tylertitus14

I want to remove the EGR valve on my 96 12 valve A4 and block off the intake manifold side and exhaust manifold side.

I have read you can change a line of coding in the ECU and not set off any trouble codes. From the research I have done Im coming up with the European 12vs did not have EGRs, so effectively you are coding in the European version of the EGR code.

A good friend of mine has a legit version of vag com, and a good cable so I am set there.

Does anybody know what line of code I need to change, and what it needs to be changed to?!

AudiMick

European 12 valves didn't have the US Hitachi ECUs either, they were Bosch.

tylertitus14

Ok so can the Hitachi ECU coding be changed to eliminate the EGR with either vag com or a different software?

I am aware of the "un tunability" of the Hitachi ECUs, but I have seen people elude to their tune being modifiable, just not for the sake of performance due to timing limitations.

AudiMick

There was never a chip upgrade for the Hitachi, so I assume it wasn't possible or financially practical.

Why so much trouble to eliminate the EGR? You can do the "mod" which stops the EGR opening under normal driving conditions. You just block one vacuum line.The test EGR function still works and you won't get a CEL.

tylertitus14

I haven't got the chance to sit down and carefuly examine the "egr mod" but I have skimmed throught the threads pertaining to it and I don't see how in the world unhooking a line that runs from the selenoid to the pre throttle blade intake ducting could in any way shape or form stop the egr system from functioning, whether it be in test mode or during normal operation.

The hose being disconnected sees atmospheric pressure under all running conditions assuming you have a clean & adequate air filter and are naturally aspirated.

If I'm mistaken in my understanding of how the "egr mod" is accomplished could you please point me in the direction of a helpful thread or article?

If this egr mod turns out to be snake oil I was going to explore the option of mounting the egr temp sensor on the manifold and ditching the rest of the system.

I can pass emmission inspection no problem around here, I m just trying to get the most I can out of my ole 12v daily driver. I've made a "pcv" system with an inline oil seperator, all typical tune up items. Recently I welded straight tubes in the cats, and added a dynomax same side inlet/outlet muffler in the resonator location to complement the generic straight through muffler at the bumper that was on the car when I bought it (It has a nice no rice tip so I had no reason to change it. Car is very quiet. I would say stock but I've never been in one of these stock. I'm freshening up another 12v right now and swaping it and a new wiring harness/ ecu into the car, hopefuly curing my untraceable idle missfire. A little over kill, but my current engine, albeit still a workhorse, has had a rough life and has a failing waterpump among other problems. I got a good deal on a whole pullout from a local yard and it will save me downtime while I freshen it up.

Anywho just rambling now. As you can see this thing has turned into my little pet project and when I do my next wave of work I would really like to ditch this egr or do the "egr mod" if there's a functioning one out there, so if you can give me some links on the egr mod Id appreciate it.

Take care,
-Tyler
-Sent From Android 2.2.2 Root

ezveedub

From what I know, it's not really a good idea to eliminate EGR on any car. What people don't know is that EGR is used to cool the combustion chamber and it will prevent pinging in most cases. The ECU software is designed around the EGR function, so it will have timing and fueling for this function. I have seen cars ping with a clogged or restricted EGR, and run fine once it's been cleaned up and properly functioning.

JohnBoyToo

in the diesel tuning community the rage for a while was weld shut and /or remove the egr....
but after a few years they determined it actually was not a good idea there either !
an actually led to more problems than not...
and what was the real gain ? unsubstantiated hp gain claims, etc... so not worth it in a daily driver...

maybe it's the same here ?

AudiMick

There are two ways the EGR valve opens, intake plenum vacuum or manifold vacuum. The solenoid switches between the two modes.

If you disconnect the line from the plenum the valve will only open when being checked by the ECU. If the system is working and the EGR passge is clear you won't get a cel.

So the EGR valve will open only occasionally rather than most of the time.

This works, does it make much difference . No! But it's a hell of a lot easier than what you are proposing. Audiboy was the one who came up with this, and the guy knows his Audis.

ezveedub

I know Audi/VWs and advanced fuel injection systems. EGR is what most domestics fail at applying properly, but EGR is not the green headed-monster with foreign vehicles, at least with the VWAG group. It actually is designed to reduce NOX and also lower combustion temperatures that cause pinging & NOX emissions. I have seen people remove certain emission controls on European cars, only to have the car become de-tuned. Unless you have specific ECM software that coincides with removing or disabling certain functions, you're better off leaving the items intact, than removing them.

AudiMick

Agreed the benefit is mimimal , this type of enhancement is pretty much "old school". The main benefit of modifying is to delay the onset of EGR passage blockage. On higher mileage cars this becomes a re-occuring issue.