Picture of 5.4 throttle body before cleaning it 22k miles ago. The TB-EGR passageway has never been cleaned and I'm assuming it looks as messy or worse. So, even though there's no codes or other trouble indicated, would you clean it anyway?
Cleaning throttle body to EGR valve passageway
- Thread starter jr1under
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jr1under
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Let me restate the question...
I've read a lot in this forum and elsewhere about P0401(Insufficient EGR Flow) in Gen1's. Consensus is the first fix attempted should be to clean the throttle body and its passageway to the EGR valve.
Is it worthwhile to clean the passageway now even though there's no trouble indicated?
I've read a lot in this forum and elsewhere about P0401(Insufficient EGR Flow) in Gen1's. Consensus is the first fix attempted should be to clean the throttle body and its passageway to the EGR valve.
Is it worthwhile to clean the passageway now even though there's no trouble indicated?
99WhiteC5Coupe
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Wow - the throttle body inside looks bade.
Do you have a rough idle? Is there any indication of a clogged EGR passageway, other than the dirty throttle body bore?
In the 1970’s - I had a 1973 Corvette with the 350 CID L-48 engine - with an EGR valve attached to the intake manifold, off to the side of the carburetor.
I replaced the EGR valve due to a diaphragm leak. When I removed the valve, I could see the EGR passageway was almost closed off with carbon.
The intake manifold had to be removed and soaked in a solvent, then a brush run through it to clear it.
I’d say the cleaning is your call - can you inspect it? How hard is it to clean?
Do you have a rough idle? Is there any indication of a clogged EGR passageway, other than the dirty throttle body bore?
In the 1970’s - I had a 1973 Corvette with the 350 CID L-48 engine - with an EGR valve attached to the intake manifold, off to the side of the carburetor.
I replaced the EGR valve due to a diaphragm leak. When I removed the valve, I could see the EGR passageway was almost closed off with carbon.
The intake manifold had to be removed and soaked in a solvent, then a brush run through it to clear it.
I’d say the cleaning is your call - can you inspect it? How hard is it to clean?
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jr1under
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Haven't done it before but suppose I can inspect one end of it by pulling off the EGR valve. Would have to do that anyway if the whole TB assembly needs cleaning.
Pulling out the assembly seems simple enough but I'm always leery of unintended consequences when doing something for the first time. Little did he know...
99WhiteC5Coupe
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If you can easily get the EGR off - the pintle end should tell if the passageway is clogged with carbon.
Good luck - let us know what you do.
I wish I had that advice three days ago. I am working on my 02 eb 5.4 and
i broke that special bolt off because of that carbon and they don't make them anymore.
All the junk yards are broke off (go figure) so I am going to get a longer bolt and put a sleeve on it.
(just have to drill out the bracket a little)
So I have taken the whole throttle body off to bench fix the broken off bolt with a drill and some new threads.
It is very dirty inside but I am afraid to try and clean it to not get it done right and have a bunch of loose pieces.
I think I will be careful around the edges and gaskets for loose stuff. Other than that I am going to leave it alone.
Never have had any codes or loss of power before.
Never had codes before and mine is just as dirty looking, worse even back at the EGR valve.
Just going to clean up anything I knocked loose working on it and that's it.
I did not have any codes but had a loss in power. Replaced the EGR valve and Cleaned the intake manifold as deep as I was able to go without removing it. Full power restored to my ‘98 Expy. Your throttle intake looks bad I would clean it.
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jr1under
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Gotta admit, I had to look up what a pintle is, learned it's sometimes paired to a gudgeon. Still not exactly sure so I'm posting multiple pictures.
The EGR came off easier than expected, nothing was corroded in place. It also looks way better than expected considering how bad the TB intake looked before it was cleaned. I'm wondering now if the best course of action is to just reinstall it.
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jr1under
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Is this the bolt that broke?
Your situation is the worst, inspecting what turns out to be a non-problem but breaking something else in the process. How to turn an hour into three days.
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