drat that pesky CEL for insuff EGR flow
04-10-2008, 01:12 PM
#1
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drat that pesky CEL for insuff EGR flow
ARGGHH. Followed Austinado's wonderful instructions to clean the system (the valve DID hold vacuum so it's OK) and three days later the light is back. Where the valve connects to the int manif there was some carbon but not a huge amount that I cleaned out. Replaced the frayed vac lines with OEM stuff. I shoved some braided steel cable into the hole to clean and it went in about an inch--is that where the famous 90 degree turn is in the system? If so how can I get "around the corner" to clean further in? That bottle of Grey Goose is calling to me on this one. If someone has an answer, my liver will thank you.
04-10-2008, 02:00 PM
#2
You were close, but still so far.....
Having learned my lesson, there's just no getting around the fact that you must remove the throttle body (4 allen bolts and off it comes...re-use the gasket with some Permatex Aviation Form-A-Gasket on it) to do this job properly.
The passage from the actual EGR Valve over to the temp sensor where the 90 degree turn is, is about 8" long (I'm guessing) so that should tell you how clogged your system still is.
You need to put your steel cable into a drill and use carb cleaner as you're augering out that passage.
Then from inside (after removing the throttle body) you take a dental pick and chip out all the carbon from the 1/2" deep x 1/4" diameter hole there.
When it's good and clean, you'll be able to see your frayed cable trying to come up into the intake plenum.
When you're all done, mop up all the cr@p that will be inside the intake plenum, and put her back together.
The passage from the actual EGR Valve over to the temp sensor where the 90 degree turn is, is about 8" long (I'm guessing) so that should tell you how clogged your system still is.
You need to put your steel cable into a drill and use carb cleaner as you're augering out that passage.
Then from inside (after removing the throttle body) you take a dental pick and chip out all the carbon from the 1/2" deep x 1/4" diameter hole there.
When it's good and clean, you'll be able to see your frayed cable trying to come up into the intake plenum.
When you're all done, mop up all the cr@p that will be inside the intake plenum, and put her back together.
04-10-2008, 02:31 PM
#4
Some here take the intake manifold off. To me the T-Body is easier.
<center><img src="http://pictureposter.audiworld.com/57225/egr_port_with_carbon_pile.jpg"></center><p>But, I'm a small guy and it's not a problem to lay up on the engine and work inside the opening in the back of the intake.
Here's the mess you'll find where the EGR exits into the intake plenum. Note that the gasket stayed permantly attached to the plenum. That made it dead easy to give it a light coat of Permatex Aviation Form-A-Gasket and reuse it.
The pile of carbon is what I chipped out of the EGR port that you see there in the photo. It was formed up into a little mountain blocking about 90% of the opening....so from the outside I could put a hose into the intake where the EGR valve bolts up, and blow through the system. This made me think I had it all clean. Obviously not! The other thing all this carbon was doing, is insulating the EGR temp sensor and keeping it from registering proper heat readings for the ECU.
Here's the mess you'll find where the EGR exits into the intake plenum. Note that the gasket stayed permantly attached to the plenum. That made it dead easy to give it a light coat of Permatex Aviation Form-A-Gasket and reuse it.
The pile of carbon is what I chipped out of the EGR port that you see there in the photo. It was formed up into a little mountain blocking about 90% of the opening....so from the outside I could put a hose into the intake where the EGR valve bolts up, and blow through the system. This made me think I had it all clean. Obviously not! The other thing all this carbon was doing, is insulating the EGR temp sensor and keeping it from registering proper heat readings for the ECU.
04-10-2008, 03:02 PM
#5
I hate working in odd positions. I'll remove 100 bolts if it means I can work at the bench.
Aside from that though, taking the whole manifold off means you can easily unscrew the EGR temp sensor and clean it and its passageway also.
In any event, your description of crawling on top of the engine reminded me of this:
<img src="http://pictureposter.audiworld.com/43812/clutch_slaves.jpg">
I am not the one in this picture who thought nothing of hopping up onto the fender to get to the slave cylinder...
In any event, your description of crawling on top of the engine reminded me of this:
<img src="http://pictureposter.audiworld.com/43812/clutch_slaves.jpg">
I am not the one in this picture who thought nothing of hopping up onto the fender to get to the slave cylinder...
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04-10-2008, 04:10 PM
#8
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I remember trying to get that damn thing back in when I did the clutch.
If I remember right it took two people, two sets of pry bars, tons of swearing, and a second set of elbows, and it looked remarkably like your picture.
04-11-2008, 05:30 AM
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Re: You were close, but still so far.....
Hey Austinado, you are the resident sees all, knows all omnipotent potentate and all around guru of C4's, thanks so much for the helpful info. Looks like more quality bonding time with the Audi this weekend. Need to get all this stuff done as the car is moving from Buffalo to Memphis in June so some long drives are in the near future.