PCM Diagnostics & Tuning HP Tuners | Holley | Diablo

PCM and harness confusion???

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Old May 19, 2011 | 03:27 PM
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shorty(98TA)'s Avatar
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From: osawatomie ks
Default PCM and harness confusion???

I recently bought a 98 TA. When i got it the gas gauge and tach were not working. The SES light was on so I took it to my installer and had him run the codes, it was showing a fuel level sensor code and a EVAC code. So assumed the fuel guage not working was due the level sensor, and had a new fuel pump put in. Well the guage still doesnt work in our investigation of the problem we discovered that my car has a 99+ PCM and the harness matches the diagram for a 99+. Now I know that when swapping a 99+ PCM into a 98 car you have to change the Hz read out in the PCM to get the fuel guage to work (dont know how to do it but know thats what needs done).

So would the 99+ PCM and harness also be whats effecting the tach? If so how would I fix the problem? I also have a Autometer tach that will be going in the car how would this problem effect hooking it put? I havent been able to find a good wirring diagram for hooking put the Autometer

Any help would be great. Thanks
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Old May 19, 2011 | 05:00 PM
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From: Brenham
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The tach should work, may want to check and see if the pin isnt seated in the harness. Can you read the tach with a scan tool?
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Old May 19, 2011 | 05:08 PM
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From: osawatomie ks
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I really dont remember if we tried to read the tach with a scan tool. My real concern is this will affect the Autometer tach? Getting the stock tach to work isnt much of a concern because i plan to remove the stock culster and go with all aftermarket guages in the future
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Old May 20, 2011 | 09:45 PM
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From: osawatomie ks
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There is no tach out put from the PCM to the guage cluster... How the hell do I fix that?
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