EGR Combi Valve Failure

4.2 V8 40v biturbo - 450 bhp
4.2 V8 40v biturbo - 480 bhp (plus)
Post Reply
Dave_P
Neutral
Posts: 2
Joined: Wed Jan 04, 2023 11:56 am

EGR Combi Valve Failure

Post by Dave_P » Wed Jan 04, 2023 5:13 pm

Hi All

Doug at MRC has advised that my EGRs need replacing (car occasionally goes into an old school limp mode/throttle is unresponsive).

Slight problem, Audi have stopped making parts for the C5 and the aftermarket doesn't have any either - worldwide!

Part Numbers: 077131101 & 077131102 (72256014 & 72256015)

As its such a big job to get to them I don't want to risk using used parts, unless they can be professionally reconditioned.

Question - anybody know where I could get these parts new and/or does anybody know a specialist who can recondition used EGRs.

Any help really appreciated, I'm at a dead end with this now and I don't want to write off a car I've owned for years and love due to a couple of bloody valves!

Cheers, Dave

User avatar
Shoppinit
Cruising
Posts: 20319
Joined: Wed Dec 31, 2008 6:24 pm

Re: EGR Combi Valve Failure

Post by Shoppinit » Wed Jan 04, 2023 5:18 pm

RS6 doesn't have exhaust gas recirculation. Did you mean EGT sensors?
Daytona RS6 C5 Avant. Viper'd, Billies, Waggers, MTM box brain, C6 stoppers, xcarlink, R8 coolant cap (woohoo)
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."

User avatar
Shoppinit
Cruising
Posts: 20319
Joined: Wed Dec 31, 2008 6:24 pm

Re: EGR Combi Valve Failure

Post by Shoppinit » Wed Jan 04, 2023 5:23 pm

OK. I googled your part numbers. They are the secondary air injection valves. Your car doesn't need them. You can delete, blank off and mod the ECU to program out the SAI.
Daytona RS6 C5 Avant. Viper'd, Billies, Waggers, MTM box brain, C6 stoppers, xcarlink, R8 coolant cap (woohoo)
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."

User avatar
Shoppinit
Cruising
Posts: 20319
Joined: Wed Dec 31, 2008 6:24 pm

Re: EGR Combi Valve Failure

Post by Shoppinit » Wed Jan 04, 2023 5:25 pm

Daytona RS6 C5 Avant. Viper'd, Billies, Waggers, MTM box brain, C6 stoppers, xcarlink, R8 coolant cap (woohoo)
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."

Dave_P
Neutral
Posts: 2
Joined: Wed Jan 04, 2023 11:56 am

Re: EGR Combi Valve Failure

Post by Dave_P » Wed Jan 04, 2023 11:00 pm

Thanks for your time and help :thumbs:

I've been told by a specialist that these can't be simply removed and blanked off, they are the older mechanically operated type (no electrical connections) so they can't be mapped out of the system easily (like you can with later models). I will call and ask QS Tuning and MRC for further advice on this.

They are listed as an exhaust gas re-circulation valve, so if they are not recirculating exhaust gasses through the intake I am confused as to what else they are doing? Damn these valves!

https://www.ecstuning.com/b-genuine-vol ... 77131101b/

User avatar
Shoppinit
Cruising
Posts: 20319
Joined: Wed Dec 31, 2008 6:24 pm

Re: EGR Combi Valve Failure

Post by Shoppinit » Thu Jan 05, 2023 9:22 am

They are sometimes incorrectly listed as EGR valves. They are secondary air combiner valves.

Loads of people have mapped them out. Your "specialist" might not be as special as he thinks.
Daytona RS6 C5 Avant. Viper'd, Billies, Waggers, MTM box brain, C6 stoppers, xcarlink, R8 coolant cap (woohoo)
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."

User avatar
Shoppinit
Cruising
Posts: 20319
Joined: Wed Dec 31, 2008 6:24 pm

Re: EGR Combi Valve Failure

Post by Shoppinit » Thu Jan 05, 2023 9:29 am

Audi list them as "Kombi valves":

https://audi.7zap.com/en/rdw/audi+rs6+r ... 31-131040/

The valves are operated by vacuum and commanded by the solenoid valve which is located near the SAI pump. The flow sensors are in proximity to the pump, not the valves. They detect flow from the pump, but there is no sensor on or near the pneumo-mechanical valves. Can't remember the N-number of the valve. It'll be in the FAQ.

You can completely map out the SAI, but if you don't remove and blank off the kombi valves then you are exposed to a vac leak or exhaust leak.

I think Mɐʇʇ has posted up a map without SAI in the past. Have a look at his threads.
Daytona RS6 C5 Avant. Viper'd, Billies, Waggers, MTM box brain, C6 stoppers, xcarlink, R8 coolant cap (woohoo)
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."

User avatar
Shoppinit
Cruising
Posts: 20319
Joined: Wed Dec 31, 2008 6:24 pm

Re: EGR Combi Valve Failure

Post by Shoppinit » Thu Jan 05, 2023 9:30 am

Dave_P wrote:
Wed Jan 04, 2023 11:00 pm
if they are not recirculating exhaust gasses through the intake I am confused as to what else they are doing?
https://www.pistonheads.com/news/ph-exp ... ains/38694
Daytona RS6 C5 Avant. Viper'd, Billies, Waggers, MTM box brain, C6 stoppers, xcarlink, R8 coolant cap (woohoo)
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."

Post Reply

Return to “RS6 / RS6 plus (C5 Typ 4B) 2002-2004”

Who is online

Users browsing this forum: Shoppinit, srichards and 168 guests