e38 ecu speedo and tach problems
10-06-2009, 09:47 PM
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e38 ecu speedo and tach problems OK, so here are my issues on a 1994 Firebird with LY6 vvt motor and M12 t56 installed:
speedometer: I have my t56 VSS hooked into my e38 at the vss lo/high input (aka replicated TOS) on my ecu. I have the settings in the ECU (via hptuners) set to what would be factory on a normal f-body with 17" wheels. I looked up stock tune files and copied the settings over.
The problem is that when I drive, if I'm moving the needle on the speedo peggs or goes up REALLY sharply then peggs - i adjusted settings in hptuners and nothing seemed to change that behavior. When I stop, though, the needle on the speedo goes to zero... very weird!
The tach i have hooked directly to the tach output on the e38 ecu... but i get nothing, no activity of any kind - is there something I'm missing? I heard of people saying something about a 12v pull-up resistor but I can't find anything on it.
if anyone has any suggestions that'd be great - thanks!
speedometer: I have my t56 VSS hooked into my e38 at the vss lo/high input (aka replicated TOS) on my ecu. I have the settings in the ECU (via hptuners) set to what would be factory on a normal f-body with 17" wheels. I looked up stock tune files and copied the settings over.
The problem is that when I drive, if I'm moving the needle on the speedo peggs or goes up REALLY sharply then peggs - i adjusted settings in hptuners and nothing seemed to change that behavior. When I stop, though, the needle on the speedo goes to zero... very weird!
The tach i have hooked directly to the tach output on the e38 ecu... but i get nothing, no activity of any kind - is there something I'm missing? I heard of people saying something about a 12v pull-up resistor but I can't find anything on it.
if anyone has any suggestions that'd be great - thanks!
10-08-2009, 10:16 AM
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That's what I'm reading now. I'll try it tonight. I found your previous post about this. Do you have a specific resistor type that you'd recommend?
Last edited by mr220v; 10-08-2009 at 10:21 AM.
