C5Z Tach Inop
Thread Starter
Racer
Joined: Jun 2017
Posts: 401
Likes: 79
From: Northeast PA
C5Z Tach Inop
Before tearing the wiring inside the fender apart, wanted to ask my peeps about their experience on this...
Tach doesn't work, but does do the full sweep on startup- the IPC engine speed code is there, & my question relates to the white RPM signal wire from PCM, & if the tach sweeps at startup, then where is that signal coming from if the path from PCM is broken? In know all the guages sweep at startup, but all of others work fine. I suspect it's that #10 white wire broken in the wire loom under the battery, probably from the same ancient battery leakage event that ate through the vacuum hose by the frame rail. Just felt it'd wise to get that 2nd or 3rd opinion on this before I contort this old body again to try to get to that rascal... getting to old for crawling under cars!!
Tach doesn't work, but does do the full sweep on startup- the IPC engine speed code is there, & my question relates to the white RPM signal wire from PCM, & if the tach sweeps at startup, then where is that signal coming from if the path from PCM is broken? In know all the guages sweep at startup, but all of others work fine. I suspect it's that #10 white wire broken in the wire loom under the battery, probably from the same ancient battery leakage event that ate through the vacuum hose by the frame rail. Just felt it'd wise to get that 2nd or 3rd opinion on this before I contort this old body again to try to get to that rascal... getting to old for crawling under cars!!
