[rfmaster]

Originally Posted by cyberpine

So I just changed the IAC value. No real difference and I still don't see the pinnacle coming through. Truck stalls and heavy smoke and gas smell. I also hear that IAC motor trying to do something with a constant slgiht buzz with the key on start and and ECM A&B shorted.

I have not checked my timing or my RPMs at idle.

Here's the thing thing though, as before, when I disconnect the MAP sensor and that temp sensor it idles a little high, but it runs incredibly strong. I would say there is no way it could run like that if my timing was terribly off.

You may have answered this (need to go back), what's the worse that could happen from running the truck this way (with those sensors disconnected).. high fuel consumption? overheating at idle?

Remembering something the first mechanic told me.. he said he tried to get the timing on the truck but could not explaining the constant fluctuation I'm seeing with the sensors on.

Thanks.

JC

TBI system was designed to use all sensors (TPS, CTS, MAP, VSS, KS, EST) and actuators (IAC, EGRCV, Injectors) for normal operation. Disconnecting them puts ECM in soft fail mode where it reverts to fixed value for a disconnected sensor - enough to get you pull over and limp over to a service bay. Disconnecting and otherwise rendering sensors inoperative will not get this problem resolved. Drivability and performance are compromised.

IAC appears to be functioning. I went to my local parts store and pulled a new TBI replacement IAC and compared to OE GM. OE unit tends to have longer - conical head. This would explain why I can see it from the top. I'll have to assume that it is functioning based on you report - it is clicking and that's what it suppose to do in diagnostic ALDL mode (A+B).

Timing - You must check and set correct timing. It is a very common mistake to incorrectly set timing on TBI systems with end results similar to yours.


How's bidding on Evil Bay?
//RF