IAC?

[01DenaliHiker]

So I have a 2001 GMC Denali with the 6.0 LQ4.

After going through a heck of a fun time putting speed engineering shortys on it today and freaking out thinking my truck was breaking down because I'm a scatterbrained ninny who doesn't put O2 sensors back where they belong a fun red number popped up when I was running the snap on computer on it for live data.

It showed I had a bad IAC? My TB is electronic, I thought only cable driven TBs had IACs. Plus, I was on a witch Hunt and saw nothing that resembled one anywhere around my throttle body.

So my question is, is there an invisible IAC somewhere on my engine that I'm just not seeing? That the snap on computer is somehow pulling a bad signal from? I do have a funky idle from time to time, but nothing that would make me think it was a bad IAC, with my luck it's just a vacuum leak somewhere I haven't smoked out yet.

My throttle body has a TPS on the driver's side and the elongated electronic throttle control (?) deal on the passenger side.

 

[Rocket Man]

I believe the "elongated electronic throttle control" on the passenger side is the IAC. It should look like this. Also, I'm pretty sure 2002 was the first year for electronic throttle control. I know when I was buying my Whipple blower, BlackBear had me check to see if my 02 had electronic throttle because supposedly they came into the LQ4's midway through 02. It consists of a computer in a box mounted to the firewall near the brake booster and the pedal with wires attached that connect to the box. The box connects to the TB through a wiring harness.

 

[01DenaliHiker]

I believe the "elongated electronic throttle control" on the passenger side is the IAC. It should look like this. Also, I'm pretty sure 2002 was the first year for electronic throttle control. I know when I was buying my Whipple blower, BlackBear had me check to see if my 02 had electronic throttle because supposedly they came into the LQ4's midway through 02. It consists of a computer in a box mounted to the firewall near the brake booster and the pedal with wires attached that connect to the box. The box connects to the TB through a wiring harness.

Only issue I have with the elongated part, is there's no pigtail ran to it, dang sure doesn't look like an IAC. I stared at pictures of that all day wondering where that exact part was. Unless it's just a casing. Lol. Unless my throttle cable is ghosting me too, it's nowhere to be found. Only reason I assumed I was electronic.

 

[01DenaliHiker]

https://www.rockauto.com/en/catalog/gmc,2001,yukon,6.0l+v8,1420524,fuel+&+air,throttle+body,6472

That's my throttle body.

 

[Doubeleive]

So I have a 2001 GMC Denali with the 6.0 LQ4.

After going through a heck of a fun time putting speed engineering shortys on it today and freaking out thinking my truck was breaking down because I'm a scatterbrained ninny who doesn't put O2 sensors back where they belong a fun red number popped up when I was running the snap on computer on it for live data.

It showed I had a bad IAC? My TB is electronic, I thought only cable driven TBs had IACs. Plus, I was on a witch Hunt and saw nothing that resembled one anywhere around my throttle body.

So my question is, is there an invisible IAC somewhere on my engine that I'm just not seeing? That the snap on computer is somehow pulling a bad signal from? I do have a funky idle from time to time, but nothing that would make me think it was a bad IAC, with my luck it's just a vacuum leak somewhere I haven't smoked out yet.

My throttle body has a TPS on the driver's side and the elongated electronic throttle control (?) deal on the passenger side.

Must be a Denali thing I thought all the 00-02 had a throttle cable, at an rate the iac is internal to the throttle body on the electronic ones and I believe you have to replace the entire control or just get a another complete throttle body, looks like yours has that weird coolant connector on it.

 

[Rocket Man]

That's the same TB as mine and it's definitely electronic. Are you sure it's not pointing to a bad IAT sensor? What's the code?

 

[01DenaliHiker]

That's the same TB as mine and it's definitely electronic. Are you sure it's not pointing to a bad IAT sensor? What's the code?

No codes at all as far as that goes. Live data showed 320 counts with the specified of 250 max. Just caught me weird because that computer usually doesn't pull something that's not there, will just show no value.

 

[01DenaliHiker]

Must be a Denali thing I thought all the 00-02 had a throttle cable, at an rate the iac is internal to the throttle body on the electronic ones and I believe you have to replace the entire control or just get a another complete throttle body, looks like yours has that weird coolant connector on it.

It must be, that coolant connector is bypassed do to some super fun uninformed routing from who I bought it from. Was an adventure all in itself.

 

[Rocket Man]

It must be, that coolant connector is bypassed do to some super fun uninformed routing from who I bought it from. Was an adventure all in itself.

Ahh, the infamous TB coolant bypass mod. never knew why GM decided to run coolant through the TB anyway but that mod can sometimes cause confusion and there's no gain to be had. As far as the IAC , my motto is if there's no codes there's no problem. Get back to those headers lol.

 

[01DenaliHiker]

That's the same TB as mine and it's definitely electronic. Are you sure it's not pointing to a bad IAT sensor? What's the code?

Ahh, the infamous TB coolant bypass mod. never knew why GM decided to run coolant through the TB anyway but that mod can sometimes cause confusion and there's no gain to be had. As far as the IAC , my motto is if there's no codes there's no problem. Get back to those headers lol.

I dig that motto. Hahaha. Headers are on. Surprisingly with dual flowmaster ten series and those headers it sounds amazing and there's such a minimal amount of drone I can drown it out with my radio at two on the volume. Super pleased, minus the hell of a flange that didn't match the actual exhaust pipe, that was fun.

At least that bypass is run correctly now, instead of dumping coolant into my passenger valve cover. It's been fun finding all the craziness fixing this thing back up. Lol. Should've seen all the bare wire redoing the system, it was truly amazing the truck never burnt to the ground.