I have to assume my IAC is stuck? When looking at the Log of it sitting and idling, it is stuck on 310 and never moves. Even when I command it to. If the IAC is stuck, how exactly will that affect the drivability and the tune? Any help is greatly appreciated! Attachment 66711
I bet your lean... command more fuel and see what happens
What mods have you done to the car? Is there a hole in the throttle body blade? Also, how clean is your TB? If I were you, I would remove your IAC sensor and look at it. Is it really dirty? Check to see if the plunger is all the way extended or fully retracted. Clean it with some MAF cleaner, put it back in, and do the idle re-learn procedure(google it).
The IAC valve position is referred to as IAC counts. Scan tool data indicating “0” IAC counts means the IAC valve is fully extended (shutting off idle airflow to the engine); and “255” IAC counts means the IAC valve is fully retracted, allowing as much air to enter the engine via the throttle bypass passage as possible. Some ECMs may never allow the IAC to reach 255 counts. Generally, anything you see over 160 counts should be considered to be a near- or fully-open idle air passage.
Now if you see the scan data reporting IAC position higher than 20-50 counts on a fully warmed up engine, this could indicate one or more of the following problems exist:
? There is carbon buildup on the IAC pintle, or in the idle air passage restricting air flow
? There is carbon buildup on the throttle blade or throttle body bore
? The throttle stop screw is adjusted incorrectly (throttle resting closed too much)
? There is a mechanical problem with the engine resulting in lower than expected vacuum levels at idle (this will require the IAC to open further so the engine gets the required amount of air to maintain the preset idle speed)
? There is increased load on the engine (such as what would occur if the automatic transmission was shifted into gear)
? The IAC valve itself is faulty
Any one of the above issues can cause a an IAC fault code to set in the ECM. As you can see, there are many issues other than a faulty IAC valve that can cause a code to set. So before replacing the IAC valve, you should check all of these possible issues first.
I got this from http://www.gmtuners.com/tech/TPS_IAC.htm
1999 Camaro Z28 M6, Forged LS6, Ported LS6 Heads, LS6 BBK Intake, Texas Torquer V3 cam 231/234 .643/.598, Harland Shop Roller Rockers, TSP Hardened Pushrods, Pacesetter Headers, LS7 Lifters, SLP Oil Pump, 3" Exhaust Borla w/cutout, Mahle Pistons w/Hellfire Rings, Forged Eagle Rods, ASP Underdrive Pulley, Rollmaster DBI Timing Chain, LS7 Clutch, BMR Torque Arm/Suspension, 3:73 gears, Pro 5.0 Shifter, ARP 2000 Bolts
I cant look at the log for a vehicle ID but it sounds like it is an electronic throttle body.
I think he should make sure that IAC valve is actually working. If not, replace it.
1999 Camaro Z28 M6, Forged LS6, Ported LS6 Heads, LS6 BBK Intake, Texas Torquer V3 cam 231/234 .643/.598, Harland Shop Roller Rockers, TSP Hardened Pushrods, Pacesetter Headers, LS7 Lifters, SLP Oil Pump, 3" Exhaust Borla w/cutout, Mahle Pistons w/Hellfire Rings, Forged Eagle Rods, ASP Underdrive Pulley, Rollmaster DBI Timing Chain, LS7 Clutch, BMR Torque Arm/Suspension, 3:73 gears, Pro 5.0 Shifter, ARP 2000 Bolts
A 2004 5.3 truck is a DBW and doesn't have an IAC. The 310 IAC value is just a default.
Russ Kemp
Touch?!!!Originally Posted by Russ K
Thank you everyone for the info! Sorry for my ignorance. It is a DBW. I looked on web to see if it did indeed have an IAC and couldn't find anything either way. Once again Thank You All!!
reminds me of when I was 16 working at a parts store and prank calling the other parts sales guys, "I need a thermostat for a 1974 VW" and see how long they poked around in the computer for it.
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