Bad throttle body?

rhoadsrocker · Jul 10, 2017

Hey guys. Was gonna try this "mystical seafoam" in my 05 5.7l and noticed when it was running that the valve in the throttle body doesnt open. Even had my brother in law try hammering the gas for a second and the valve wouldnt budge. It opens easily when you push it so im assuming that it must be a problem with the electronics. Anyone else had this issue? My basic question here is can i just buy a new throttle body here and put it on? Or does it have to be "re-learned" or anything like that before installation?

BigBlue05 · Jul 10, 2017

I'm no expert but It shouldn't have to relearn anything for a throttle body.

rhoadsrocker · Jul 10, 2017

Okay. I wouldn't thint it would either. But ive heard people say it does because that throttle has to be synced to the truck to open and close the valve when the accelerator is applied. But then again. I dont have a ton of knowledge on the throttle system.

charonblk07 · Jul 10, 2017

The TB/PCM do an auto calibration every time the battery is reconnected, you should see the butterfly valve open all the way then return to neutral position the first time it fires up. At idle, the butterfly valve is only open a tiny bit because it has a very low demand for air and in park the butterfly valve opens very little when throttle is applied. If the truck is running/driving fine then there is nothing wrong with the throttle body. Now, is the engine not running at all? or are you worried that when it's idling the butterfly valve is not open?

When adding seafoam it should be done through a vacuum line not through the throttle body, the hose running to the purge canister is a good one to use, don't use the one to the brake booster.

rhoadsrocker · Jul 10, 2017

charonblk07 said:
The TB/PCM do an auto calibration every time the battery is reconnected, you should see the butterfly valve open all the way then return to neutral position the first time it fires up. At idle, the butterfly valve is only open a tiny bit because it has a very low demand for air and in park the butterfly valve opens very little when throttle is applied. If the truck is running/driving fine then there is nothing wrong with the throttle body. Now, is the engine not running at all? or are you worried that when it's idling the butterfly valve is not open?

When adding seafoam it should be done through a vacuum line not through the throttle body, the hose running to the purge canister is a good one to use, don't use the one to the brake booster.

Well it seems like its lagging. I compared it to my brother in laws vehicle with the same motor as mine. When he hammers on the gas (when in park) the valve opens completely on his. When i do it, it doesn't move a single bit

charonblk07 · Jul 10, 2017

rhoadsrocker said:
Well it seems like its lagging. I compared it to my brother in laws vehicle with the same motor as mine. When he hammers on the gas (when in park) the valve opens completely on his. When i do it, it doesn't move a single bit

I'd pull the TB off and have a look at the back side of it. If you haven't cleaned it in a while that is a known issue with the gen III hemi. Even better, if your brother in law is over with his ask him if you could swap TBs and see if it's the TB or your truck.

rhoadsrocker · Jul 10, 2017

charonblk07 said:
I'd pull the TB off and have a look at the back side of it. If you haven't cleaned it in a while that is a known issue with the gen III hemi. Even better, if your brother in law is over with his ask him if you could swap TBs and see if it's the TB or your truck.

Definitely will. So i tried it again. When i hammered on it opened beautifully. When i slowly accelerated it didnt move at all. And when i hammered on it again it only opened 1/4 of the way. Is there any kind of air leak that would cause a lack of a "vaccum affect" on the TB for it to open?

charonblk07 · Jul 10, 2017

rhoadsrocker said:
Definitely will. So i tried it again. When i hammered on it opened beautifully. When i slowly accelerated it didnt move at all. And when i hammered on it again it only opened 1/4 of the way. Is there any kind of air leak that would cause a lack of a "vaccum affect" on the TB for it to open?

I'd pull it first to see how dirty it is, it could be as simple as the amount of torque applied to the butterfly at WOT is able to overcome any dirt restrictions.

rhoadsrocker · Jul 10, 2017

charonblk07 said:
I'd pull it first to see how dirty it is, it could be as simple as the amount of torque applied to the butterfly at WOT is able to overcome any dirt restrictions.

I cleaned it a couple months ago. The thing is practically spottless. It was extremely dirty so i cleaned it. Its gotten just a tiny bit dirty since then but nothing that would restrict movement of the valve.

Bad throttle body?

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