auto meter tach
02-12-2009, 10:07 PM
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auto meter tach when installing do you have to cut the brown or orange wire on the back for some reason mine is not reading right it's like 1k above my factory one
02-14-2009, 08:58 AM
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+1 the instrument cluster tach signal, the white wire, from the PCM (C1 the red one, pin 13). I tapped mine at the PCM connector, its only a signal for the cluster so it will not effect any engine rpm reading the computer needs.
02-14-2009, 11:09 AM
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OK so is it better to hook it up on the coil ?? if so what wire i had mine hooked up to pcm but for some reason it made the fuel pump cut off so i dissconnected the tach
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02-14-2009, 01:14 PM
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?
BTW my application was getting RPM to a racepak unit.
that white wire on the PCM sole purpose on the car is to get a tach signal to your dash. Thats why I did not even contemplate going to any other sources for a rpm signal. So to answer your question I think it's better to get from the PCM. as to why your fuel pump would cut out, you might of messed up the fuel enable that is on the same connector and wire bundle as the instrument cluster tach sig at the PCM.
BTW my application was getting RPM to a racepak unit.
that white wire on the PCM sole purpose on the car is to get a tach signal to your dash. Thats why I did not even contemplate going to any other sources for a rpm signal. So to answer your question I think it's better to get from the PCM. as to why your fuel pump would cut out, you might of messed up the fuel enable that is on the same connector and wire bundle as the instrument cluster tach sig at the PCM.
02-14-2009, 02:01 PM
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BLUE WIRE CUT THE BLUE WIRE DAMNIT!
Sorry had to. I'd much prefer the coil signal over the PCM's. Reason, being your signal from the PCM is most likely going to be different from the actual RPM simply due to all the processing and changes in electrical signal after passing through the PCM. Everyone says their Tachs in F-Bodies are 100rpms off, yet my tach is DEAD ON THE NUTS! Maybe it's because I have a 93 and no PCM, which I think the RPM is direct from the coil (or just a pass-through in the ECM) as when I hook my scanner up to the ECM and run down the road it's right on with my tach.
Anyways, that's just my $.02
Sorry had to. I'd much prefer the coil signal over the PCM's. Reason, being your signal from the PCM is most likely going to be different from the actual RPM simply due to all the processing and changes in electrical signal after passing through the PCM. Everyone says their Tachs in F-Bodies are 100rpms off, yet my tach is DEAD ON THE NUTS! Maybe it's because I have a 93 and no PCM, which I think the RPM is direct from the coil (or just a pass-through in the ECM) as when I hook my scanner up to the ECM and run down the road it's right on with my tach.
Anyways, that's just my $.02
02-15-2009, 10:55 AM
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BLUE WIRE CUT THE BLUE WIRE DAMNIT!
Sorry had to. I'd much prefer the coil signal over the PCM's. Reason, being your signal from the PCM is most likely going to be different from the actual RPM simply due to all the processing and changes in electrical signal after passing through the PCM. Everyone says their Tachs in F-Bodies are 100rpms off, yet my tach is DEAD ON THE NUTS! Maybe it's because I have a 93 and no PCM, which I think the RPM is direct from the coil (or just a pass-through in the ECM) as when I hook my scanner up to the ECM and run down the road it's right on with my tach.
Anyways, that's just my $.02
Sorry had to. I'd much prefer the coil signal over the PCM's. Reason, being your signal from the PCM is most likely going to be different from the actual RPM simply due to all the processing and changes in electrical signal after passing through the PCM. Everyone says their Tachs in F-Bodies are 100rpms off, yet my tach is DEAD ON THE NUTS! Maybe it's because I have a 93 and no PCM, which I think the RPM is direct from the coil (or just a pass-through in the ECM) as when I hook my scanner up to the ECM and run down the road it's right on with my tach.
Anyways, that's just my $.02
