need help
Thread Starter
2nd Gear
Joined: Jan 2016
Posts: 2
Likes: 0
need help
have a 86 vette and the fuel pump had to be replaced in the meantime I replaced the ecm,ign. control module and the tps. Now the instrument cluster panel is going off and on with different readings and being an auto. speedometer is reading a 35 mi. per hr. when engine is at op temp. what is the cause of this and what can I do. I replaced some relays and am still using the original prom that it came with.
Pro
Joined: Jan 2003
Posts: 706
Likes: 47
From: Denver Colorado
It seems that you have done too much electrical at once. My 1st try would be with the ecm. I believe you have a bad connection on the plugs that connect it to the main harness. Take it down, clean the plugs and the connections on the ecm with tuner or contact cleaner and try the instrument panel again. The TPS (Throttle Position Sensor) must be set using a VOM the procedure is in most manuals. The fuel pump and Ignition Control Module replacement probably have no relationship to the instrument panel issues. That instrument panel is one of the joys of C4 ownership. If yours worked prior to the ECM swap, the current problem is either connectivity or a malfunctioning ecm. Not clear to me why the spedo would register based on engine temp. It is supposed to sense pulses from a sensor on the transmission and the temp sensors are analog.
