what is the EGR mod, what does it do and ...

unclebob

Well-known member
Joined
Feb 11, 2001
Location
college station, tx
TDI
silver 02 Golf GLS
I've read in several threads about an EGR mod. What is it, what does it do and any warranty issues ? Also, any "legal" issues, as in emissions ?

I have a 2002 Golf TDI with 30K on it. I did do a search but never really read any specific answers on this.
 

Deech

Member
Joined
Aug 3, 2004
TDI
Jetta GLS, 2004, Galactic Blue
From the TDIFAQ:

Avoiding the Need for Intake Manifold Cleaning - Recalibrating the EGR System - this vehicle is equipped with a CCV (crankcase vent) system and an EGR (exhaust gas recirculation) system. Oily fumes from the CCV system can combine with carbon particles from the EGR system to form a black sticky tar in the intake system. This eventually starts restricting the amount of airflow into the engine, resulting in gradual power loss as the vehicle ages and the intake clogging becomes worse. In rare cases a MIL ("check engine" light) may be tripped, with an intake manifold pressure control code set, but normally this does not happen and no codes are set. Operating conditions, fuel quality, oil quality, driving habits, and general condition of the engine all have some effect on how long the intake system survives before clogging up. It can be prevented and this recalibration is highly recommended for all TDI owners.

A VW specific scan tool such as VAG-COM is required for this procedure. With the engine warmed up and running at idle in neutral with all major accessories such as air conditioning turned off, connect the scan tool cable and start the scan tool software. Select engine control module. "Login" using 12233 as the access code. Select "adaptation" and go to adaptation block 3. Give the accelerator pedal a quick "blip" to ensure that the EGR remains turned on for the next minute while you perform the following steps. Note that the display shows a default adaptation value of 32768 and shows approximately 250 +/- 20 mg/stroke of air intake volume. (If it does not show this, you are either on the wrong screen, or you have an older ECU that differs slightly - see next paragraph.) If all is well, enter 33768 as the new adaptation value, and select "test". Note that the displayed air intake volume changes, usually to about 370 mg/stroke. The specification limit is 370 mg/stroke, so if you want to remain within OEM shop manual specifications for emission control reasons, you might have to enter a number slightly smaller than 33768. (If you don't care about road-legal NOx emission limits then leave it at 33768. [Depending on the usage cycle, NOx at this setting can be increased by as much as 40%]) If all is well and you have a seting that you are happy with which results in an intake air volume of 370 mg/stroke or just a hair less, enter "save". Now your intake manifold either will never clog, or will take so long that the engine will wear out first.

Note for '96 Passat and possibly other older ECU variations: The adaptation numbers are in a different range, and you won't be able to get feedback on what you are doing on the same screen. The EGR adaptation number for a '96 Passat with the original "BK" ECU is 188 rather than 33768 and you'll have to go back to "measuring blocks" group 3 to see the effect before "saving" the new setting.
As for warranty, no one has mentioned any problems nor should there be. This adjustment is also completely reversable should one be concerned.
Most provinces and states that do emissions testing on diesels, just check opacity, so this will not be a factor when testing.
 

toml

Member
Joined
Aug 27, 2004
Location
Elida, Ohio
TDI
Jetta, 2004, Blue
This Login does not work for me. I just received the Vag_Com package yesterday and gave it a try on this topic. This was on a new 2004 Jetta. The 12233 access code was an invalid login for my Engine Controller.
 

toml

Member
Joined
Aug 27, 2004
Location
Elida, Ohio
TDI
Jetta, 2004, Blue
Thanks for that information. Maybe the FAQ will need some updating and some note about the differences between the PD and the other engines. I have had my Jetta for one month and the Vag-Com scanner for a day. I was just looking through the controller list and gave EGR tuning procedure a try. I was surprised when the Access Code in the FAQ was invalid. I thought that something was missed when I configured the scanner software.
 

mgwerks

Veteran Member
Joined
Dec 10, 2003
Location
Texas Hill Country
TDI
black 1999 New Beetle
I've read in several threads about an EGR mod. What is it, what does it do and any warranty issues ? Also, any "legal" issues, as in emissions ?
I have a 2002 Golf TDI with 30K on it. I did do a search but never really read any specific answers on this.
Don't bother doing it. Leave your EGR setting as is. It was thought that reducing EGR would eliminate intake clogging - it doesnt. Get a good CCV solution like an Eclipse or ON CCV. Keeping the oil out will do the trick.
 

AndyBees

Top Post Dawg
Joined
May 27, 2003
Location
Southeast Kentucky
TDI
Silver 2003 Jetta TDI, Silver 2000 Jetta TDI (sold), '84 Vanagon with '02 ALH engine
If there is nothing but clean air and oily vapors going thru the intake system, how does it continue to clog after doing the EGR mod?

I did the mod back in July of this year. I am not sure about continued clogging, but according to my Excel Spreadsheet, the fuel economy has improved about 6 or 7%. The improvement is reflected in l0 of the last 12 fill-ups. The two fill-ups with poor fuel economy were above the overall average of 51.19 mpg. Also, those tanks involved considerable "city" driving while on vacation in Orlando and some hard driving running north to get out of Florida before hurricane Francis arrived.
 

AndyBees

Top Post Dawg
Joined
May 27, 2003
Location
Southeast Kentucky
TDI
Silver 2003 Jetta TDI, Silver 2000 Jetta TDI (sold), '84 Vanagon with '02 ALH engine
If there is nothing but clean air and oily vapors going thru the intake system, how does it continue to clog after doing the EGR mod?

I did the mod back in July of this year. I am not sure about continued clogging, but according to my Excel Spreadsheet, the fuel economy has improved about 6 or 7%. The improvement is reflected in l0 of the last 12 fill-ups. The two fill-ups with poor fuel economy were above the overall average of 51.19 mpg. Also, those tanks involved considerable "city" driving while on vacation in Orlando and some hard driving running north to get out of Florida before hurricane Francis arrived.
 

GoFaster

Moderator at Large
Joined
Jun 16, 1999
Location
Brampton, Ontario, Canada
TDI
2006 Jetta TDI
Adjusting the EGR setting does not completely turn off the EGR system. It only puts it right at the lower limit of what the factory specifications in the shop manual allow.

With additional experience, there have been mixed reports of whether adjusting the EGR setting is effective. Some cars clog intake manifolds, and some don't. Mine doesn't. I cannot see how less EGR would result in the same amount of clogging.

I think the reality is that adjusting the EGR setting slows down the rate of clogging in general (think "averaged over large number of vehicles"), but if other factors mean that your particular vehicle is going to clog up no matter what, then it's going to clog up.

Adjusting the EGR setting results in a vehicle that is still within manufacturer's operating specifications (although right at the outer edge). It could be argued that this is still legal. Disabling the EGR completely is, without question, "tampering with emission controls". Whether this is meaningful to YOU or not is left to the reader to decide ... We can't publicly condone tampering with emission controls; it's inviting trouble from the feds ...
 

SoCalJames

Veteran Member
Joined
Oct 10, 2000
Location
OC, CA
TDI
I no longer own a TDI
Perhaps your's hasn't clogged partly because of your fuel. Isn't the Canadian diesel "low sulphur?" When I lived near Windsor, ON, I would often drive there to get Sunoco Gold. I think it was something like 150ppm sulphur.
 

cram51

Veteran Member
Joined
Jul 24, 2004
Location
Illinois - St. Louis Area
TDI
2005 Jetta - Spice Red
I've read in several threads about an EGR mod. What is it, what does it do and any warranty issues ? Also, any "legal" issues, as in emissions ?
I have a 2002 Golf TDI with 30K on it. I did do a search but never really read any specific answers on this.
Don't bother doing it. Leave your EGR setting as is. It was thought that reducing EGR would eliminate intake clogging - it doesnt. Get a good CCV solution like an Eclipse or ON CCV. Keeping the oil out will do the trick.
This topic of conversation interests me greatly. I'm about to buy a 2005 Jetta TDI and want to get the most miles out of it I can. I was considering doing the VAG-COM adjustment that was listed above, but it sounds like the program codes are too old for my 2005. Then I read your contribution mgwerks. Where could I go about getting this CCV (Eclipse or ON CCV)? Also, does it void warranty to do something like this?

Also, about the VAG-COM programming. Does anyone have the up to date codes for programming it (for a 2005)? Or is the 2005 got technology to where the EGR is not a problem? It doesn't clog the intake manifold would be a great thing to hear. I would love to hear that VW has solved this problem in their most latest model.
 

IndigoBlueWagon

TDIClub Enthusiast, Principal IDParts, Vendor , w/
Joined
Aug 16, 2004
Location
South of Boston
TDI
'97 Passat, '99.5 Golf, '02 Jetta Wagon, '15 GSW
So from reading this and other threads I understand:

- The EGR mod may not reduce intake clogging
- The mod will create a sluge that has to go somewhere (belly pan seems most likely)
- If you try to optimize timing with the EGR modded you may have some kind of trouble (I'm not sure what)
- The mod makes an already not very environmentally friendly engine less friendly.

I've been curious about this, and haven't looked at my intake after 64K, but will soon. It seems good fuel, not babying the engine, and cleaning the intake periodically (every 50K, perhaps?) is a better solution.

Comments?
 

LWB053

Vendor
Joined
Aug 5, 2003
Location
Tampa, FLA, USA
TDI
2000 Jetta, Dk Green
Basically, here's what happens...

In a completely stock car, the EGR system allows some burnt exhaust gas to be re-introduced into the intake under certain operating conditions. The purpose of this is to reduce the amount of oxygen available for combustion. By reducing the amount of oxygen, you reduce exhaust gas temperature, and you reduce the formation of NOx.

A couple of downsides to this...the hot gas (and it's still quite hot, even though it goes through a 'cooler') is re-introduced at a point in the intake where the intake bends down to feed the cylinders, and the intake probably has some amount of oil in it from the crank case vent (CCV). This causes the oil to get 'baked on' to an already somewhat restriced air flow path...eventually causing some degree of blockage.

Another downside to this, for the performance minded...displacing oxygen in the cylinders reduces the amount of fuel that can be efficiently turned into power. Also, when the EGR cycles open, less exhaust is available to turn the turbo, resulting in a slight reduction in available boost.

Now, some have found that you can use a VAG-Com to modify the EGR system...it's still within VW specs, but it cycles open less often. Some people who have done this have found that low-end power declined over time...most weren't even aware of the power decline until they reset the EGR back to mid-band (where it's set from the factory). But after setting the EGR system back to stock values, they've commented on the "new found power" their cars had.

Others have simply eliminated the EGR all together...by either blanking off the vacuum lines that open it, or by closing the line that allows the gas to enter the intake. Typically, you can expect a check engine light from this, since the ECU expects there to be a response to its commands for EGR operation.

There have been several cases where people have reduced or eliminated the EGR, and still reported clogged intakes.

Also, bear in mind that the EGR is put in place as a "pollution control device", and therefore, any tampering with it outside factory specifications on a road vehicle in North America can considered illegal. I think there is some debate over whether using the VAG-Com to modify it is illegal, since the VAG-Com can only modify it within certain values allowed by VW.

Keith
 

G60ING

Top Post Dawg
Joined
Aug 5, 2001
Location
MD
TDI
No TDIs Currently, I have an R36 Corrado. I've had an ALH Corrado swap, AHU Corrado swap and 2003 TDI Jetta
after 101K miles the buildup was surprising on my 2003. I had the duty cycle turned down at 15K miles and I drive it HARD everytime I get the car out of the wife's hands which is more then once a week.




 

Fortuna Wolf

Veteran Member
Joined
Apr 28, 2006
Location
Wilmington, NC
TDI
2002 Jetta TDI Auto Sedan
Oh wow, nice. That was with the EGR mod?

So the current theory is that the best solution is to install a CCV oil filter?

If I did that, could I increase the EGR to reduce emissions without a problem?
 

spoilsport

Top Post Dawg
Joined
Oct 3, 1999
Location
Houston TX
TDI
2000 Golf GLS Silver (Sold). 2005 Jetta TDI Wagon Tiptronic (daughter's)
What about ULSD?

How does the advent of ULSD figure in to the IM clogging equation?

Will it help? A little, or a lot? :confused:
 

G60ING

Top Post Dawg
Joined
Aug 5, 2001
Location
MD
TDI
No TDIs Currently, I have an R36 Corrado. I've had an ALH Corrado swap, AHU Corrado swap and 2003 TDI Jetta
Fortuna Wolf said:
Oh wow, nice. That was with the EGR mod?

So the current theory is that the best solution is to install a CCV oil filter?

If I did that, could I increase the EGR to reduce emissions without a problem?
G60ING said:
after 101K miles the buildup was surprising on my 2003. I had the duty cycle turned down at 15K miles and I drive it HARD everytime I get the car out of the wife's hands which is more then once a week.
See my original post
 
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tditom

Top Post Dawg
Joined
Sep 5, 2001
Location
Jackson, MI
TDI
formerly: 2001 Golf GL, '97 Passat (RIP) '98 NB, '05 B5 sedan
spoilsport said:
How does the advent of ULSD figure in to the IM clogging equation?
I think that less sulphur = less soot.

Will it help? A little, or a lot? :confused:
theoretically, yes. Dunno how much...
 

tditom

Top Post Dawg
Joined
Sep 5, 2001
Location
Jackson, MI
TDI
formerly: 2001 Golf GL, '97 Passat (RIP) '98 NB, '05 B5 sedan
G60ING- What kind of fuel and oil do you use? TIA
 

G60ING

Top Post Dawg
Joined
Aug 5, 2001
Location
MD
TDI
No TDIs Currently, I have an R36 Corrado. I've had an ALH Corrado swap, AHU Corrado swap and 2003 TDI Jetta
I use genaric diesel fuel and Shell's Rotella T 5w-40.

 
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dieseldorf

Top Post Dawg
Joined
Oct 11, 2000
Location
MA
TDI
ex- 1996 wagon, ex-2000 Jetta
G60, it's hard to say the accumulation is "bad" (for your local area) without having any other data point.

I dunno, we've seen occlusion like that at less than 40k miles. How excited can you get about it?

In general, using a low NOACK oil and ULSD IS going to help this build-up problem.
 

G60ING

Top Post Dawg
Joined
Aug 5, 2001
Location
MD
TDI
No TDIs Currently, I have an R36 Corrado. I've had an ALH Corrado swap, AHU Corrado swap and 2003 TDI Jetta
dieseldorf said:
How excited can you get about it?
I have no intentions of changing what I'm cuurrently doing with the exception that I have put the duty cycle back to the OEM setting to see what it looks like at 150K miles.

dieseldorf said:
There is no choice on this now that the new regs have hit and the station where I fill up has made the change.
 

spoilsport

Top Post Dawg
Joined
Oct 3, 1999
Location
Houston TX
TDI
2000 Golf GLS Silver (Sold). 2005 Jetta TDI Wagon Tiptronic (daughter's)
why restored power with default egr setting?

Could someone explain, at least in theory, why after dialing the EGR back to default OEM, some get a restoration of power? :confused:


Is it because there is still some potential energy to burn in the exhaust fumes, and that offsets the negatives?
 

dan TDI on jet-A

New member
Joined
Sep 28, 2009
Location
canada
TDI
2002 golf tdi
Egr

My EGR valve is opening and closing will driving. cousing my boost to jump when the EGR opens, no codes on vagcom. will do it with EGR mod in our out. any ideas ?
 
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