Re: 93 camaro z28 Problem with speedometer!!!!
The 93 factory manual is contradictory with regard to the speedometer operation. In one place it describes a "VSS buffer" located in the under hood convenience center. The buffer is the device that converts the VSS output to the signal required by the speedometer. If that is correct, 1993 would be the only year that uses this configuration. Later years feed the VSS signal to the PCM, and the PCM drives the speedometer. 93 is different in many respects, with the tachometer driven directly off the coil, via a filter, where other years drive the tach from the PCM.
Yet elsewhere in the factory manual, the wiring diagrams show the VSS signal splitting and feeding both the ECM and the speedometer/odometer section of the cluster, and do not show a buffer.
Look in the under hood fuse/relay box to see if there is any indication of the VSS buffer.
Could be the VSS, could be the buffer (if it exists), could be the speedometer or could be high voltage interference on the VSS signal wires.
94 Formula A3+1: 381ci all-forged stroker - Callies Stealth, Oliver 5.85 billet rods, BME nitrous pistons / CNC LT4 heads / Comp Cams custom solid roller / TH400+GearVendors OD/4.11's / Strange 12-bolt / 300-shot N2O / Spohn Suspension / 6-pt roll bar with integrated SFC's / full AutoMeter instrumentation / MoTeC M48 Pro engine management system / a few other odds 'n ends. 800HP/800LB-FT at the flywheel.
Last edited by Injuneer; 11-12-2013 at 07:33 AM.