Any mechanics that can help...high idle

[cvgunman]

I have a 2000 Chevy Silverado 1500 5.3 vortec.

Here's my issue:
Last week I replaced the intake manifold and while I had it off, cleaned the throttle body which had over 500k of carbon built up. Everything went back together smooth, but now I have an issue with the idle. When starting cold in the morning, it will idle between 2000-2500 rpm. This is not good. The idle will not come down at all. When I put it in drive, the truck will lurch forward, also not good, and then i can drive the truck and after a few miles, the idle will come down some. I have checked and cannot find a vacuum leak, but have read where the ECM may need to "re-learn"? I took it for a long rive today hoping the ECM would "learn" something, but nothing.
Any advice (besides buy a Ford)

 

[RedArmy]

I have a 2000 Chevy Silverado 1500 5.3 vortec.

Here's my issue:
Last week I replaced the intake manifold and while I had it off, cleaned the throttle body which had over 500k of carbon built up. Everything went back together smooth, but now I have an issue with the idle. When starting cold in the morning, it will idle between 2000-2500 rpm. This is not good. The idle will not come down at all. When I put it in drive, the truck will lurch forward, also not good, and then i can drive the truck and after a few miles, the idle will come down some. I have checked and cannot find a vacuum leak, but have read where the ECM may need to "re-learn"? I took it for a long rive today hoping the ECM would "learn" something, but nothing.
Any advice (besides buy a Ford)

Throttle position sensor could be the culprit. Check the throttle blade is not hanging in the throttle body as well, check the two screws. Also make sure the contacts and wiring to the throttle body censor are not full of gunk or damaged. No to be the bringer of bad news but, I can't count the times people have cleaned a throttle body and the sensor ends up needing to be replaced afterward. I'm not sure of the setup on a Vortec but the LS3 throttle body sensor is very sensitive to having it's blade being moved around by hand and can be damaged easily.

 

[RedArmy]

I think you have to remove the alternator on those old Vortecs to get to the sensor if I'm not mistaken. Might not be the case for all of them.

 

[Vaquero]

Damned censors.

 

[RedArmy]

Damned censors.

Done censored myself.

 

[ZX9RCAM]

500k miles, damn!

 

[RedArmy]

No codes present at all?

 

[cvgunman]

I kept reading about the throttle position sensor, so to be on the safe side I replaced it. The idle went up higher.

 

[cvgunman]

No codes present at all?

I'm guessing that should be my next step. I do not have a code reader, and am hesitant to drive it, not that it doesn't run, I just don't want to f-up the transmission or something else when it slams into gear t high idle.

 

[RedArmy]

I kept reading about the throttle position sensor, so to be on the safe side I replaced it. The idle went up higher.

Strange, you sure the gaskets not leaking around the throttle body?

 

[RedArmy]

Did a quick check at my usual grease monkey hangouts and found that your throttle body will need to relearn by scan tool.

This is what you need:

FIXED!!!! My neighbor had a Snap On Solus Ultra scanner, hooked it up and it has an idle relearn option, took about 5 seconds and all is right in the universe!!!

 

[cvgunman]

Strange, you sure the gaskets not leaking around the throttle body?

New gasket torqued to 89in/lb no leaks. From what I can tell, there are only 3 vacuum lines and none are cracked and no leaks.

 

[cvgunman]

Did a quick check at my usual grease monkey hangouts and found that your throttle body will need to relearn by scan tool.

This is what you need:

FIXED!!!! My neighbor had a Snap On Solus Ultra scanner, hooked it up and it has an idle relearn option, took about 5 seconds and all is right in the universe!!!

Does neighbor still have and how much to scan/reset?

 

[RedArmy]

Does neighbor still have and how much to scan/reset?

I only looked up the procedure so unfortunately you'll need to have this done by a shop. That particular scan tool is very expensive. I no longer have access to pro shop tools since I'm an IT guy now. Try calling around to see if any local shops can do the job, try to avoid the Chevy steelerships.

 

[cvgunman]

I only looked up the procedure so unfortunately you'll need to have this done by a shop. That particular scan tool is very expensive. I no longer have access to pro shop tools since I'm an IT guy now. Try calling around to see if any local shops can do the job, try to avoid the Chevy steelerships.

10-4
Thanks for the heads up.
The ONLY thing I miss about CA (besides my family) is my mechanic. Have to find/establish new relationship here.

 

[Axxe55]

CV, you might try this procedure. Not for sure it applies to your year and application, but might be worth a try.

https://www.rockauto.com/genImages/22/BOU-AVM-1-I-080B.pdf

 

[RedArmy]

I don't think that will work but worth a try, most of those old ECM's don't have the learning features of the newer ones.

 

[Axxe55]

I cleaned my TB now high revs @ idle - Chevrolet Forum - Chevy Enthusiasts Forums

Tahoe & Suburban - I cleaned my TB now high revs @ idle - 2007 5.3 Felxfuel I cleaned my throttle body, now I have high RPM at idle around 2000. I disconnected the battery for 10 mins. That did not do it I have only driven about 50 miles since which was ony 2 starts 25 miles each way. Every...

chevroletforum.com

 

[cvgunman]

CV, you might try this procedure. Not for sure it applies to your year and application, but might be worth a try.

https://www.rockauto.com/genImages/22/BOU-AVM-1-I-080B.pdf

I gave this a go today. Drove up to Sherman and back. Seemed like it might have learnt something, but after a stop at Buccee's, hello high idle. Going to look around tomorrow for someone with the can tool to reset throttle and idle.

ETA: I also saw one claim of disconnecting the battery, pump brakes 3 times and connect battery problem solved. Well I would have had as much luck with clicking my heels three times and showing up in Kansas.

 

[Axxe55]

I gave this a go today. Drove up to Sherman and back. Seemed like it might have learnt something, but after a stop at Buccee's, hello high idle. Going to look around tomorrow for someone with the can tool to reset throttle and idle.

You might try the reset of the ECM, by disconnecting the negative battery cable for about fifteen seconds. It might relearn it that way.

If none of that works, it might mean a trip to a GM dealership that has a Tech 2 scan tool to do the reset.