Anyone reactivate EGR for better mpg?

truman

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I have an SRP and an inactive egr+ RC2 and b203s. I average about 42mpg in my '03 JW-5M. I was wondering if anyone has had an improvement in FE by reverting back to standard egr operation? Now that we have ULSD, I assume intake clogging is no longer an issue.
 

silverbox

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Truman I have an 03 JW 5 speed as well. I average 46mpg with an alligator tune and EGR on...I am thinking of getting thr EGR delete for better economy.
Maybe I'm wrong
 

dieseldorf

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truman said:
I have an SRP and an inactive egr+ RC2 and b203s. I average about 42mpg in my '03 JW-5M. I was wondering if anyone has had an improvement in FE by reverting back to standard egr operation? Now that we have ULSD, I assume intake clogging is no longer an issue.
T, you may find a slight improvement in economy with the EGR returned to operation. However, the new S15 fuel will not completely elimate the clogging issues, but should dramatically slow it. Personally, I wouldn't fool with it. Leave things as-is and you won't have to worry about cleaning the IM again.
 

truman

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I think you are right DD, I'm probably better off leaving well enough alone. The other factor that I did not mention is 16" Octopus rims which seem to rather heavy and non-LRR tires. Performance comes at a price.
 

mrGutWrench

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dieseldorf said:
(snip) Personally, I wouldn't fool with it. Leave things as-is and you won't have to worry about cleaning the IM again.
__. Yeah, but on the subject of the fuel economy effects of EGR, it seems to be that it's something to do with the "feedback" of the engine ECM. If the engine ECM sees the EGR working, it seems to vary fueling so that the MPG is increased. Too bad there's not some way to stop the EGR going into the engine but keep the ECM offset that increases MPG.

__. My guess is that this could be done by changing the output of whatever analyzes the amount of EGR (thus fooling the ECM externally) or by software changes in the ECM (e.g. "chip") but I don't have the slightest idea of how to do this in practice.
 

2slowtdi

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I don't know mine mpg stayed about the same.
But my usable rpm range went up.
 

truman

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Maybe just for grins, I'll swap egr valves for a few tanks and see what happens. I have an SRP in it now and a spare valve on the shelf. If there is no appreciable difference, then the SRP goes back in.
 

wjdell

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Looking at the book its a bit of hardware - out here in the stix we have no epa test. What would be the benefits of complete removal - blocking plates are easy to make.

Less soot in the oil, less wear, cleaner upper piston, rings,valves, manifold and heat in the engine compartment.

but what would be the negative effects -
 

PDJetta

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My PD gets the same mileage, after the EGR system somehow got plugged up:D . But the throttle plate mysteriously disapeared at the same time, and this may have something to do with the lack of economy loss.

At least on the PDs, the throttle plate (its electrically driven by a motor, not vacuum, on the PDs) actuates when EGR is called for by the ECU to suck more exhaust into the intake manifold. If the EGR pipe gets blocked by some foreign "object", without the throttle removed, a vacuum will occurr in the intake as the throttle closes when EGR flow is called for. This vacuum will cause a pumping loss and an effeciency hit.

--Nate
 

Suns_PSD

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But Nate, wouldn't the EGR delete prevent the butterfly valve from closing at all through the custom programming?

Either way, my butterfly valve must have also fallen out when I had the intake apart for cleaning!
 

PDJetta

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"But Nate, wouldn't the EGR delete prevent the butterfly valve from closing at all through the custom programming?"

That's what I'm hoping. I plan to ask the chiptuner in person at a future TDI Fest!

Yea, my throttle plate somehow fell out of the intake, right about the same time my EGR pipe got mysteriously blocked with some foreign object:confused:

Where I drive, there is HEAVY traffic and I do lots of idling (stuck in traffic, but can't turn the motor off because traffic inches forward within a minute or less), creeping and light load operation. This type of driving causes the highest exhaust recirculation flow rates in a TDI. Not good at all!

I just don't like the idea of not having the throttle plate to choke off the air when the key is turned off. You could conceiveably loose an engine because of it. I think my clutch is beginning to slip some too. A run-away engine and a slipping clutch are a recipeit for disaster!

I've been studying the wiring diagram for the throttle plate motor and I plan on trying to figure out how ti apply power to the correct terminals to get it to shut fully and then open when the power is turned off. The plate/motor is spring loaded, so if the system failes in operation, the plate stays open to prevent the engine from stalling, a potentially dangerous situation on the road. I may be to work this to an advantage. Plate stays open w/ no power applied and with 12V to the correct terminals, the plate closes. You could just hit the "closed" switch you install on the dashboard to close the plate and kill the motor, if a "runaway" occurrs. The 12 volts would be supplied even when the key is "Off". Then, after the engine stops, you just flip the switch "open"

With normal operation, the throttle plate closes when the key is turned off (for a quiet engine shut down) and then opens a few seconds later, ready for the next enguine start. I want to figure out how that works too.

And, under normal operation, with the engine running, the throttle plate is locked open (you can not push it closed with your fingers), but if you unplug the electrical connector to the throttle plate motor, you can manually close the plate against its spring tension, I belive. Let go of the plate, it springs back open.

--Nate
 
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truman

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It's interesting that my initial perspective on swapping back to an operational egr is that it appears that FE may be better- should have a little better idea next week.
 

therod

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I cleaned my intake a while back when my car turned 100,000 miles and did not want to go through that again so I did the VAG-COM adaptation to the egr and also the golf tee mod (got the CEL.:mad:) I ran a few tanks through it and found my fuelk economy was down from an average of 46 mpg to 43 mpg. I thought it was strange cause I thought the cleaner intake (It was about half clogged) would help fuel economy. I decided to see if plugging the vacum hose back into the egr and keeping the VAG adaptation would produce any different results. My fuel economy on my next 3 tanks have been 47, 48, and 47, mpg respectively. could the egr give a 4 to 5 mpg increase when its working vs when it is disabled? Or might I have another problem that might be enhanced by disconnecting the egr (maybe a clogged cat or something)?
 

jollyGreenGiant

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VAG-COM adaptation for EGR plays with things like IQ and timing along with EGR, I never had any luck with reduced EGR adaptation, it effected too many other things for my liking and I too received a 3-4 mpg drop in mileage with it adapted on it's lowest setting along with a similar drop in torque. There's better ways to handle the EGR than through the adaptation method on the rotary pump TDI's IMO.
 

unL33T

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Hmm... maybe this is why my econonmy seems slightly lower than the average. I had the VAG-COM modification done very early after I got the car.

I was going to do a complete EGR delete because I plan to swap in a PD130 intake manifold and I hear my old EGR won't bolt up it... maybe I'll have to look into that more.
 

Brock_from_WI

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I noticed the same thing when I set my EGR back to normal, a bit more power, quicker warm-ups in winter and 3-4 gain in mpg's. I had a suspicion it was altering more then just the EGR.
 

SoCalC

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jollyGreenGiant said:
VAG-COM adaptation for EGR plays with things like IQ and timing along with EGR, I never had any luck with reduced EGR adaptation, it effected too many other things for my liking and I too received a 3-4 mpg drop in mileage with it adapted on it's lowest setting along with a similar drop in torque. There's better ways to handle the EGR than through the adaptation method on the rotary pump TDI's IMO.
What are your thoughts on the better ways, if you care to speak publicly on it? ;)

BTW, the car is doing well. It has about 102K on it. A few issues but always reliable. One of the nerds at work is jealous of it. Of course he's looking into the Mercedes options.
 

jollyGreenGiant

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Well, I haven't personally gone through collecting data, graphing it all out and proving it scientifically but I do believe with the EGR turned down, the injection timing is similalrly retarded and thus loss of efficiency but less NOx, so it's a trade off, intakes will always have some clogging and the best case scenario is to drive it hard, don't be afraid of higher revs, use quality fuel, blah , blah BUT the key is to check it every 20-40K and clean it when it needs it. It's that simple, I know it's a PITA but almost everyone says wow I should have done that sooner after it's done.

I think fuel and probably boost map to a lesser degree probably also change but the two big ones are EGR application and injection advance.

The best solution is to talk with a tuner that understands your needs and can tune it accordingly. The recomended tuners around here all have something that can take care of it without setting a CEL. I can't offer too much else on that.

Glad the car is doing well, I wish I still had it!
 

Thermo1223

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Wow, I did notice the car sucking down more fuel with adaptation, maybe I should put it back to stock even though the EGR is plugged up.

EGR Delete Kit FTW!!

I would change one thing about the kit though, not need to replace the molded coolant hoses with a straight like, just get an inline coupler.
 

Tom109

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Interesting thread, as I'm now seeing better FE with the golf tee.

I had the adaptation done at 3k miles from new on my 2003 wagon. Steady 53mpg on a stock motor for 2-3 years, then my commute chaged to 20 miles rural driving. MPG dropped to 47mpg. I started investigating when long highway trips (round trip NJ/Chicago) remained at 47mpg. Currently I'm back up to 50mpg, on the same rural commute with the golf tee and no CEL.

I still think there might be another (minor?) tuning problem to be found, but it drives much better (freer revving, better feel) and the mpg's are back. I don't have an explanation??? I've never cleaned the intake in 90k miles, so that is next as soon as I find the time...

Regards,

Tom P.
2003 Jetta Wagon
 

dieseldorf

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JGG, if we leave the EGR set at default, and simply un-plug/T off the vac line to the EGR, do you think the computer still retards the timing resulting in lower MPG, power, etc? Blocking plate have the same effect?

(I suspect the MAFS is looking for that corresponding flow deviation when the EGR is supposed to open, yet it doesn't occur leading to the ECU taking corrective actions?)
 

jollyGreenGiant

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CEL's aside, default EGR adaptation with a plugged or blocked EGR will have the "normal" mapping. Only when backing down the adaptation will the retarding effect map be used. The VE rotary pumped engines don't; as I understand it, detect low EGR flow and subsequently back off injection advance, fuel quantity or any other control based on detected flow alone. Of course I could be totally wrong, but that's what I believe to be happening. So, best case scenario ( for off road purposes of course ) is to have the EGR blocked or otherwise rendered incapable of injecting exhuast gas back into the intake and the adaptation to the default or perhaps even higher ( more advance following the same line of thought?? ).

( Be forewarned ) I'm not going to stand by my theory under close scrutiny because it's just that, only a theory. I'm unable to prove it with the information that I have, I suppose one could log lot's of data and draw a firm(er) conclusion but it won't be me...
 

Honeydew

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After reading this thread I just changed the egr adaptation value back to stock. Since changing it from stock I've made the SRP and installed an egr cooler delete kit and aligator tune. Therefore the adaptation is no longer needed. I will report any changes in mileage, etc.
 

jollyGreenGiant

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After reading this thread I just changed the egr adaptation value back to stock. Since changing it from stock I've made the SRP and installed an egr cooler delete kit and aligator tune. Therefore the adaptation is no longer needed. I will report any changes in mileage, etc.
Please do, hopefully you have a repeatable schedule so you can compare a few tanks now to what you were getting. Do you have good mileage records just prior to the changes as noted above?
 

Honeydew

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jollyGreenGiant said:
Please do, hopefully you have a repeatable schedule so you can compare a few tanks now to what you were getting. Do you have good mileage records just prior to the changes as noted above?
Typically calculated mileage has been 37.x mpgs and if fairly repeatable. I also have SGII and can make more anectdotal comparisons from that. Nothing else will change on the car for a few weeks so I should have meaningful data.
 

Thermo1223

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Maybe tomorrow I will log fuel consumption with the same trip distance just to see if there is an immediate difference in fuel economy.

One with adaptation and without, I am particually interested to the see the effects on a cold engine. How it affects timing and such.
 

therod

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I had a stage 1 kerma tune installed recently. The tune disabled the idiot light that comes on when you unplug the egr. I still had the egr adaptation mod done. I was getting 45 mpg solid through 3 tanks. I decided to set the egr adaptation back to stock since it was not needed since I had disabled the egr valve completely. I saw an immediate gain in my fuel economy by 3 mpg. I am half way down on my second tank and it is looking good so far.
 

Honeydew

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My first tank after setting the adaptation back to default was 40 mpg (calculated, filled to neck). The best tank recorded with the mod value over the last 13 months was 37.8 mpg and was typically in the low 37s.
 
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