before the swap. The engine starts and runs fine, no MIL/CEL while running but the factory 1972 tach is not moving. The engine is a 2005 5.3 and the PCM has blue/green connectors.
What can we do to get my tach working.
What PCM pin should be my tach signal?
Thanks
Mark
I don't know the settings in the PCM as I did not do the tuning. I have a PM to the tuner and I will post what he has to say but thought I would ask the knowledgeable members also.
What can we do to get my tach working.
What PCM pin should be my tach signal?
Thanks
Mark
I don't know the settings in the PCM as I did not do the tuning. I have a PM to the tuner and I will post what he has to say but thought I would ask the knowledgeable members also.
On The Tree
Joined: Feb 2009
Posts: 130
Likes: 0
From: san antonio tx
when I did mine,, I am using a autometer tach,,, I had to use the resistor to the "tach" line from the pcm to the tach, just use the resistor you mentioned, and plug one side to the tach wire and the other side of the resistor to a 12v ing. mine has worked, but when at idle my needle moves up and down just as if I had a big lobe cam in the engine., but it only does it at idle...
Teching In
Joined: Mar 2008
Posts: 29
Likes: 0
From: La Canada, California
tach signal I am using the factory (1972 GMC Jimmy) Dash bezel and gauges. I have everything working (I believe, don't have a scanner yet) except the tach. I hooked the tach wire from my 1972 tach harness to the wire marked tach and I ran a power wire to the tach just like it was and working before the swap. The engine starts and runs fine, no MIL/CEL while running but the factory 1972 tach is not moving. The engine is a 2005 5.3 and the PCM has blue/green connectors.
What can we do to get my tach working.
What PCM pin should be my tach signal?
Thanks
Mark
I don't know the settings in the PCM as I did not do the tuning. I have a PM to the tuner and I will post what he has to say but thought I would ask the knowledgeable members also.
What can we do to get my tach working.
What PCM pin should be my tach signal?
Thanks
Mark
I don't know the settings in the PCM as I did not do the tuning. I have a PM to the tuner and I will post what he has to say but thought I would ask the knowledgeable members also.
Here is one product that I found (haven't used it):
http://www.nookandtranny.com/mm5/mer...ry_Code=GAUGES
For myself, I just purchased two aeroforce OBDII gauges:
http://www.aeroforcetech.com/
I haven't installed them yet, but if they work as advertised, they will display RPM, water temp, and anything else that the OBDII knows about and you can set 'alarm' values.
I believe that the tach signal produced by the PCM is a digital signal and can't be fed directly to an analog tachometer.
I believe that the tach signal produced by the PCM is a digital signal and can't be fed directly to an analog tachometer.
Here is one product that I found (haven't used it):
http://www.nookandtranny.com/mm5/mer...ry_Code=GAUGES
For myself, I just purchased two aeroforce OBDII gauges:
http://www.aeroforcetech.com/
I haven't installed them yet, but if they work as advertised, they will display RPM, water temp, and anything else that the OBDII knows about and you can set 'alarm' values.
Here is one product that I found (haven't used it):
http://www.nookandtranny.com/mm5/mer...ry_Code=GAUGES
For myself, I just purchased two aeroforce OBDII gauges:
http://www.aeroforcetech.com/
I haven't installed them yet, but if they work as advertised, they will display RPM, water temp, and anything else that the OBDII knows about and you can set 'alarm' values.
The tach signal can be sent to a standard tach direct from the PCM but the tach has to be set for 4 cylinder (yes weird I know). The Dakota Digital box is for people who can't or won't change the tach (or with factory or vintage instruments like Alien and I) and don't have access to change the output in their tune. Originally I installed one on my car but the tach output was fine, just incorrect. Now that I have tune software I could change the output in the tune but the box is already wired in and hidden so...
If I remember The Alien's build he is like me and trying to keep the factory feel about the interior so that solution won't work - but it looks cool in a high tech way.
Alien, you may have to do the resistor trick to get the tach working since your PCM is newer than 2003.
Trending Topics
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Topdon ONE vs. Artidiag 800 BT2: Which is the Diagnostic Tablet For You?
Pouria Savadkouei
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
I installed the resistor and my Tach now works but reads low. I guess I have to buy HP tuners or get someone to let me use theirs and buy a couple of credits to adjust the output in the PCM?
Option 2 is using the Dakota Digital converter box. It will allow you to change the 4 cyl factory output to V8 (or anything you need it to be) to match your factory style tach.
Teching In
Joined: May 2016
Posts: 5
Likes: 0
Need help with tach i have a 69 suburban that I swapped an 2002 5.3 4L60E motor in my suburban came with the factory tach I'd like to keep it I saw a guy at the Pomona swap meet in December an he got his factory gauges tach speedo to work he used the black box for speedo but I don't remember what he used for tach please help I want to keep my dash original. Thanks
i have a 69 suburban that I swapped an 2002 5.3 4L60E motor in my suburban came with the factory tach I'd like to keep it I saw a guy at the Pomona swap meet in December an he got his factory gauges tach speedo to work he used the black box for speedo but I don't remember what he used for tach please help I want to keep my dash original. Thanks
Andrew
