Anyone reactivate EGR for better mpg?

So this is were my mileage has been going. I had Pete (DBW) adjust my EGR last summer and mileage has been off slightly but I was blaming ULSD.
Think it's time to re-set EGR and just pull the intake for a cleaning.
Mike

I'm curious to hear more folks return the adaptation back to default and report back after a few tanks.

This old thread focuses on this topic. Elsewhere I have read cage claim 5-9 mpg better with default setting but failed to locate that one.
http://forums.tdiclub.com/showthread.php?t=67507

Well this was my first tank w/ egr set back to 32768. My numbers are very consistant- 43.5-44. This tank was 47 on the nose. It's been a couple of years since I have seen 47. This was not an all highway run either. The best previous that I have seen on an all highway run was 45. I have no doubt that 50 is doable once again if I kept it below 70. My 16" WRs are holding me back a little bit also.

I'm running an aligator tune with erg functioning i just reset the erg to the stock value...feels different i'll report back on milage in a few weeks.
So far it feels better around town.

silverbox said:

I'm running an aligator tune with erg functioning i just reset the erg to the stock value...feels different i'll report back on milage in a few weeks.
So far it feels better around town.

Click to expand...

.

My seat of the pants opinion is that low end torque is significantly improved with fully functioning egr. When I removed the SRP, I noticed that my 658 gear seemed to pull better and more smoothly below 60mph. There has been additional improvement with the stock egr setting. I am very pleasantly surprised by the increased FE as well. I may have to do a FE run for a tank soon and find out if I can revisit the 50mpg barrier that I haven't come close to breaking in over 2yrs. I thought that I should be doing better despite RC2, 216s, and bigger, stickier tires. I'm sure that I have found an answer. The variation in my mileage numbers has been nil. My car likes a fully functioning egr.

Any data on PD engines? After my 2002 choked to death (didn't find the club until after the turbo was also gored), I found the 2006 PD to be significantly peppier, but it delivers 42 from the first logbook entry vs. 47 for the 2002. I run 75 miles round trips daily, mostly around 65, 2000 ft down the mountain in the mornings, and 2000 ft up in the evenings. The pipes get blown clean daily, so to speak, but it didn't save the first Jetta (diesel commuter #5). I'm at 26K so far on the 2006, sounds like it's time to pull the intake for a look, I'd like to maximise the benefits from that (literally) pain in the back. Milage is the goal, tailpipe is not an issue. BTW, the low-end on the PD sucks - from day one, if I forget what I'm driving (the other driver is a 7.1L turbo diesel pickup - pop the clutch and it idles up a 22 pct grade), it stalls away from a light on a grade when the AC is running.

dj_check said:

Any data on PD engines?

Click to expand...

For this discussion, the PD engine doesn't remain in context as it's EGR can't be adapted via VAG-COM.

FWIW though I've looked down the intake of many PD's several of which have over 100K without any intake attention and there is hardly any buildup whatsoever. The intake buildup phenomenon is limited to the VE ( pre PD ) variety TDI's. Sure it can happen in a PD but not under normal use or normal engine condition.

BTW: Regarding the PD low RPM torque issue, get a tune on it ( my PD chip tuning experience is with Rocketchip and wholeheartedly give my thumbs up ) and it'll put a huge smile on your face, it's amazing what a proper chip tune does to the PD engines, you'll thank me I gaurantee it.

I've been curious about my FE after the EGR delete. It seems to have dropped my mileage down too. I've been thinking I should get it switched back on to see what mileage per gallon I get. I'm currently getting about 37.5 mpg which isn't too impressive. Then again, I drive like I have a flame under my @ss

I do not see how exhaust gas can get better FE than fresh air.
If you do a Vag-Com on IQ have you not bypassed the remapping of the
ECM when resetting to off road EGR numbers?

2slowtdi said:

I do not see how exhaust gas can get better FE than fresh air.

Click to expand...

It is the changing of ECU/ECM values via the EGR adaptation that effect fuel economy rather than the amount of exhaust gas into the intake. The EGR system on my car has been replaced with block-off plates. Changing the EGR adaptation value back to stock with the same physical setup has resulted in better FE and seemingly increased driveability. No exhaust gas gets into the intake with either setting.

If you do a Vag-Com on IQ have you not bypassed the remapping of the
ECM when resetting to off road EGR numbers?

Click to expand...

Others have reported changes in IQ values correlated to various EGR adaptation settings. I haven't checked mine since going back to the stock setting.

After about a week of driving the stock EGR setting, I can say the car feels much better any time I'm crusing with low RPM...1500 to 2000.It also has less smoke I'l keep an eye on the milage and post again, so far it hasn't hurt.

Honeydew said:

It is the changing of ECU/ECM values via the EGR adaptation that effect fuel economy rather than the amount of exhaust gas into the intake. The EGR system on my car has been replaced with block-off plates. Changing the EGR adaptation value back to stock with the same physical setup has resulted in better FE and seemingly increased driveability. No exhaust gas gets into the intake with either setting.

Others have reported changes in IQ values correlated to various EGR adaptation settings. I haven't checked mine since going back to the stock setting.

Click to expand...

Interesting point, after I have run mine for awhile with functioning egr and stock settings, I may try the golf tee mod for FE comparison and later consider reinstalling the SRP. In the end, trying to outwit VW engineers is not without some negative consequences.

Ok I understand, blocked off egr and oem setting, maybe better for mpgs.

I have done the WingNut mod on the egr and have a new egr set
next to my cabin air filter with the vacuum line on it, and the off road
setting to keep the MIL from coming on.

I have just had my timing belt done and set the IQ with Vag-Com and
I'm getting 40 to 41mpg's in town and 49 to 52 mpg hwy slower the
better 50mpg at 75mph.

Before the timing belt I was getting 38 intown and 47 mpg hwy
we did have the timing set to the limit.

So if setting the egr numbers back to stock and keeping the higher RPM by not having a working egr there, that would be great.

here is a quick update on my mileage. As noted previously, no tank with egr "turn-off" adaptation over the course of 13 months yielded mpg better than high 37.X. Three tanks now have all clocked in at 40.0-40.1 mpg. Going back to stock setting appears to have boosted my mileage by 2-3 mpg.

I suspect that when the egr is active it lets air from the egr valve back into the engine, this causes the MAF to read lower airflow causing less fuel to be injected. However it shouldn't make a difference in full throttle power as the egr is then disabled by the ecu.

As another viewpoint, my Grand Vitara loses about 2mpg with EGR enabled, boost spike is more pronounced too.

Said HDI engine *does* however close the antishudder valve as a throttle when EGR is requested...

TDIFanatic1.9 said:

I suspect that when the egr is active it lets air from the egr valve back into the engine, this causes the MAF to read lower airflow causing less fuel to be injected. However it shouldn't make a difference in full throttle power as the egr is then disabled by the ecu.

Click to expand...

Yes, this is correct. The ECM monitors EGR functionality by the reduction in MAF readings when it raises duty cycle to the EGR solenoid. When the ECM is calling for EGR and the MAF doesn't reduce it's reading, then the ECM flags that as a malfuncitoning EGR system and thus a CEL. This of course varys by model year and ECM tuning...

The adaptation method this thread is discussing backs down; through a multiplier effect, the duty cycle but carrys with it some side effects, those being reduced injection advance and other efficiency reducing mapped controls such as fuel delivery and perhaps even boost for all I know. Bottom line is that the adaptation isn't all that it's cracked up to be, it's taken some a lot longer than others to catch on to this. There are better ways to handle the rediculous levels of EGR application coupled with the poorly designed airways supporting the EGR gas introduction into the combustion chamber in pre PD engines.

If your adaptation channel 03 is lower than 32768, then you're loosing performance and efficiency for little gain IMO.

jollyGreenGiant said:

There are better ways to handle the rediculous levels of EGR application coupled with the poorly designed airways supporting the EGR gas introduction into the combustion chamber in pre PD engines.

If your adaptation channel 03 is lower than 32768, then you're loosing performance and efficiency for little gain IMO.

Click to expand...

What are some better ways, specifically? I've had the egr adaptation since the last IM cleaning (40k miles ago), and am a few mpg's lower than where I should be. I don't want to un-adapt until I know a good way to keep the intake clean.

I changed everything back this weekend and now the turbo lag that I was strugling with for so long is almost gone. The car feels much more punchy again especialy at low rpm. I'm glad I found this thread. WOW the power is so much smoother.

Filled up the tank 1057 km 50/50 city and highway use this was a bit over 50mpg (us gal) This seems like better FE by a bit, 2 mpg or so, with the EGR set to stock. But the big difference is the way the car feels.. much smoother and more powerful under 3000 rpm. I'll keep checking for the next few tanks.

Just another data point here -- keep in mind that I am not nearly the car buff most all of you are, but I do really like my TDI. And I struggle a bit with all the acronyms, but here goes. I had to have the IM augered out at 40,000. This is when I joined the TDIclub and learned about the EGR. I had a fellow member reset the EGR to the minimum. So far no problems, but I'm at the danger point -- another 40,000. Anyway, I observed about a 3 mpg drop in FE beginning at about the time of the EGR reset. Now I am reading here that the ULSD may solve, or mitigate the IM clogging and returning to factory EGR setting may be recommended. I sure would like to get back to the 50mpg I used to get, but hate to think about $300 for IM cleaning again. I will stay tuned for a consensus here on this issue.

BTW, I am pretty sure closing the EGR is not particularly legal and the local mechanic won't do it, correct? I don't really want to blow pollutants out the tail pipe, but wonder if the ULSD solves this problem anyway? How hard is it for a backyard mechanic to close the EGR? Thanks!

Honeydew said:

Others have reported changes in IQ values correlated to various EGR adaptation settings. I haven't checked mine since going back to the stock setting.

Click to expand...

Today I checked the Injected Quantity (IQ). With the 33768 I had had the IQ set to 2.4. Today, with the EGR set back to stock 32768 the IQ was reading 1.4 at the same setting. I adjusted the IQ to bring it back to 2.4 and also manually advanced the retarded timing to the top of the graph.

my 02 wagon has an RC2 tune with egt delete...

can i turn the egt back on thru the adaption process or do i have to call jeff and have him reprogram.

before my tune my best mpg was in the 45 range...on winter blend...now with the tune the best i have been able to get is in the 41-42 range driving at 65.....

wonder if the egt delete is the culprit now!!

grandpa's TDI said:

my 02 wagon has an RC2 tune with egt delete...

can i turn the egt back on thru the adaption process or do i have to call jeff and have him reprogram.

before my tune my best mpg was in the 45 range...on winter blend...now with the tune the best i have been able to get is in the 41-42 range driving at 65.....

wonder if the egt delete is the culprit now!!

Click to expand...

I suggest you call Jeff and see what he says about it. The vag-com stock value should be 32768. I think the tuners use a different egr delete method. Please post what you find out.

FWIW - my mileage went up when I deleted my EGR, however I did a lot of other mods at the same time. This setup netted me my best mileage ever.

EGR Delete (cooler and valve)
Race Pipe Installed
3" downpipe & 4" exhaust installed
PP502's installed
RC2 installed

Probably not exactly relevant, but on topic

After much reading it would seem that stock TDI's will get better mpg's
with the egr on.

TDI's that are shall we say not stock, bigger this and that get better
with out the egr working as it adds more fresh air to more fuel.

I don't know if just a chip will fall in this but I would think so as it
gives more fuel and boost.

This thread has been primarily about the adaption channel 03 "EGR" and its effects on mileage, performance and intake buildup.

2slowtdi said:

After much reading it would seem that stock TDI's will get better mpg's
with the egr on.

TDI's that are shall we say not stock, bigger this and that get better
with out the egr working as it adds more fresh air to more fuel.

I don't know if just a chip will fall in this but I would think so as it
gives more fuel and boost.

Click to expand...

On my 2003 this is the conclusion I have come to and I have had Vag-com
within weeks of getting my TDI and tried most setting from stock to off road for the first two years.
After that it was no longer stock.

Hey FixUB,
You didn't mention what setting value you have for EGR, stock: 32768, or something else? Also, what kind of mpg do you get?