EGR Delete causes cel

I have a 2001 jetta 1.9 tdi mkiv alh 5 speed std. I found a video of an egr delete with a race pipe. I have done a “home made” egr delete of the cooler and piping and simply made a cap plate for the egr at the “throttle body” and turbo, and rerouted the coolant lines. This would emulate installing a “slightly restricted” race pipe but keep the anti shudder valve operational. This format causes a cel with code 17965 overboost and 19586 egr. I removed my cap under the “throttle body” egr valve, put my fingers under the egr with the engine running and found intake air escaping at idle, and no air escaping when throttle is “snapped” or when the vacuum line to egr is removed. With the plate removed I do not generate a cel, however leaving this plate off/open does present some “spray” of fuel residue down the back of the engine, so my cap must stay installed.

I can’t find any “overview” of the egr system with bentley or on-line, and I am having some difficulty understanding the working of the egr system. It would seem that the egr system also seems to be used to regulate the MAP of the intake in allowing some reverse flow back towards the exhaust egr cooler when vacuum is applied to the egr, and no "back flow" when vacuum is removed either by pulling the hose off the egr or during "snap" of the throttle when intake vacuum drops. I am reasonably new to TDI’s, but on most (older) gasoline egr systems, the egr is not operated until the engine has reached operating temperature. This does not seem to be the case with TDI’s. TDI’s seem to use the egr flow to aid in engine warm up, so the egr operates/is available, right from start-up.



My engine obviously has more power (boost) with my cap plate installed, which “feels” great. The constant cel “sucks”. I have been "surfing" sites for days now, and I can find lots of information right up until I have generated a cel .....so my questions would be:

• Does the increased “boost” at “all times” caused by my egr delete, cause any concerns with normal day to day driving?
• If not, what is the easiest way to not show a cel? (other than black tape over the light, LOL). I do not have a VAGCOM but am willing to purchase.
• Do you know of any source (online) that could show me an “overview” of the egr system so I can determine what the engineers are trying to accomplish and how they are monitering the system so I can figure out how to "fool" it.
• Does my ecm need to be “adjusted” or “tuned” to accept "or be fooled into accepting" the egr delete I have installed and if so, any suggestions on who or where? Is this “tune” doable with VAGCOM.

I realize that I have opened the door to responses from many enthusiasts who firmly believe in the environmental implications of removing any device which will save our ozone however, someone designed these TDI gems to operate and provide hp ... and then "backed them off" with an egr system to accomodate environmental requirements. I personally prefer hp, driveability and maintainance, with the least amount of complications. Any help in the latter would be greatly appreciated.

Deleting Federally mandated emission equipment is a crime that carries some stiff penalties if you get caught.

However, the only way to turn off the CEL is with a chip tune.

...and because it's a federally mandated emission control system the ECU tests its operation carefully and regularly, under dynamic operating conditions, to make sure it exists and is functioning properly.

Hence the CEL, hence no way to mask the system with a resistor etc etc etc, and you can't use VCDS to bypass it either.

Surprised your searching didn't turn any of this up... it's an oft-discussed topic.

Huh? Your rambling. The CEL can be tuned out. Although technically illegal, there are chip tuners that will do it.

Ol'Rattler said:

Huh? Your rambling.

Click to expand...

I normally don't respond to rudeness, but for the sake of future searchers: what I said was there is no way to fool it with a resistor or tune it out with VCDS.... both of which I believe to be the case.

I guess the OP didn't do enough searching..

EGR disabled=CEL
Retuning=no CEL

Gosh, everyone has to make this system into a big deal! What a useless topic.

Thank you guys. I understand and appreciate the "chip" and I will look further into it.
How the egr actually operates is both interesting and confusing to me and I was hoping for some information up that avenue. I have determined by un-capping the underside port of the egr and covering with my fingers only, that the egr seems to operate as a pressure relief in the intake/boost system in that at idle it actually bleeds out intake air pressure from the intercooler back thru the egr cooler towards the exhaust manifold and turbo thus reducing/controling boost pressue at times when engine vacuum and intake pressure is high. When I capped/plated the underside port of the egr ...this is when the ecm produces an overboost code and egr code (likely as determined by the MAP sensor). When heavy throttle is applied under load and vacuum drops in the hose to the egr, the egr closes...so....how does exhaust gas (and at what point in engine operation) enter the intake and fill the intake with soot? Does exhaust pressure somehow overcome intake pressure at some point?

Faberktor said:

I have a 2001 jetta 1.9 tdi mkiv alh 5 speed std. I found a video of an egr delete with a race pipe. I have done a “home made” egr delete of the cooler and piping and simply made a cap plate for the egr at the “throttle body” and turbo, and rerouted the coolant lines. This would emulate installing a “slightly restricted” race pipe but keep the anti shudder valve operational. This format causes a cel with code 17965 overboost and 19586 egr. I removed my cap under the “throttle body” egr valve, put my fingers under the egr with the engine running and found intake air escaping at idle, and no air escaping when throttle is “snapped” or when the vacuum line to egr is removed. A boost leak caused when the ECU calls for some EGR. With the plate removed I do not generate a cel, I guess the boost leak simulates the drop in air flow the ECU expects when the exhaust displaces some of the intake air however leaving this plate off/open does present some “spray” of fuel residue no fuel in the intake, it's oil from the CCV down the back of the engine, so my cap must stay installed.

I can’t find any “overview” of the egr system with bentley or on-line, and I am having some difficulty understanding the working of the egr system. It would seem that the egr system also seems to be used to regulate the MAP of the intake in allowing some reverse flow back towards the exhaust egr cooler when vacuum is applied to the egr, and no "back flow" when vacuum is removed either by pulling the hose off the egr or during "snap" of the throttle when intake vacuum drops. I am reasonably new to TDI’s, but on most (older) gasoline egr systems, the egr is not operated until the engine has reached operating temperature. This does not seem to be the case with TDI’s. TDI’s seem to use the egr flow to aid in engine warm up, so the egr operates/is available, right from start-up. Exhaust pressure is higher than intake so flow is into the intake when EGR valve opens. It in no way functions as a manifold pressure regulator.



My engine obviously has more power (boost) with my cap plate installed, which “feels” great. The constant cel “sucks”. I have been "surfing" sites for days now, and I can find lots of information right up until I have generated a cel .....so my questions would be:

• Does the increased “boost” at “all times” caused by my egr delete, cause any concerns with normal day to day driving? You aren't getting increased boost. Manifold pressure is set by the ECU by regulating the turbocharger.
  
• If not, what is the easiest way to not show a cel? (other than black tape over the light, LOL). I do not have a VAGCOM but am willing to purchase.
• Do you know of any source (online) that could show me an “overview” of the egr system so I can determine what the engineers are trying to accomplish and how they are monitering the system so I can figure out how to "fool" it. It simply adds some exhaust to decrease combustion temp. From your testing that doesn't simulate real conditions you have come up with some false assumptions on what it does.
  
• Does my ecm need to be “adjusted” or “tuned” to accept "or be fooled into accepting" the egr delete I have installed and if so, any suggestions on who or where? Is this “tune” doable with VAGCOM.

I realize that I have opened the door to responses from many enthusiasts who firmly believe in the environmental implications of removing any device which will save our ozone however, someone designed these TDI gems to operate and provide hp ... and then "backed them off" with an egr system to accomodate environmental requirements. I personally prefer hp, driveability and maintainance, with the least amount of complications. Any help in the latter would be greatly appreciated.

Click to expand...

I don't think there's any power to be gained here. I don't believe the EGR valve opens at full power, but I could be wrong. The only advantage is not recirculating soot back into the intake.

why not just put egr back on,& turn it down to minimum with vcds? with your alh you shouldnt be getting any EML light.i think you have other problems.check all vacuum hoses & pipes for holes etc.
why did you do all that to your engine/egr anyway?

The only rational reason to block the EGR on an ALH is to stop the intake from clogging and thus requiring cleaning. However:

1. The cleaning is required on much longer intervals since ULSD showed up (but still does sometimes, with some engines, have to be done -- like mine, for instance, which did.)

2. If you remove (or block off) the EGR (a) it is illegal, (b) you will throw a code, (c) if you tune out the code with a chiptune it's still illegal and (d) if your jurisdiction requires emission testing the car will fail readiness and you'll have to put it back to pass. Even if (d) isn't true today it might be tomorrow and now you get to put it back. Oh, and if you sell the car with it deleted the buyer will get pissed if he moves to or lives in a jurisdiction that requires testing and he may rat you out at which point you could have some serious problems.

Vince Waldon said:

I normally don't respond to rudeness, but for the sake of future searchers: what I said was there is no way to fool it with a resistor or tune it out with VCDS.... both of which I believe to be the case.

Click to expand...

Not trying to be rude, just want to understand your ramblings. What does a resistor or VCDS have to do with the OP's post? The only way to get rid of the CEL is to tune it out. That may have been what you meant, but that's not what you said.

What does etc etc etc mean? Don't leave us guessing on the intent of your words.

It should be noted that you can 'turn down' the EGR requested flow via VCDS. I've done this on multiple '00 and '01's and never, not once, received a CEL. However, on my '02, the adjustment in VCDS did not eliminate the CEL and it came back rather quickly.

Essentially, find someone with VCDS, adjust the value as it hints (raising the number lowers the requested flow,) delete your current CEL, and see if it comes back. If not, drive happy. If it does, tune it out.