Today's fun. Unplugged the IAC and drove it man was it fun ran like a top. Shifted good ran good and everything did fin got it home plugged in the IAC bang right to 2000.
Today's fun. Unplugged the IAC and drove it man was it fun ran like a top. Shifted good ran good and everything did fin got it home plugged in the IAC bang right to 2000.
Who needs an Iac anyways. IM glad you got to enjoy it finally even thoughu havent found your problem it gives you a reason to keep looking for it.
2000 Silverado ECSB- 5.3 CAI, Pacesetter LTs, ORY- Pipe, Magnaflow XL, E-fan, Ported T/B , Nelson Tuned, Built 4l60e, Circle D Stall, 3.42s G80, 2-4 Drop, Hertz Highs, Rockford 501s
2004 Buell XB12s
Originally Posted by LamboDoNoMo
Thanks a lot. I hope to find out what is going on first of the week. Man it was fun to finely get to drive it.
OK Put on a loner TB today same thing. Unplugged idle is fine plugged in and it jumps to 2000.
I would get a totally stock pcm from another truck and swap it in and see what happens. May have to swap in stock injectors to avoid any problems there. Just leave the trans unplugged too. This would hopefully be able to help you rule out the pcm as being the problem.
Have you tried driving it with the idle at 2000rpm?
Big slow mud truck with a TUNE!!!!!!
No have not.
Ya, that's the next step.
We're gonna try a stock pcm with the right trans settings, and stock tune.
We're gonna use his vin and the 80e setup.
I know for a fact it's not my calibration, but that doesn't mean the calibration isn't messed up somewhere I can't detect.
The idle tables are 100% stock on all the pcms, but that still doesn't mean something is screwy somewhere in the pcm.
this is definitely a weird one.
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You calling me weird?? I am ready to try something. THANKS
What about this
The purpose of the IAC valve is to control engine idle speed, while preventing stalls due to changes in engine load. The IAC valve, mounted in the throttle body, controls a portion of the bypass air. An orifice located between the throttle valves also supplies a constant amount of bypass air. By moving a conical valve known as a pintle (3) in toward the seat, to decrease air flow, or out away from the seat, to increase air flow, a controlled amount of air can be bypassed. If engine speed is too low, more air is bypassed in order to increase RPM. If engine speed is too high, less air is bypassed in order to decrease RPM. The PCM moves the IAC valve in small steps, called counts. These can be measured and displayed with a scan tool, which plugs into the data link connector (DLC). The PCM calculates the proper position of the IAC valve during idle based upon the battery voltage, the coolant temperature, the engine load, and the engine RPM. If the RPM drops below specification and the throttle valve is closed, the PCM senses a near stall condition and calculates a new valve position in order to prevent stalling.
* Engine idle speed is a function of total air flow into the engine. Idle speed is based on IAC valve pintle position, crankcase ventilation valve flow, throttle valve opening, bypass orifice air flow, and calibrated vacuum loss through accessories.
* Controlled idle speed is programmed into the PCM, which determines the correct IAC valve pintle position to maintain the desired idle speed for all engine operating conditions and loads.
* The minimum idle air rate is set at the factory with a stop screw. This setting allows enough air flow by the throttle valves to cause the IAC valve pintle to be positioned a calibrated number of steps, counts, from the seat, during controlled idle operation.
* If the IAC valve is disconnected and reconnected with the engine running, the idle speed may be wrong. If this occurs, reset the IAC valve by depressing the accelerator pedal slightly, starting and running the engine for 5 seconds, and then turning the ignition OFF for 10 seconds.
Well that was a bust no help at all.
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