Quick question about the IAC valve

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Burban1990

Full Access Member
Joined
Nov 25, 2018
Posts
313
Reaction score
285
Location
Vancouver, Wa
First Name
James
Truck Year
1990
Truck Model
Suburban 2500
Engine Size
350
I'm going to replace my IAC valve with an AC Delco is there anything I need to know when putting in the new one other than resetting the IAC for during normal procedures?
 

AuroraGirl

Full Access Member
Joined
Sep 8, 2019
Posts
9,242
Reaction score
6,232
Location
Northern Wisconsin
First Name
Taylor
Truck Year
1978, 1980
Truck Model
K10, K25
Engine Size
400(?), 350
Do NOT push or pull the pintle. if you ever must depress it manually, turn it in so you dont damage worm gear. Make sure to use a good o ring
 

Burban1990

Full Access Member
Joined
Nov 25, 2018
Posts
313
Reaction score
285
Location
Vancouver, Wa
First Name
James
Truck Year
1990
Truck Model
Suburban 2500
Engine Size
350
So I've read about relearning for the IAC.
If someone with this experience could help. I just need to know about order of things I'm a little unsure. If I'm correct I believe I replace IAC then reset the idle and then afterwards relearn the throttle body in this order? I apologize for my ignorance I'm kind of new to throttle body. The last four square bodies I've owned have all been carbureted from the 70s. Also please inform me if I'm just overthinking it.

https://itstillruns.com/reset-baseline-idle-gm-tbi-7959677.html

https://ricksfreeautorepairadvice.com/gm-throttle-body-relearn-procedure/
 
Last edited:

Burban1990

Full Access Member
Joined
Nov 25, 2018
Posts
313
Reaction score
285
Location
Vancouver, Wa
First Name
James
Truck Year
1990
Truck Model
Suburban 2500
Engine Size
350
Do NOT push or pull the pintle. if you ever must depress it manually, turn it in so you dont damage worm gear. Make sure to use a good o ring

I read to manually push in the pintle if it's sticking out too far before you install it. "Turn it in" could you please elaborat?
 

AuroraGirl

Full Access Member
Joined
Sep 8, 2019
Posts
9,242
Reaction score
6,232
Location
Northern Wisconsin
First Name
Taylor
Truck Year
1978, 1980
Truck Model
K10, K25
Engine Size
400(?), 350
You must be registered for see images attach

that is your valve yes? when its too far out, you want to twist... uh.. counter? i think when applied it clockwise extends, but when its retracted its counter or at least opposite. If you push it in it could damage the threads.
 

AuroraGirl

Full Access Member
Joined
Sep 8, 2019
Posts
9,242
Reaction score
6,232
Location
Northern Wisconsin
First Name
Taylor
Truck Year
1978, 1980
Truck Model
K10, K25
Engine Size
400(?), 350
So I've read about relearning for the IAC.
If someone with this experience could help. I just need to know about order of things I'm a little unsure. If I'm correct I believe I replace IAC then reset the idle and then afterwards relearn the throttle body in this order? I apologize for my ignorance I'm kind of new to throttle body. The last four square bodies I've owned have all been carbureted from the 70s. Also please inform me if I'm just overthinking it.

https://itstillruns.com/reset-baseline-idle-gm-tbi-7959677.html

https://ricksfreeautorepairadvice.com/gm-throttle-body-relearn-procedure/
the 2nd one is for newer than tbi. like 2005+. the first one should be ok
 

AuroraGirl

Full Access Member
Joined
Sep 8, 2019
Posts
9,242
Reaction score
6,232
Location
Northern Wisconsin
First Name
Taylor
Truck Year
1978, 1980
Truck Model
K10, K25
Engine Size
400(?), 350
Also what makes you think you need a new IAC? It probably just needs to be cleaned if you have EGR
 

Burban1990

Full Access Member
Joined
Nov 25, 2018
Posts
313
Reaction score
285
Location
Vancouver, Wa
First Name
James
Truck Year
1990
Truck Model
Suburban 2500
Engine Size
350
Also what makes you think you need a new IAC? It probably just needs to be cleaned if you have EGR

I had a constant high idle and had to replace the coolant temperature sensor. After doing so the idle has gone back down to factory setting and the problem was fixed and it ran perfect. About a week and a half later I noticed the idle started surging and going up and down. I also replaced all vacuum hoses just cuz I found a few that were cracked. Last night I thought I would reset the idle to see if that would help to no avail. Then I started it up let it run for a few minutes to get warm unplugged the IAC and it ran perfectly fine as soon as I plug the IAC back in the idle started to surge up and down and then actually died. Over the last couple of days I had just noticed the fluctuation in the idol was getting worse.
 

Burban1990

Full Access Member
Joined
Nov 25, 2018
Posts
313
Reaction score
285
Location
Vancouver, Wa
First Name
James
Truck Year
1990
Truck Model
Suburban 2500
Engine Size
350
And please correct me if I'm wrong but the spintle shouldn't be any further out than 26 mm?
 

AuroraGirl

Full Access Member
Joined
Sep 8, 2019
Posts
9,242
Reaction score
6,232
Location
Northern Wisconsin
First Name
Taylor
Truck Year
1978, 1980
Truck Model
K10, K25
Engine Size
400(?), 350
Im not sure. my engines all relearn IAC on their own. I would turn it in mostly seated and try that
 

Burban1990

Full Access Member
Joined
Nov 25, 2018
Posts
313
Reaction score
285
Location
Vancouver, Wa
First Name
James
Truck Year
1990
Truck Model
Suburban 2500
Engine Size
350
Turns out the IAC that was in it was an AC Delco. Wasn't gummed up or anything actually look pretty clean. Just went bad I guess! The throttle body was rebuilt not too long ago but either way I'm glad it's happy.
 

AuroraGirl

Full Access Member
Joined
Sep 8, 2019
Posts
9,242
Reaction score
6,232
Location
Northern Wisconsin
First Name
Taylor
Truck Year
1978, 1980
Truck Model
K10, K25
Engine Size
400(?), 350
Turns out the IAC that was in it was an AC Delco. Wasn't gummed up or anything actually look pretty clean. Just went bad I guess! The throttle body was rebuilt not too long ago but either way I'm glad it's happy.
so its fixed?
 

Forum statistics

Threads
42,235
Posts
911,865
Members
33,737
Latest member
calebrwalk5
Top