Carbon Build-up in EGR and Intake Manifold
08-30-2002, 11:31 AM
#41
Member
Join Date: Mar 2002
Posts: 118
White96MaxSE,
I would like to do this as well but right now I can't visualize these pipes that you talk of. Do you have pics of this or anyone else has some? I took off my throttle body to clean it, and it made a real noticable difference.
Thanks,
magic_max
'96SE
I would like to do this as well but right now I can't visualize these pipes that you talk of. Do you have pics of this or anyone else has some? I took off my throttle body to clean it, and it made a real noticable difference.
Thanks,
magic_max
'96SE
Originally posted by White96MaxSE
Hi asianpr3082;
Good information.
I have 175,000 miles on my maxima.
I went ahead and bought the Large EGR Pipe and the small EGR Pipe and I am planning on simply swapping the new pipes onto the car in place of the carbon filled ones.
Then, I can try to clean up the two pipes I remove for some future swap again.
I received the Large EGR Pipe today and I took it to Sears and tried to find a crow foot. Craftsman stocks only up to 19 mm, but I did confirm that the large end (that connects to the EGR Valve) is 30 mm, and the small end (that connects to the exhaust manifold) is 24 mm.
The large nut can be gotten to with a large wrench so it isn't a problem. The other end is in tight quarters.
In a previous post in this thread it was mentioned that I may need a crow-foot to get at the nut on the exhaust manifold to remove this large EGR pipe.
Craftsman has a 19 mm, but Snap-On goes to 24 mm, so now I need to find a Snap-On truck and buy a 24mm crow foot.
The small EGR pipe didn't come in so I am going to wait another week to do the next phase of this project.
Cold starting is much better!
Hopefully, my detailing this information will help someone else down the road.
White96MaxSE
Hi asianpr3082;
Good information.
I have 175,000 miles on my maxima.
I went ahead and bought the Large EGR Pipe and the small EGR Pipe and I am planning on simply swapping the new pipes onto the car in place of the carbon filled ones.
Then, I can try to clean up the two pipes I remove for some future swap again.
I received the Large EGR Pipe today and I took it to Sears and tried to find a crow foot. Craftsman stocks only up to 19 mm, but I did confirm that the large end (that connects to the EGR Valve) is 30 mm, and the small end (that connects to the exhaust manifold) is 24 mm.
The large nut can be gotten to with a large wrench so it isn't a problem. The other end is in tight quarters.
In a previous post in this thread it was mentioned that I may need a crow-foot to get at the nut on the exhaust manifold to remove this large EGR pipe.
Craftsman has a 19 mm, but Snap-On goes to 24 mm, so now I need to find a Snap-On truck and buy a 24mm crow foot.
The small EGR pipe didn't come in so I am going to wait another week to do the next phase of this project.
Cold starting is much better!
Hopefully, my detailing this information will help someone else down the road.
White96MaxSE
08-30-2002, 03:22 PM
#42
Donating Maxima.org Member
Thread Starter
Join Date: Jan 2002
Posts: 245
Hi magic_max;
I don't yet have a digital camera, and thus I have no pictures to help you with this project.
When the car is cold you can lean over the top of the engine toward the firewall on the passenger side and you may be able to barely see the large EGR pipe where is is attached to the top of the Exhaust Manifold on the back side of the engine.
The other end of this pipe goes to the EGR valve on the side of the engine on the driver's side.
The small EGR pipe goes from the EGR valve up to the back and bottom of the intak manifold and I think 1max2nv did post pictures in this thread of this back side of the intake manifold.
There are pictures of the EGR valve in the Haynes manual, although they are not great pictures you might look at them.
Hope this helps a bit.
White96MaxSE
I don't yet have a digital camera, and thus I have no pictures to help you with this project.
When the car is cold you can lean over the top of the engine toward the firewall on the passenger side and you may be able to barely see the large EGR pipe where is is attached to the top of the Exhaust Manifold on the back side of the engine.
The other end of this pipe goes to the EGR valve on the side of the engine on the driver's side.
The small EGR pipe goes from the EGR valve up to the back and bottom of the intak manifold and I think 1max2nv did post pictures in this thread of this back side of the intake manifold.
There are pictures of the EGR valve in the Haynes manual, although they are not great pictures you might look at them.
Hope this helps a bit.
White96MaxSE
Originally posted by magic_max
White96MaxSE,
I would like to do this as well but right now I can't visualize these pipes that you talk of. Do you have pics of this or anyone else has some? I took off my throttle body to clean it, and it made a real noticable difference.
Thanks,
magic_max
'96SE
White96MaxSE,
I would like to do this as well but right now I can't visualize these pipes that you talk of. Do you have pics of this or anyone else has some? I took off my throttle body to clean it, and it made a real noticable difference.
Thanks,
magic_max
'96SE
03-29-2003, 08:06 PM
#43
I know this is an old post, but it is informative. . . I was just wondering if someone could post pictures of what is being talked about (small pipe, large pipe, hole where most of the clogging occurs)
03-31-2003, 05:40 PM
#46
Donating Maxima.org Member
Thread Starter
Join Date: Jan 2002
Posts: 245
This was my first thread on the .org, and it is amazing that it has been about 1 year now since my first posting it.
I still don't have a digital camera to help you guys out with this project.
Oddly enough, though, I performed this EGR work on my best buddie's 1996 5-speed Maxima with 100,000 miles on it just last weekend.
The task is fresh in my mind, and I just recently reread the entire thread. Brubenstein's suggestions and descriptions and 1Max2NV's help stand out as very important insights to pay attention to here.
I'm hoping that someone will be able to provide some pictures for this project, but not me at this time.
White96MaxSE
I still don't have a digital camera to help you guys out with this project.
Oddly enough, though, I performed this EGR work on my best buddie's 1996 5-speed Maxima with 100,000 miles on it just last weekend.
The task is fresh in my mind, and I just recently reread the entire thread. Brubenstein's suggestions and descriptions and 1Max2NV's help stand out as very important insights to pay attention to here.
I'm hoping that someone will be able to provide some pictures for this project, but not me at this time.
White96MaxSE
03-31-2003, 07:51 PM
#47
Supporting Maxima.org Member
iTrader: (54)
Join Date: Feb 2001
Location: Northern Jersey
Posts: 10,166
Well I wanted to perform this before I put my manifold back on because it is probably easier with the manifold off ?
From the back of the manifold down and around, is that the small tube ??
When I took the stock manifold off, the deposits on the back of the manifold that connect to that peices with 2 bolts was pretty caked up
what to do ??
-matt
From the back of the manifold down and around, is that the small tube ??
When I took the stock manifold off, the deposits on the back of the manifold that connect to that peices with 2 bolts was pretty caked up
what to do ??
-matt
03-31-2003, 10:20 PM
#48
Donating Maxima.org Member
Thread Starter
Join Date: Jan 2002
Posts: 245
Originally posted by matty
Well I wanted to perform this before I put my manifold back on because it is probably easier with the manifold off ?
From the back of the manifold down and around, is that the small tube ??
When I took the stock manifold off, the deposits on the back of the manifold that connect to that peices with 2 bolts was pretty caked up
what to do ??
-matt
Well I wanted to perform this before I put my manifold back on because it is probably easier with the manifold off ?
From the back of the manifold down and around, is that the small tube ??
When I took the stock manifold off, the deposits on the back of the manifold that connect to that peices with 2 bolts was pretty caked up
what to do ??
-matt
Yes, the small EGR tube is the one that is attached to the back of the intake manifold on one end, and attaches to the side of the block on the other end, but you must remove the Large EGR pipe (the one that attaches to the Exhaust Manifold on one end and to the EGR valve on the driver's side of the block on the other.
Reread the thread, I have explained all of this in great detail here already.
White96MaxSE
07-19-2003, 03:12 PM
#50
Has this been added to the FAQ yet.. because i've seached through about 2 dozen threads on this that all end with unanswered questions. Info in this one answers most of those.. except the part about pics.
12-25-2004, 10:41 AM
#53
Senior Member
Join Date: Feb 2004
Posts: 654
Originally Posted by White96MaxSE
Hi asianpr3082;
That hole in the picture that 1Max2NV provided on this thread is the the endpoint of the EGR system.
Exhaust Gas Recirculation takes Exhaust Gas from the Exhaust manifold and sends it through again to be reburnt a second time to cut down on emissions and thus carries that damn carbon into the engine.
The path of the Exhaust Gas starts at the exhaust manifold, runs through the Large EGR Pipe to the EGR valve, through the EGR valve into the small EGR pipe which attaches to the outside of the intake manifold on the backside. This is the smaller of the two holes in the intake in the other picture that 1MaxNV provided in this thread.
Where the small EGR pipe attaches to the manifold is the passageway whereby the exhaust gases are delivered into the intake manifold to mix with the normal fresh air and fuel are being delivered to the cylinders via the intake manifold.
The hole that we are taking about is the point where all of the crap builds up I suspect because the hot exhaust gases meet the cold normal intake mixture at that point and this causes the gas to dump carbon and other crap it is carrying at that point.
You have got to get that hole (the entire passageway) and also the EGR pipes clear of carbon buildup if you want to have a smooth and uninterrupted flow of exhaust gas and insure that the EGR valve can function properly.
I hope this helps.
White96MaxSE
That hole in the picture that 1Max2NV provided on this thread is the the endpoint of the EGR system.
Exhaust Gas Recirculation takes Exhaust Gas from the Exhaust manifold and sends it through again to be reburnt a second time to cut down on emissions and thus carries that damn carbon into the engine.
The path of the Exhaust Gas starts at the exhaust manifold, runs through the Large EGR Pipe to the EGR valve, through the EGR valve into the small EGR pipe which attaches to the outside of the intake manifold on the backside. This is the smaller of the two holes in the intake in the other picture that 1MaxNV provided in this thread.
Where the small EGR pipe attaches to the manifold is the passageway whereby the exhaust gases are delivered into the intake manifold to mix with the normal fresh air and fuel are being delivered to the cylinders via the intake manifold.
The hole that we are taking about is the point where all of the crap builds up I suspect because the hot exhaust gases meet the cold normal intake mixture at that point and this causes the gas to dump carbon and other crap it is carrying at that point.
You have got to get that hole (the entire passageway) and also the EGR pipes clear of carbon buildup if you want to have a smooth and uninterrupted flow of exhaust gas and insure that the EGR valve can function properly.
I hope this helps.
White96MaxSE
05-16-2005, 08:09 PM
#57
I know this thread is kind of old, but its one of the best in the forum. And this might be a dumb question, but the gaskets to the EGR Guide PIPE (Small pipe) that can only be purchased at a Nissan Dealership? ANd what is the part numbers including the EGR Valve Gasket.
05-21-2005, 10:56 PM
#61
Junior Member
Join Date: May 2005
Location: Detroit - suburbs
Posts: 37
Cleaned out my EGR System but more problems came up
Hi, this is my first post on here so take it easy on me if I make mistakes and ask stupid questions. I have read this entire thread and did every thing that White96MaxSE did with his, except for: I didn't take off the larger pipe that goes from the exhaust to the EGR Valve, I just took the small one off. Well after taking everything off, and cleaning it very well, with TB cleaner I am now seeing more problems with my acceleration at about 2700 rpm.
Before this cleaning I had a P0400 - EGR Flow Malfunction
Now after cleaning the whole system practically; (EGR valve, path from EGR valve to intake manifold and inside the manifold) I have a new code
P0403 EGR Flow Circuit Malfunction.
Problems I was having before:
RPM would rise by about 100 and then sink back down by 100 when I was idling at stoplights (in drive). And I would feel a slight shake when that was happening as if it was about to die.
Problems I have now:
Same as above with at about 2700 RPM if I accelerate a little harder, the car feels like it's going to stall but instead it just just coughs almost. and seems like it doesn't want to go past that 2700 rpm and just keeps coughing if I keep my foot on the gas. Very strange.
Only thing I can guess is that my valve wasn't working right from the beggining (probably was staying open too long, or just not closing all the way- letting exhaust into air intake) and now that the passages are all clean, it's leting way too much exhaust in with the clean air and making things worse...
Questions I have:
1. Anyone experience this before?
2. What pushes the exhaust gas from the exhaust manifold to go into the EGR Valve?
3. Assumption: the harder I accelerate the more exhaust gas comming out and being rushed into EGR Valve which is staying open <-- assumption, and then freely mixing with clean air in the intake manifold...
4. Can the electronic component atached to the top of the mechanical portion of the EGR Valve be tested with an ohm meter or something?
That's where I'm at, next step is going to buy a new EGR Valve, hope the electronic circuitry above the mechanical valve is included, never bought one.
Thanks in advance for any suggestions.
99 Maxima GLE
96K miles, all stock
if anyone still needs those part numbers let me know I have a printout from the dealer with the partnumbers on it, and they can tell you over the phone too what the part numbers are.
Before this cleaning I had a P0400 - EGR Flow Malfunction
Now after cleaning the whole system practically; (EGR valve, path from EGR valve to intake manifold and inside the manifold) I have a new code
P0403 EGR Flow Circuit Malfunction.
Problems I was having before:
RPM would rise by about 100 and then sink back down by 100 when I was idling at stoplights (in drive). And I would feel a slight shake when that was happening as if it was about to die.
Problems I have now:
Same as above with at about 2700 RPM if I accelerate a little harder, the car feels like it's going to stall but instead it just just coughs almost. and seems like it doesn't want to go past that 2700 rpm and just keeps coughing if I keep my foot on the gas. Very strange.
Only thing I can guess is that my valve wasn't working right from the beggining (probably was staying open too long, or just not closing all the way- letting exhaust into air intake) and now that the passages are all clean, it's leting way too much exhaust in with the clean air and making things worse...
Questions I have:
1. Anyone experience this before?
2. What pushes the exhaust gas from the exhaust manifold to go into the EGR Valve?
3. Assumption: the harder I accelerate the more exhaust gas comming out and being rushed into EGR Valve which is staying open <-- assumption, and then freely mixing with clean air in the intake manifold...
4. Can the electronic component atached to the top of the mechanical portion of the EGR Valve be tested with an ohm meter or something?
That's where I'm at, next step is going to buy a new EGR Valve, hope the electronic circuitry above the mechanical valve is included, never bought one.
Thanks in advance for any suggestions.
99 Maxima GLE
96K miles, all stock
if anyone still needs those part numbers let me know I have a printout from the dealer with the partnumbers on it, and they can tell you over the phone too what the part numbers are.
05-22-2005, 01:09 AM
#62
sounds like MAF sensor failure. Check to see if the code shows, otherwise one alternative to check if it's the MAF is to disconnect the wiring harness and accelerate the car. If the same thing happens then it's definately your MAF. You must've somehow got it wet with the TB cleaner.. or you left it wet and when the butterfly opened it splashed out and hit the sensor. Or it might have been it's time to blow.
Get an MAF at a junkyard or autowrecking place.. it might run you close to $100 or so. As for the EGR failure, I really needed my car for commuting purposes so I rented a car and left the max at the dealer and let them do it... i had a friend there though, so it was cheaper than usual. Otherwise I would have busted a DIY job.. i just didn't have that kind of time.
Get an MAF at a junkyard or autowrecking place.. it might run you close to $100 or so. As for the EGR failure, I really needed my car for commuting purposes so I rented a car and left the max at the dealer and let them do it... i had a friend there though, so it was cheaper than usual. Otherwise I would have busted a DIY job.. i just didn't have that kind of time.
05-22-2005, 06:01 AM
#63
Junior Member
Join Date: May 2005
Location: Detroit - suburbs
Posts: 37
MAF sensor
Thanks, I'll try disconnecting the MAF sensor and see if it still does it, but I was watching my dash as I was accelerating and right when it hit that 2700 rpm and the car started jerking back and forth is when the Service Engine Soon came on, and the only code that was registered was the P0403 which the scanner reports as "EGR Flow Circuit Malfunction".
And before cleaning out that entire EGR System I only had the P0400 which was a simple more generic "EGR Flow Malfunction"
But I will sure try disconnecting the MAF and see how it works.
And before cleaning out that entire EGR System I only had the P0400 which was a simple more generic "EGR Flow Malfunction"
But I will sure try disconnecting the MAF and see how it works.
05-22-2005, 06:41 AM
#64
Senior Member
Join Date: Mar 2005
Posts: 625
my manager at my old job told me of a way to help remove some carbon buildup in the system. there is this liquid formula thing that is caled Sea Foam. he removed a vacuum hose off of the back of the manifold i assume and put one end of a small funnel to the hose.(the other end is still attached to the manifold) he then started the car up but it hesitated due to a leak in vacuum then slowly poured the sea foam through the funnel then let it go through the intake manifold. i read the bottle of the sea foam and it says that it removes carbon buildup. so i let him do it and my max jus started releasing lots and lots of white smoke from the exhaust for about 5mins. (carbon buildup)
after driving it for a couple of daYS i noticed a change. there really wasnt any more hesitation when i take off. i dunno if its me or its a mental feeling. but it did work
after driving it for a couple of daYS i noticed a change. there really wasnt any more hesitation when i take off. i dunno if its me or its a mental feeling. but it did work
05-22-2005, 06:56 AM
#65
Guest
Posts: n/a
ya sea foam is used to clean light carbon build up in the motor. sea foam isnt going to clean your entire motor out. a few months ago i got 2 codes egr valve and knock sensor. and i wasnt about to spend a ton of money on a new egr and knock sensor.
so i removed the upper intake manifold and throttle body and holy shat was there a ton of black carbon build up. i cleaned the upper intake manifold out and the throttle body and then i sent them out to a machine shop they bored out the throttle body and ported the upper intake manifold 40 dollars wasnt to bad. next i removed the egr valve and that was 100% blocked with carbon. i removed and cleaned the egr valve. next i reinstalled everything
ever since doin this i've been using sea foam
so i removed the upper intake manifold and throttle body and holy shat was there a ton of black carbon build up. i cleaned the upper intake manifold out and the throttle body and then i sent them out to a machine shop they bored out the throttle body and ported the upper intake manifold 40 dollars wasnt to bad. next i removed the egr valve and that was 100% blocked with carbon. i removed and cleaned the egr valve. next i reinstalled everything
ever since doin this i've been using sea foam
05-22-2005, 10:36 AM
#67
Originally Posted by MaxxAddict
Why can't one just unplug the EGR pipes at the exhaust manifold? I realize that this would hurt emissions, but wouldn't you gain HP due to no more exhaust gas being recirculated into the engine? You'd be bringing in only FRESH, clean air.
)
09-12-2005, 06:53 AM
#69
Member
Join Date: Oct 2002
Posts: 29
This is a great post. I was able to remove the throttle body and the EGR smaller pipe was completely clogged. I wouldn't have know what to do if it wasn't for this post. I was getting EGR codes and Knock sensor codes. After I put it all back together I got O2 sensor codes. Possibly due to all the T.B. cleaner I used. I have reset the ECU and it has been off for three days and running stronger than it has in a long time. It took about 4 hours. It all went very well, no problems and nothing broken. I think if I have to do it again I will try just removing the small pipe and try cleaning it that way first. To save a little time. Has anyone tried doing it that way? Thanks for all the great information. So I should be set for another 200,000 miles, you think?
11-02-2005, 12:56 PM
#71
Newbie - Just Registered
Join Date: Sep 2005
Posts: 5
BG products to clean EGR system?
Has anyone tried to use a service that uses BG products to clean the EGR system? I was wondering if anyone has had any success with this type of service.
I am getting the same EGR codes just like everyone else. I heard that this service requires the EGR valve to be removed and chemicals are pumped in. This process eventually cleans out the whole EGR system. It costs around $200 for this.
I tried to get at the small pipe this weekend but I could not get the large pipe to the EGR valve removed so this prevented me to remove the smaller pipe. I put everything back together becuase I couldn't loosen up the large pipe.
The service guy said Maxima's have a problem with EGR system to get clogged so atleast he was familiar with this problem.
I am getting the same EGR codes just like everyone else. I heard that this service requires the EGR valve to be removed and chemicals are pumped in. This process eventually cleans out the whole EGR system. It costs around $200 for this.
I tried to get at the small pipe this weekend but I could not get the large pipe to the EGR valve removed so this prevented me to remove the smaller pipe. I put everything back together becuase I couldn't loosen up the large pipe.
The service guy said Maxima's have a problem with EGR system to get clogged so atleast he was familiar with this problem.
11-02-2005, 01:35 PM
#73
Newbie - Just Registered
Join Date: Sep 2005
Posts: 5
BR products
Originally Posted by njmodi
I tried calling almost every local dealer listed on the BG website, but none of them offered the EGR cleaning (BG flush). If you can find a place to do it, go for it.
There is a local Goodyear tire place that does other service also and this BG service is included. The air and induction service cost around $100 but the EGR service is $200. They even had clogged EGR valve shown in a small enclosed display enclosure.
It's unfortunate that you couldn't find any one. I hear BG product advertisement mentioned on one of the sports radio stations all the time. I think the talk radio guy on Saturdays, Likus, shows BG products on his website. I am thinking this stuff must do the job.
11-02-2005, 01:39 PM
#74
Originally Posted by vpmax2
There is a local Goodyear tire place that does other service also and this BG service is included. The air and induction service cost around $100 but the EGR service is $200. They even had clogged EGR valve shown in a small enclosed display enclosure.
It's unfortunate that you couldn't find any one. I hear BG product advertisement mentioned on one of the sports radio stations all the time. I think the talk radio guy on Saturdays, Likus, shows BG products on his website. I am thinking this stuff must do the job.
It's unfortunate that you couldn't find any one. I hear BG product advertisement mentioned on one of the sports radio stations all the time. I think the talk radio guy on Saturdays, Likus, shows BG products on his website. I am thinking this stuff must do the job.
11-02-2005, 01:55 PM
#76
Originally Posted by GREENlight
White96MaxSE, how much is this cleaning running for at the dealership?
11-02-2005, 02:26 PM
#77
not sure if anyone has seen this at all, but if you could find somewhere to buy this.... make a few bucks on the side charge half the price of the dealership.
http://www.bgprod.com/products/image...l-Kit600px.jpg
found it here
http://www.bgprod.com/products/fuelair.html#9240
well found out they only sell through distributors so if someone could call up and act like a auto repair place heres the distributor for those in or around NY
BG Metro
P.O. Box 385
Matawan, NJ 07747
USA
917.363.9147
http://www.bgprod.com/products/image...l-Kit600px.jpg
found it here
http://www.bgprod.com/products/fuelair.html#9240
well found out they only sell through distributors so if someone could call up and act like a auto repair place heres the distributor for those in or around NY
BG Metro
P.O. Box 385
Matawan, NJ 07747
USA
917.363.9147
11-03-2005, 11:51 AM
#78
Newbie - Just Registered
Join Date: Sep 2005
Posts: 5
Just curious about everyone who has either replaced or cleaned the small tube in the EGR system. Did you find any residue in the EGR valve iteself. It seems more than likely, if the small tube gets all clogged up then shouldn't the other parts be in similar situation.
It seems like that really the only way to clean everything it by doing a complete "cleanse" of the system. Any thoughts on this?
I understand that just cleaning the blockage will clear the problems, but wouldn't cleaning the whole system be a more complete approach or is it not necessary?
Thanks for the feedback.
It seems like that really the only way to clean everything it by doing a complete "cleanse" of the system. Any thoughts on this?
I understand that just cleaning the blockage will clear the problems, but wouldn't cleaning the whole system be a more complete approach or is it not necessary?
Thanks for the feedback.
11-03-2005, 11:59 AM
#79
Originally Posted by vpmax2
Just curious about everyone who has either replaced or cleaned the small tube in the EGR system. Did you find any residue in the EGR valve iteself. It seems more than likely, if the small tube gets all clogged up then shouldn't the other parts be in similar situation.
It seems like that really the only way to clean everything it by doing a complete "cleanse" of the system. Any thoughts on this?
I understand that just cleaning the blockage will clear the problems, but wouldn't cleaning the whole system be a more complete approach or is it not necessary?
Thanks for the feedback.
It seems like that really the only way to clean everything it by doing a complete "cleanse" of the system. Any thoughts on this?
I understand that just cleaning the blockage will clear the problems, but wouldn't cleaning the whole system be a more complete approach or is it not necessary?
Thanks for the feedback.
11-03-2005, 12:38 PM
#80
Newbie - Just Registered
Join Date: Sep 2005
Posts: 5
Actually this makes alot of sense. What do you consider a long long time driving around with this condition... Several weeks or several months?
I noticed the right angle bend and obviously the larger particles will be confronted with some kind of resistance. Enough of these kind of components flowing through there will eventually stack up on each other and start to clog the line.
Is this side of the small pipe difficult to remove the bolts? If just the intake manifold is removed, the small pipe will just stay there open. Did you see the clogging in the pipe and if so how did you clean that? I don't want to attempt to open the EGR part of the system again as I had minimal luck doing so.
How difficult was it to remove the manifold and that side of the tube? Did you replace the gasket on the manifold also?
I noticed the right angle bend and obviously the larger particles will be confronted with some kind of resistance. Enough of these kind of components flowing through there will eventually stack up on each other and start to clog the line.
Is this side of the small pipe difficult to remove the bolts? If just the intake manifold is removed, the small pipe will just stay there open. Did you see the clogging in the pipe and if so how did you clean that? I don't want to attempt to open the EGR part of the system again as I had minimal luck doing so.
How difficult was it to remove the manifold and that side of the tube? Did you replace the gasket on the manifold also?