High Idle/Throttle Body Question

[TXRick]

I've read through the forums and have cleaned my MAF, removed and tested my IAC, and did the washer fix but I still have a high idle.

Is the gap supposed to be like this?

I'm thinking about just getting a new tb.
What else could I check?

Thanks Rick

 

[Mynameistommy510]

The gap looks fine to me. What rpm are you idling at? Maybe check pcv valve?

 

[Swede]

Actually, the pics blurry but it looks like it's offset to the right too much and not centered making contact at the 2 o'clock position to me.

 

[HiLife]

Must be the lighting that's making the optical illusion, it does looks off center.

 

[TXRick]

Actually, the pics blurry but it looks like it's offset to the right too much and not centered making contact at the 2 o'clock position to me.

Must be the lighting that's making the optical illusion, it does looks off center.

No optical illusion, that's how it looks. I figure if that is not supposed to look like that then high idle would most likely be a side affect.

I thought maybe I had this guys problem...

High Idle Fixed

but the washer thing did not work for me.

The gap looks fine to me. What rpm are you idling at? Maybe check pcv valve?

Idle is at 1500-1700

I havent changed the PCV, but its really not that old. I'll pick one up today and try it. Cheap and easy anyway.

So, is there a way to fix that gap or am I looking at a new tb?

 

[TXRick]

Another pic...not sure if its any better.

 

[HiLife]

Not saying that this is your issue with your high idle, but, spacing inbetween the butterfly and the tb should be even all the way around.

The throttle body butterfly bolts are staked after assembly at the factory so the bolts don't back out and end up in your engine's cylinder while the engine is turning 2500 rpm's.

Replacing the TB with a better one is a better idea. But, maybe you can very carefully back out (not by force and not all the way out) the bolt just enough the re-center the butterfly, tighten and re-stake the bolts.

I'm wondering how did your TB get that way in the first place? Usually the placement of the butterfly into the TB should last the life of the TB.

 

[TXRick]

Not saying that this is your issue with your high idle, but, spacing inbetween the butterfly and the tb should be even all the way around.

The throttle body butterfly bolts are staked after assembly at the factory so the bolts don't back out and end up in your engine's cylinder while the engine is turning 2500 rpm's.

Replacing the TB with a better one is a better idea. But, maybe you can very carefully back out (not by force and not all the way out) the bolt just enough the re-center the butterfly, tighten and re-stake the bolts.

I'm wondering how did your TB get that way in the first place? Usually the placement of the butterfly into the TB should last the life of the TB.

Wow. Thanks for that bit of info! I figured a new/used one would be the easiest route. The engine was rebuilt about 20,000 miles ago by the previous owner, but I am figuring out that the shop he used probably reused a lot of the parts. So the TB probably has about 270,000+ miles on it....so its lived a long life...and its probably dead.

 

[HiLife]

Is the tb shaft nice with no slop? Or there play in between the tb shaft and the tb shaft hole?

 

[TheDurk]

Is the tb shaft nice with no slop? Or there play in between the tb shaft and the tb shat hole?

You need to use lube on that shat hole.

 

[pluton]

I assume your throttle butterfly is simply not closing all the way??
Based ONLY on my experience with my one current vehicle, the throttle butterfly should be all the way closed at idle. No gap. Certainly no gap that's visible to the human eye. There is a set screw at the REAR of the TB that sets the closed position stop. What else messing with that screw might affect---I have no idea.

My 97 3.4 Fed emissions engine had about a 1100 rpm hot idle when I got it last June. The throttle butterfly just wouldn't close all the way.
I cleaned it and examined in place, but couldn't see any cause.
I had the ream-box, uhh, err, I mean dealer diagnose and fix it.
Their solution: Of course, a new TB. $$$ + $$$
The only nice thing is that a new TB from the dealer comes with a new IAC valve, TPS, and dashpot(s) as well.
When I got the old TB back, it was easy to see that on the rear side of the TB---invisible to me when installed on the vehicle---there is a set screw that controls the resting position of the throttle.
Adjusting that set screw on the old, out-of-car TB seemed to fix the problem of the throttle butterfly not closing all the way. That's all I know.

 

[TheDurk]

I assume your throttle butterfly is simply not closing all the way??
Based ONLY on my experience with my one current vehicle, the throttle butterfly should be all the way closed at idle. No gap. Certainly no gap that's visible to the human eye. There is a set screw at the REAR of the TB that sets the closed position stop. What else messing with that screw might affect---I have no idea.

My 97 3.4 Fed emissions engine had about a 1100 rpm hot idle when I got it last June. The throttle butterfly just wouldn't close all the way.
I cleaned it and examined in place, but couldn't see any cause.
I had the ream-box, uhh, err, I mean dealer diagnose and fix it.
Their solution: Of course, a new TB. $$$ + $$$
The only nice thing is that a new TB from the dealer comes with a new IAC valve, TPS, and dashpot(s) as well.
When I got the old TB back, it was easy to see that on the rear side of the TB---invisible to me when installed on the vehicle---there is a set screw that controls the resting position of the throttle.
Adjusting that set screw on the old, out-of-car TB seemed to fix the problem of the throttle butterfly not closing all the way. That's all I know.

Thing is, an out-of-car 5-speed TB should NOT close all the way. The manual only throttle opener thingy (round drum on front) will only allow full close with vacuum applied. Vacuum hose off that round thingy, it will idle at exactly 1100 RPM and butterfly is cracked open. I know, because it took me six weeks to find out that hose was not pushed on tight. Cured my 1100 RPM high idle instantly and permanently.

 

[TXRick]

You need to use lube on that shat hole.

My girlfriend says thank you. She's waaay more cooperative now

I assume your throttle butterfly is simply not closing all the way??
Based ONLY on my experience with my one current vehicle, the throttle butterfly should be all the way closed at idle. No gap. Certainly no gap that's visible to the human eye. There is a set screw at the REAR of the TB that sets the closed position stop. What else messing with that screw might affect---I have no idea.

My 97 3.4 Fed emissions engine had about a 1100 rpm hot idle when I got it last June. The throttle butterfly just wouldn't close all the way.
I cleaned it and examined in place, but couldn't see any cause.
I had the ream-box, uhh, err, I mean dealer diagnose and fix it.
Their solution: Of course, a new TB. $$$ + $$$
The only nice thing is that a new TB from the dealer comes with a new IAC valve, TPS, and dashpot(s) as well.
When I got the old TB back, it was easy to see that on the rear side of the TB---invisible to me when installed on the vehicle---there is a set screw that controls the resting position of the throttle.
Adjusting that set screw on the old, out-of-car TB seemed to fix the problem of the throttle butterfly not closing all the way. That's all I know.

I've had this thing off three or four times trying to fix it and I noticed that set screw but didn't wanna mess with it because I cleaned the IAC and wanted to eliminate stuff one by one.

Last time I noticed that the set screw was not allowing the blade to close all the way. There are actually two. One on the front stopping the throttle cable holder to a certain point and the other one you are talking about.

I unplugged my battery. Took everything off...again...and readjusted those screws to allow the blade to close further. There is still a small gap but the gap is much smaller. I loosened up the back side and adjusted the front side. Then I snugged up the back side to the new position. It's pretty simple. I used an 8mm socket and a very small Allen wrench to make the adjustments.

I put everything back together and she immediately idled at a lower level. As the computer reprogrammed itself the idle dropped to about 1000. So, immediately a 500-700 rpm decrease.

I'm letting her idle for a few minutes and hoping for more normalization.
I'll post pics and stuff in the morning when I get to a real computer.

 

[TXRick]

These are the two adjusting set screws.

After fix

So, far the idle is between 900-1100. It is still a little high but much much better.

I have to take the TB off again to get to the knock sensors so I'll have another look at it when I do that.

 

[tojo]

Vacuum Hose on TB

where is the placement of the vacuum hose that cracks on the throttle body? Thanks