tbb2

Gumby22 - The throttle body is the first one you picture. The IAC is the shiny attachment with the black top on the lower right.

Mine removed:



Something is Off though.
What I am seeing is there are 03 Express 2500 6L V8 IAC valves available.
What is the difference between the 2500 and 3500 that the engine would have a different IAC?

Gumby22

The 2500/3500 is for chassis identification rather than engine. Either chassis could be equipped with a 4.8 or 6.0 depending on intended use.

By the end of 2008, all GM engines were equipped with fully electronic throttle bodies and external IAC’s were no longer in use as that was becoming the industry standard.

Don’t stress too much about the exact year or engine for a replacement - the IAC valves are interchangeable between the engines that use them - as long as the replacement is identical to the existing one, the only thing I’d verify is the O-ring seals correctly (sometimes they’re undersized).

tbb2

Exactly how do I Identify that a replacement is "identical" to the one I pulled out? Especially when the after market vendors all say that their product is not compatible? All I have are the markings on the removed IAC. I have yet to find electrical specifications for any of them, existing or new.

What part am I not to get too stressed about?

What you are telling me makes the most since. I have been speculating that the lack of availability is due to the incorporation of the IAC into the Throttle body Assembly and that being the recommended replacement. How do I determine what other years and engines use the same IAC? Last thing I need is to blow up the 'black box' due to some electrical incompatibility.

I am devolving down to reinstalling the old IAC and just keeping my foot on the gas pedal until the engine warms up.

Gumby22

To clarify -

I said “identical” because the IAC valves from the OBD 1 (late 80’s to late 90’s) days were of a different design than the IAC valves post-2000 but they work exactly the same. Some people get them confused and I was try to help you avoid that.

I can’t tell you why the aftermarket vendors are saying their valves won’t work because I don’t know what information they were looking at - but, you stated your TB looks like the first one I pictured (cable actuated via accelerator pedal), correct?

If so, it doesn’t matter exactly what chassis & engine you look up - the IAC valve is the same. All the GM modular truck/van engines from (approximately) 2000 to 2007 that used an external IAC valve - such as yours - used the same one.

There is no reason to be concerned about burning out the PCM. If something happens at all, it’s because a problem already exists with the PCM or the wiring.

tbb2

I feel like the Caribbean Natives looking at Columbus' ships. Not understanding due to lack of exposure.

Yes I have a cable actuated via accelerator pedal throttle body.
Am I wrong in thinking that any IAC that fits the cable actuated via accelerator pedal throttle body will work as long as it is 2000 or after?
Trying to identify throttle body types by 'plug and chugging' through parts sites is leading me to believe the cable actuated via accelerator pedal throttle body started in 2003. (?)
Should I be thinking the IAC is not specific to the throttle body and be searching for some other compatibility?

I am noticing that the visual appearance of IACs, though similar, the location of the connector does vary. See your pic of Throttle Body.
On the same parts site the IACs for the 2002 & 2003 Chevy Express 2500 6L V8 are the same but there are 7 other options for 2002. One includes a connector splice-in kit.
Below is the IAC for a 2003 Chevy Express 2500 6L V8.
So, if I am understanding you, other than the possibility the connector will not reach to the new location this would work.

Gumby22

(The whole point of forums like this is to ask questions and gain knowledge/understanding, so as long as you’re asking, I’ll do my best to answer.)

[Also, I didn’t realize until just today that you are not the original poster of this thread, so I kept jumping back and forth between your van (2003) and the OP’s van (2006) which was probably affecting my answers. ]

The cable actuated throttle bodies were being phased out - not introduced - in the early 2000’s.

Keep in mind the predecessor to TB’s were carburetors, so the cable connection to the pedal was simply carried over until the fully electronic TB’s replaced them altogether.

The IAC valve you pictured should work and there shouldn’t be any issues with getting the wiring harness to connect either. If there is, you should be able to unwrap the harness and re-route as necessary, but your IAC has a 90* connector and so does the one you pictured, so it shouldn’t be a problem.

tbb2

Yes both connectors come in at 90 degrees to the motor body. But actually the connector for the IAC I removed is about 60 degrees off of the position of the pictured replacement. If I have my orientation correct, the connector instead of facing forward, will face up aligning with the bolt head. This will beg for some better protection from weather dripping off the underside of the engine compartment behind the dash.

Looking back and forth I made these notes:
02 Express 2500 5.7L V8; Throttle Body: NONE LISTED
02 Express 2500 5.7L V8; IAC: United Motor Products, IAC33

03 Express 3500 6L V8; Throttle Body: Dorman, 977-823
03 Express 3500 6L V8; IAC: NONE LISTED

03 Express 2500 6L V8; Throttle Body: Dorman, 977-823
03 Express 2500 6L V8; IAC: United Motor Products, IAC33

04 Express 2500 6L V8; Throttle Body: New design e-Throttle
04 Express 2500 6L V8; IAC: United Motor Products, IAC33 (? no idea how this would fit into the new e-Throttle)

I also came across a Delphi; CV10017 that appearance and size-wise is a match.
Fitment: 2002 Cadillac; Escalade; 6.0L 8 Cyl 5967 cc ... Cadillac; Escalade; "6.0L V8 OHV 16 valves Vortec" ... which is my engine (?)
Delphi tech services like every other supplier is adamant this part is not for the '03 Vortec 6000 6.0L V8 (LQ4) engine.
BUT the part is for the intake air. ??? The only thing that would be off would be how the part operates via the PCM.
This is making me into a conspiracy nut.

Gumby22

There’s always discrepancies between original parts and replacements, whether aftermarket or OEM. This is usually due to design changes that took place after the original parts were installed.

I can’t say anything for certain but it wouldn’t surprise me if the GM replacement has the same connector offset that you’re describing.

Are there any numbers on the original IAC that can be read? If not, PM me the VIN - I should be able to get a current GM part# so you can be sure the replacement IAC is correct.

Also, There shouldn’t be any water getting into the engine bay from around the hood/cowl area - if there is, the cowl needs to be cleaned and/or the hood seals need replaced.

tbb2

The removed IAC was made in Mexico, no manufacturer's name with 2 numbers:
20663
J1702L

I thought I covered this, but the Chevy Dealer Parts Departments informs me there never was a separate part for the IAC and that the Throttle Body w/ IAC and TPS were sold as a unit ... that is now discontinued.

Last 8 of the VIN are: 31110297

Water shouldn't get in but it does and yes the hood gutter could be cleaned more often. There are water marks that indicate it has happened in the past.

Gumby22

I’m guessing the reason GM told you it’s NLA is because it’s common for dealerships to replace a complete assembly as opposed to the individual parts that make it up; so as far as GM is concerned, the whole TB requires replacement as opposed to just the IAC. It’s a ridiculous practice, but quite common in the dealership world.

I need the full VIN - I don’t have any way to look at vehicle info with just the last 8.

Take a look at SMP# AC234 - it looks like a match.