Tweet
After replacing the camshaft in my 85 it has developed a strange problem that has us puzzled. It runs fine until the temperature reaches about 175 degrees and then the idle goes to 1700 and remains there until you turn it off. Upon restart it will return to normal idle until the temperature comes up again. The shop manual identifies the IAC valve as the culprit but replacement of both that component and the ECM has failed to correct the problem. Anyone have any experience with this problem? Thanks.
-
-
Re: 85 idle
It sounds like you are having a problem with temperature sensing. I would sugggest checking the inputs from the sensors to the computer at the temp where the problem occurs, Even if it has to run at 1700 for a few moments, it won't hurt anything, and you should be able to identify the problem. First thoughts would be either a sensor was damaged, a connection not made properly, or a wire pinched in the course of the camshaft change. I think that is about the temp where the ECM shifts from open loop control to closed loop control.Bill Clupper #618 -
Re: 85 idle
Thanks Bill. Since we recently changed the ECM we are going to start with those conncections and the wiring to the sensors. Appreciate the information.Comment
-
Re: 85 idle
If you can get ahold of a scanner, it will allow you to hoop up to the aldl port under the dash and compare the information being fed into the computer with the expected values which are listed in the service manual. That is probably the easiest way to look for what input(s) are out of sync and thus narrow the field of places to look.Bill Clupper #618Comment
Comment