Dirty Throttle Body do all this?

gunrock

Original poster
Member
Mar 27, 2012
22
Hi Everyone,

Dumb question, I've searched for you tube videos and such, but can't find what I'm looking for. I'm wondering how far the flaps should open on the throttle body when you give it gas.

I've been having a lot of issues. I wonder if some are caused from the throttle body? It looks like it's barely opening?

I noticed when I rev the engine to 3900 RPM's, the throttle body is only opening maybe a third...top flap opens a third or so, the bottom barely--and it almost sounds like a turbo or super charger or something trying to suck in air and the vehicle feels like it lacks power sometimes.

How far should the flaps be opening around 4K? I would think more than "barely".

So my issues may or may not be related to the throttle body and I realize could be a million and one other things too (I am addressing these too), but since I noticed the throttle body and assuming its "sticking', I am wondering if this could be causing the truck to run lean from lack of air? Do you think it would cause the fuel pump to work extra hard to pump more fuel making the pump noisy after operating a while in extreme heat or under load, towing? And assuming a stuck throttle body would make the engine work harder, get hotter?...I have not popped any codes, but again, if it were gradual over time would the computer relearn?

Okay I might be blowing smoke out of my butt and freely admit what I just said might be the stupidest thing you've ever heard, but I am starting to get desperate so I had to turn somewhere as the dealership does nothing (well finds nothing wrong), and I just happened to check my throttle body and noticed it appears to be not opening all the way and wonder if it might contribute to those issues. (to note this is the 3rd fuel pump, same issue, ac delco brand--again for a whole another post)

Thanks,
gunrock
 

Sparky

Member
Dec 4, 2011
12,927
Actually a lean condition is caused by too much air, rich by too much fuel.

I've not looked at my throttle body at various engine RPMs but bear in mind that the position isn't going to be directly related to engine speed. It'll take much less air (and fuel) to hit 4000 RPM without a load on the engine so the throttle body wouldn't have to be too far open. Put a moderate load and it'll need more air and fuel to keep that RPM, so it'll open more. Which by the way in a case like that you'd be pushing the gas pedal more too.

Wouldn't be a bad idea to clean it if you haven't for a long time. Check the O ring seal to be sure it isn't damaged, allowing unmetered air into the engine, and also check vacuum lines.
 

Wooluf1952

Member
Nov 20, 2011
2,663
Milwaukee, Wisconsin
I agree.
If it's never been cleaned now is a good time to clean the t-body and reset the PCM.
However, if you're not getting any codes or having any driving problems, what you are seeing is normal.
 

Mooseman

Moderator
Dec 4, 2011
25,561
Ottawa, ON
I assume that you are looking at the throttle while you're parked and someone is pushing the pedal and revving it. The PCM limits how fast you can rev the engine while in park or neutral so you would never see the throttle open fully. IIRC, it won't let you go past 4000 RPM. Also, stock tuned PCM opens the TB quite slowly as part of the torque management, even when in Drive. This video shows the difference between a tuned PCM and a stock one:
[video=youtube;VLsY7dYjenY]http://www.youtube.com/watch?v=VLsY7dYjenY[/video]

As the others have mentioned, you should clean your throttle body to start. And depending on mileage, it might also be time to change your plugs. Use only ACDelco 41-103 plugs. What are the symptoms exactly?
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
You've been answered well so far. No load takes very little fuel and air to spin up the engine.

Problems of low power when under load can be a clogged cat, so somebody should run an exhaust backpressure test.

I'm more curious about your description of "flaps" in the throttle body. There is one round disk on a pivot axle. Surely you're not seeing the two edges of the disk open different amounts, which would imply a bent disk.
 

gunrock

Original poster
Member
Mar 27, 2012
22
Hi everyone,

Thanks for the replies...that answers my question--funny I did watch the youtube video Mooseman posted earlier before I posted this thread. :smile:

As far as the "bent flaps" I think it was an optical illusion--it is fine...especially after taking apart the throttle body and seeing how it works....

I ended up cleaning the K&N filter with their kit--it was DIRTY and I took apart the throttle body to clean it--I will finish it tommorow....it's pretty gummed up.--last time I cleaned the TB was around 100K when I did the plugs...so it's been 50K miles--I can hope for a more smooth idle.

Also, the gasket is fine.

Honestly, as far as the power loss, I'm not sure it's a problem...I could be imagining it...I did do a simple test to see if it would hit the 6200 rpm 1-2 shift point? (think I found that here) and it seemed okay.

Thank you for sharing your expertise! :thumbsup:

gunrock


d09d0ae3.jpg

37093ffa.jpg
 

gunrock

Original poster
Member
Mar 27, 2012
22
Just following up ...man, idle is smooth now and when I give it gas in park (to the max RPM's) it no longer acts like its going to stall....

One more thing off the "to do" list.

Thanks :thumbsup:
 

Delor

Member
Jul 11, 2012
12
gunrock said:
Just following up ...man, idle is smooth now and when I give it gas in park (to the max RPM's) it no longer acts like its going to stall....

One more thing off the "to do" list.

Thanks :thumbsup:

Just curious what exactly you did to end up relieving your issue? Clean TB and airfilter? Was that all?
 

gunrock

Original poster
Member
Mar 27, 2012
22
Delor said:
Just curious what exactly you did to end up relieving your issue? Clean TB and airfilter? Was that all?

Well my original post about the the overheating and noisy fuel pump still exist and I am addressing those, so no, but I as far as the rough idle and acting like it was going to stall---yup the TB cleaning sure fixed that issue. I also ended up cleaning the K&N filter with their kit and applying the oil.

I really have not noticed any increase in MPG though. My driving is too varied and the area I am in with the hills and such, I'm lucky to get 16 mpg. I have the 3.73 rear end for reference.

Now I've also just read about the warning against disconnecting battery and the bad things that can happen, so it's probably a good thing I cleaned the throttle body and counting my lucky stars that all the hvac blowers work. :smile:

gunrock
 

eB@WLZ

Member
Apr 29, 2012
4
So watching that video just got me thinking about a PCM tune. Does anyone know if those parameters....sounded totally greek to me...woudl match with what PCM for Less programs?
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
gunrock said:
Now I've also just read about the warning against disconnecting battery and the bad things that can happen, so it's probably a good thing I cleaned the throttle body and counting my lucky stars that all the hvac blowers work.
My attitude is that if a battery disconnection or accidental discharge kills a weak actuator, it deserved to die and get replaced anyway while you have your tools out. You don't want to kill an actuator in extreme heat conditions or while far from home on a trip, when you can't control the timing of a battery problem.

It's like living with a slightly-annoying roommate, hoping they'll get better on their own and not snap and kill you in your sleep someday.
 

gunrock

Original poster
Member
Mar 27, 2012
22
the roadie said:
My attitude is that if a battery disconnection or accidental discharge kills a weak actuator, it deserved to die and get replaced anyway while you have your tools out. You don't want to kill an actuator in extreme heat conditions or while far from home on a trip, when you can't control the timing of a battery problem.

It's like living with a slightly-annoying roommate, hoping they'll get better on their own and not snap and kill you in your sleep someday.

LOL true, nice anaology, I probably wouldn't care so much, but I've been dropping a ton of money in repairs on my truck the last couple of months...it just needs to give me a break so I can catch up on my bills. :crazy:
 

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