I just adjusted the timing on my 1995 5.7 Silverado. My truck was getting horrible gas mileage and I had already done everything else (i.E. Replaced every damn sensor). The timing was set at around 10 degrees so I set it at 0 (or about as close as I could get it to 0.) This was a pain as every time I tried to tighten that distributor bolt it adjusted the timing slightly. ANYWAYS. When I got the bolt sufficiently tight I checked the timing one last time and then turned the truck off and reconnected the black-tan wire under the firewall (ECT or something?) I drove it around for a bit and rechecked the timing when I got back. I left the black-tan wire plugged in and noticed that my timing was wayyy advanced (probably around 16 degrees) and fluctuating slightly as the RPM's went up and down while idling (This is one of the annoying things I have been trying to fix). So I unplugged the wire and started to re-do the timing adjustment. Well after I unplugged that wire the timing was back to 0 degrees.
So what the heck? When the wire is not plugged in the timing is at 0. When the wire is plugged in the timing reads around 16. Should I leave the wire unplugged? Or is it normal for the timing to jump back up when you plug the wire back in?
have the same problem?
Sunday, March 27th, 2011 AT 11:07 PM