Tachometer accuracy with "tuner prom"
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Joined: Sep 2003
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Tachometer accuracy with "tuner prom"
My ZR1 has a PROM by "SOMEONE" installed and I ran it against a TECH1 for cluster validation with temp gauges etc. The cluster tach reads about 24% high all through the RPM range. The PROM that is installed has no physical ID's and I can see the fans, cags and probably the rev limiter has been modified.
Is the tach error something that could be the result of the PROM mod? Cluster rebuilders seem to agree that tach error could be +-5% but feel this is likely a problem somewhere else. If it were a conventional ignition a filter might be a solution but on a DIS that seems not to be an option. The PROM ID on the TECH1 is 2457 which I seem not to be able to identify either.
Is there someone in the Northern Va area that could verify the prom mods or do I just need to start fresh? Do you just install a stock PROM and check for results? HELP!!!!!!!
Is the tach error something that could be the result of the PROM mod? Cluster rebuilders seem to agree that tach error could be +-5% but feel this is likely a problem somewhere else. If it were a conventional ignition a filter might be a solution but on a DIS that seems not to be an option. The PROM ID on the TECH1 is 2457 which I seem not to be able to identify either.
Is there someone in the Northern Va area that could verify the prom mods or do I just need to start fresh? Do you just install a stock PROM and check for results? HELP!!!!!!!
Le Mans Master
Joined: Jan 2003
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From: Portland Oregon
Originally Posted by WVZR1
My ZR1 has a PROM by "SOMEONE" installed and I ran it against a TECH1 for cluster validation with temp gauges etc. The cluster tach reads about 24% high all through the RPM range. The PROM that is installed has no physical ID's and I can see the fans, cags and probably the rev limiter has been modified.
Is the tach error something that could be the result of the PROM mod? Cluster rebuilders seem to agree that tach error could be +-5% but feel this is likely a problem somewhere else. If it were a conventional ignition a filter might be a solution but on a DIS that seems not to be an option. The PROM ID on the TECH1 is 2457 which I seem not to be able to identify either.
Is there someone in the Northern Va area that could verify the prom mods or do I just need to start fresh? Do you just install a stock PROM and check for results? HELP!!!!!!!
Is the tach error something that could be the result of the PROM mod? Cluster rebuilders seem to agree that tach error could be +-5% but feel this is likely a problem somewhere else. If it were a conventional ignition a filter might be a solution but on a DIS that seems not to be an option. The PROM ID on the TECH1 is 2457 which I seem not to be able to identify either.
Is there someone in the Northern Va area that could verify the prom mods or do I just need to start fresh? Do you just install a stock PROM and check for results? HELP!!!!!!!
Thread Starter
Team Owner
Joined: Sep 2003
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That's kind of why I'm here, a couple cluster service reps seem to feel that there's very little likelyhood that it's a cluster problem with the 24% error and suggested looking into the prom or ecm.
I'm going to use a stock prom and validate it again against the TECH1 again. It's considerably less expensive to try the prom before removing the cluster for a checkout. There's a bit of a stumble or surge in mid RPM's with a steady throttle that maybe the stock prom would eliminate some of the diagnostics there also.
Thanks for your advice and I'll likely end up with it sent out any way!
The tach error at 24% if you did gear ratio, MPH calculations indicated that it had a pretty "stiff" gear but it didn't launch like it did. This was the initial reason for doing the validation
I'm going to use a stock prom and validate it again against the TECH1 again. It's considerably less expensive to try the prom before removing the cluster for a checkout. There's a bit of a stumble or surge in mid RPM's with a steady throttle that maybe the stock prom would eliminate some of the diagnostics there also.
Thanks for your advice and I'll likely end up with it sent out any way!
The tach error at 24% if you did gear ratio, MPH calculations indicated that it had a pretty "stiff" gear but it didn't launch like it did. This was the initial reason for doing the validation
