Help with Speedometer and Tach, please!
Thread Starter
Teching In
Joined: Feb 2005
Posts: 10
Likes: 0
From: Burgaw, NC
Help with Speedometer and Tach, please! Hello,
Ok, I have installed a Pontiac engine w/MPFI custom injection system in my TA. Originally a LT car, but we had to use a 90 Corvette OBD1 computer. The install looks factory, so much so that Die-Hard Pontiac people mistake it for a LT/LS car, but my problem is I haven't yet figured out how to make the factory Speedometer and Tach work. I know that the LT was crank-triggered and the siginal is probabbly voltage going to instrument cluster. Any ideas how to convert since we are using a lead from the coil? Speedometer I think is 4000/pulses in the LT car and also in the Corvette computer, but our initial attempt to connect didn't seem to work. Any ideas?
Any help greatly appreciated!
Jimmy Carter
Ok, I have installed a Pontiac engine w/MPFI custom injection system in my TA. Originally a LT car, but we had to use a 90 Corvette OBD1 computer. The install looks factory, so much so that Die-Hard Pontiac people mistake it for a LT/LS car, but my problem is I haven't yet figured out how to make the factory Speedometer and Tach work. I know that the LT was crank-triggered and the siginal is probabbly voltage going to instrument cluster. Any ideas how to convert since we are using a lead from the coil? Speedometer I think is 4000/pulses in the LT car and also in the Corvette computer, but our initial attempt to connect didn't seem to work. Any ideas?
Any help greatly appreciated!
Jimmy Carter
Moved to conversions and hybrids.
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2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
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2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
Thread Starter
Teching In
Joined: Feb 2005
Posts: 10
Likes: 0
From: Burgaw, NC
Sorry, Kind of important info! 1994 TA, reskinned to 2002 body panels. T56 transmission. Unfortunately, we began this conversion in 2001, and back then there were not many options on controling a non-stock MPFI. The best we could find then was the 1990 OBDI computer. Today we would have used the OBDII and all the nagging little problems would be non-issues.
Thanks for any help.
Jimmy
Thanks for any help.
Jimmy
Joined: Sep 2004
Posts: 3,148
Likes: 12
From: Downers Grove, IL
I checked into the clusters and the 2000 one will not work, it uses serial data for the tach signal which would be a pain to replicate.
The 1996 one looks like it would be relatively easy to hook up and depending on what kind of ignition system you have it may be a direct wire up. I would need a wiring diagram for it to be able to figure out for sure. I found 2 wiring diagrams for a 95, one was for a z28 and the other a formula and the pins were in different positions, so I don`t want to make a recommendation until I see a wiring diagram for a 96.
Anyone have a wiring diagram for a 96 TA dash cluster?
The 1996 one looks like it would be relatively easy to hook up and depending on what kind of ignition system you have it may be a direct wire up. I would need a wiring diagram for it to be able to figure out for sure. I found 2 wiring diagrams for a 95, one was for a z28 and the other a formula and the pins were in different positions, so I don`t want to make a recommendation until I see a wiring diagram for a 96.
Anyone have a wiring diagram for a 96 TA dash cluster?
Trending Topics
oh wait! a 98+ tach/cluster wont work on my 95 LT1 is the understanding that I have made from your previous post! No way at all? I believe my friend over at GM has the diagram you need, ill get it for you in the AM
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Verdad Gallardo Joined: Sep 2004
Posts: 3,148
Likes: 12
From: Downers Grove, IL
Based on the diagrams that I was able to find I don`t think the 98+ dash cluster will work. At least not in a direct plug in way, I`m sure that someone out there could make a convertor to convert your tach signal into a serial data signal so that the dash would work, but I don`t know of one that is currently available right now.
Thread Starter
Teching In
Joined: Feb 2005
Posts: 10
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From: Burgaw, NC
Hello OldSchool! You have a nice looking Formula. Please do not misunderstand, the LS platform is an unbelieveable powerplant, we have one in a '66 Chevy II wagon. But in my opinion, it has no place in a rare Pontiac. For the same reason, aftermarket gauges have no place in a showcar that was built to look like a stock-appearing TA. We used Autometer gauges in a custom dash cluster while testing, but once the car was completed and ready to show they had to go.
TECH Regular
Joined: May 2005
Posts: 406
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From: Bay Area, CA
Originally Posted by goatkeeper
Hello OldSchool! You have a nice looking Formula. Please do not misunderstand, the LS platform is an unbelieveable powerplant, we have one in a '66 Chevy II wagon. But in my opinion, it has no place in a rare Pontiac. For the same reason, aftermarket gauges have no place in a showcar that was built to look like a stock-appearing TA. We used Autometer gauges in a custom dash cluster while testing, but once the car was completed and ready to show they had to go.
Besides, it's worth more money now.
