MikeE024

TJ Addict
Supporting Member
Joined
Mar 29, 2021
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Tucson
I did a boost leak test using soapy water and found both ends of the TB shaft leaking. No other leaks at the TB.

Is there a seal and/or bearing for each end of the shaft that I can order? Or is there a TB rebuilder that anyone would recommend I contact?

I appreciate the help on this.
 
I think I remember someone buying bushings to replace inside a TB but I don't recall details. Replacing the entire throttle body might be easier. How much is it leaking? You'd be surprised how much is a leak won't affect (boosted) performance in the least. Now is it's causing a vacuum leak issue off boost, that could be a bigger deal.
 
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I think I remember someone buying bushings to replace inside a TB but I don't recall details. Replacing the entire throttle body might be easier. How much is it leaking? You'd be surprised how much is a leak won't affect (boosted) performance in the least. Now is it's causing a vacuum leak issue off boost, that could be a bigger deal.

I've had an intermittent rough idle and poor gas mileage for most of my time owning the rig. I recently found an exhaust leak near the gasket.

I can't say for certain if the throttle body has been a major contributor to these issues, but I have it feeling it does not after reading your post. The system hisses pretty bad under boost and the only leaks I found were at the TB. However, I was so concerned with my turbo to manifold plumbing that I failed to soapy water test the vacuum lines that come off the manifold. It's possible that one of my vacuum hoses or connection points are leaking. I'll check this.

The system popped codes saying it detected a lean condition. I thought I solved the issue but the codes came back about two weeks later. I had to put the Jeep in storage and leave the state, so I'm stuck in plan phase until the end of May.

I received a used oem TB from ebay yesterday. I'll throw that in after I replace my exhaust manifold and check for other potential vacuum/boost leaks off the manifold.

Until reading your post, I assumed the TB leak might be critical to achieving boost, so I appreciate you sharing your wisdom on this (I'm a newb to this boost stuff).
 

Guy shows how he repairs them with some new o rings. Might be something to get you sealed up. Looks simple enough. I have never taken a throttle body apart but I guess the Cherokee 4.0 is the same as the TJ in this case.
 
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Guy shows how he repairs them with some new o rings. Might be something to get you sealed up. Looks simple enough. I have never taken a throttle body apart but I guess the Cherokee 4.0 is the same as the TJ in this case.

Thanks man, I saw the video in this post after searching "bushing TB Wrangler TJ forum" after Skyline's post. I was stoked on Rusty's workaround. Pretty neat!

For anyone viewing the video in the future, Rusty's video is awesome, but his mention of the o-ring size being "012" is not the measurement of the o-ring. It was actually the label of the o-ring location his HF metric o-ring kit. No exact details on which rubber it was, but the details I mentioned are deep in the comments of the video.

I don't have a single tool in my tiny NYC apartment since I'm only here for training. But, I may get a screwdriver and bits to crack off the TPS of my ebay purchase so I can see if the '05 TB shaft bearing looks similar to the '99 xj shaft bearings in the video. Fingers crossed and thanks again for trying to help me out @kincaid.0678 and @SkylinesSuck
 
Just keep in mind I'm not saying don't fix leaks. It's just not going to have a noticable impact on spool times or power or anything. It certainly could fix a whistle though.

If you look at the amount of air the turbo is pushing say boost compared to the tiny amount a small leak can flow, it's miniscule. The turbo just says "meh, here's a little more air to make up for it" and continues on its merry way.
 
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I just saw where you said you had a CEL for running lean. What are you using for tuning?

The whistle was there when I bought the Jeep. The first time I noticed a lean code was during the summer right after the transmission was swapped, which seemed like odd timing. I had an FRP stock tune at that time.

I swapped out an O2 during winter break and the code went away so I did the turbo install, but then it came back. The tune is currently from Banks for their turbo.

I have a feeling that changing the exhaust manifold will solve the lean code and help with spool since I have at least one leak there. It would still be nice to solve the ever-present whistle and the pronounced hiss that I hear under boost.

I don’t have any misfire codes fwiw, just lean codes and awful gas mileage that I first noticed during my drive from CA to AZ before changing the b2s2 and doing the turbo. And no overheat coolant temps of any sort before or after the turbo (I assume this is bc the fuel being dumped kept things cool).
 
I believe I read that the TBs are the same but I’m not sure. I’ll happily buy the bearings to find out and will update the thread later with the results. Thanks!

Dimensions for the bearings are an online. Might make a quick check first.
Nor do I know how difficult removing old bearings will be.
 
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Dimensions for the bearings are an online. Might make a quick check first.
Nor do I know how difficult removing old bearings will be.

The YouTube video posted by @kincaid.0678 above makes it look like the bearings are easy to remove, but I’m not sure if my 05 tb bearings will move that easily. I’ll find out when I get back to the rig.
 
Any thoughts to having Ryan (FRP) redo the tune? After fixing the exhaust leak of course.

What are you using to do a boost leak check?
 
Any thoughts to having Ryan (FRP) redo the tune? After fixing the exhaust leak of course.

What are you using to do a boost leak check?

I have an HP Tuners and let Ryan know that I might have him do a tune. My biggest issue with wanting to do more was that I simply ran out of time.

With that said, I’d prefer to have Ryan do the tune once I get the intercooler set up installed and thought it would be wise to have the tune written based on how the system runs during the desert summer so I know it’s safe for those conditions. Feel free to critique my line of thought if it’s flawed.

Trying to plan ahead at this point and figured it would make sense to solve the exhaust manifold leak, vacuum/boost leaks, open up the post-turbo exhaust plumbing, install intercooler, then look at a potential re-tune.

For boost leaks, I used a kit from Amazon. I didn’t love it bc I had depth issues since the pucks are stepped with different sizes. They just barely fit and were annoying to fight with imo. I’d rather have dedicated puck sizes.
 
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Update:

I did a pressurized smoke test to my intake side. Both ends of my original TB’s butterfly valve poured out smoke out (I knew it was leaking from the hiss and the previous soapy water, the the smoke really showed how massive the leak was).

I cleaned up my eBay throttle body and took it for a spin. The rig goes into boost much easier now. The system seems to run smoother but that could just my perception.
 
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Having the same issue with the valve shaft leaking, did swapping the TB fix your problem? Has anyone done the O-ring mod like the video shows?
 
Having the same issue with the valve shaft leaking, did swapping the TB fix your problem? Has anyone done the O-ring mod like the video shows?

The eBay TB didn’t fix it. I did a boost leak test two days ago that confirmed the TB leak is the reason I’m still not making sufficient boost unless I really get on the throttle. I ran 5 psi to the intake system through the test kit, yet the test gauge read 0 psi.



I have plans for the original TB and eBay TB now that I’m back in town full-time.

(1) I ordered a blind-bearing puller (that didn’t work for a guy on YouTube). I’ll list the puller tool and bearing part number if it works out.

(2) I chamfered the edges of the butterfly shaft in my original TB back in March to prep for the o-ring trick. I’ll let you know how it goes.
 
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What are you using to do a boost leak check?

Update:

I recently used the following kits to do the boost leak test:

Main Test Kit

The main kit allows you to plumb into the manifold and will expose throttle body and HVAC leaks. I did so by hooking the smoker up to the hose that goes to the brake booster.

Coupler Kit for the turbo

I used the coupler kit for testing leaks from the turbo to the manifold. This is probably not necessary unless you are trying to nail down boost leaks.
 
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Having the same issue with the valve shaft leaking, did swapping the TB fix your problem? Has anyone done the O-ring mod like the video shows?

Update (edited):

@Boomer453

I installed O-rings from a Harbor Freight metric Nitrile O-ring kit.

I chose the o-ring with a large enough I.D. that still fit snugly over the shaft. It's pretty obvious which one to use. The old seals are super easy to remove with an angled scribe/pick. I used a little bit if silicone for installing the new rings. You don't need to chamfer the flat end of the butterfly shaft, but I had already done in on one of them. The job is not difficult.

I installed two O-rings on the inside of each bearing for the TB that I've been running for a couple of weeks now. That arrangement seals better than installing one o-ring on the inside & outside of the roller bearings (like I did the other TB).

It's creating and holding boost much better now, so it will handle removing/reducing a vacuum leak.
 
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