I suspect I may have a malfunctioning (failing?) idle air control valve. Every once in a while (I wish it were more consistent) I start the truck and it immediately dies... unless I hold the accelerator to maintain 1000 to 1500 rpm. Typically, as the engine warms up, the engine operates normally. Only once, the problem occurred with the engine at normal operating temperature. To remove the idle air control valve appears to be a very simple task (Only two screws from an easily accessible location.) I’m sure there’s a proper technique for checking it’s function to determine if it‘s okay, needs cleaned or needs replaced. I’d like to know how to test and if appropriate, clean to restore proper function. If it needs replaced , fine. I just don’t like throwing parts at a problem “just in case”. Especially $140 parts. Any advice would be appreciated.
Jwalker
PCM is Powertrain Control Module. ECM is Engine Control Module. I think the ECM is inside PCM's when they are combined with the Transmission Control Module. 🤷♀️
I have the 5.3L engine 1/2 ton.
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I have the 5.3L engine 1/2 ton.
OpalLacod,
In the section on testing the IAC you gave a range of 12-20 Ohm.
I rechecked continuity again, prior to the following test, and for reasons I cannot explain, instead of 4.3 Ohm I got 45.6 Ohm across the the AB, CD pins. Both outside of the range.
I rigged up some D Cell batteries stepping up from 3 vDC incrementally to 7 1/2 (+/-) vDC. The IAC does nothing.
Can we talk? This thread is turning into a washing machine of prospects.
Some time on the phone may consolidate what I/we know and don't know.
I set up a trash account t2b4ads@gmail.com where you might provide a contact #.
Though based on your last post our understanding may have diverged.
-- "I do have the built-in vacuum line..."
So you are saying your Throttle Body matches the Cardone 67-1075?
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2003 Chevrolet Express 3500 Cargo Van; LQ4 6.0L V8
In the section on testing the IAC you gave a range of 12-20 Ohm.
I rechecked continuity again, prior to the following test, and for reasons I cannot explain, instead of 4.3 Ohm I got 45.6 Ohm across the the AB, CD pins. Both outside of the range.
I rigged up some D Cell batteries stepping up from 3 vDC incrementally to 7 1/2 (+/-) vDC. The IAC does nothing.
Can we talk? This thread is turning into a washing machine of prospects.
Some time on the phone may consolidate what I/we know and don't know.
I set up a trash account t2b4ads@gmail.com where you might provide a contact #.
Though based on your last post our understanding may have diverged.
-- "I do have the built-in vacuum line..."
So you are saying your Throttle Body matches the Cardone 67-1075?
-------------------------------
2003 Chevrolet Express 3500 Cargo Van; LQ4 6.0L V8
For those curious, we took this offline. Will update when resolved.
Right now it looks like the engine was swapped at some point, so we're shooting in the dark a bit more. 🎉
Right now it looks like the engine was swapped at some point, so we're shooting in the dark a bit more. 🎉
Holley 543-34 IAC installed and the idle at warm up has been resolved.
The idle may be smoother but could just be "washed car runs better" syndrome.
I have left the battery connected to see it there is something else that contributed to the dash and starter being dead as a prelude to this exercise.
I will post a full report as a new thread after I see what else may be happening with the van after running it for a while.
The idle may be smoother but could just be "washed car runs better" syndrome.
I have left the battery connected to see it there is something else that contributed to the dash and starter being dead as a prelude to this exercise.
I will post a full report as a new thread after I see what else may be happening with the van after running it for a while.
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