Step right up place your bets

Ok had the old girl out for some errands today before hopefully some rain/snow comes and helps put out these fires. Left a clients house and car was idling very rough and surging to 1200 back down repeatedly. Fortunately was close to the shop who I have work on the car. Took off the air box and it sounds like a shop vac sucking air from under the intake manifold. So going in for a better look in a week. do a smoke test and look for the leak. Any guesses as to what could be under that manifold big enough to make that loud of a sucking sound. It's definitely not some little 1/4 inch vacuum hose. Could the manifold be cracked or is there something bigger running under there we couldn't see? Whats your guess all you veteran wrenchers?

P.S. he did pull codes and there were a few. But nothing throttle body/intake related, couple of intermittent misfires and the O2 sensors doing a sporadic code trip.

DKP

Suction Jet Pump going out? Audi was kind enough to mount this right under the intake manifold and the end decides to pop off...a whole paragraph of revised part numbers when you look it up. If you shoot some carb cleaner under the intake when the car is running and it changes the idle characteristics...then at least count on a vac leak of some sort such as the suction jet pump or another check valve under there...most likely an intake removal project if this test is positive (idle changes when spraying). This repair can be made with the engine still in the car, but it is definitely a biatch...Audi also decided to put a guide pin in the hard intake pipes that the MAF's attach to which makes for some interesting leveraging on the intake manifold to remove and re-install (2 person job at times). If you need to get into this, plan on doing the o-rings on your injectors too since you need to pull the fuel rail out to get to the intake manifold bolts iirc.

Also double check your o-rings around the MAF's, but that would be a "wish it were that easy" kind of fix, but a prudent first check item.

http://www.fototime.com/F5394A8D1422202/medium800.jpg

http://www.fototime.com/20A43F6C2C68585/medium800.jpg

http://www.fototime.com/104B01325EAE70E/medium800.jpg


What you are seeing with these pics...top photo is the suction jet pump itself...see how the end pops off.
Second photo is the bottom of the intake, belly up on the bench, you can see "most" of the valve still attached.
Third photo is obviously the area under the intake and you can see the little orange cap that is supposed to be one piece with the valve.

Muggy thanks so much for the answer. The tech did just what you said with the carb fluid and the idle dropped almost to a stall then recovered and settled back into a lumpy idle. This work is above my pay grade although I am still feeling pretty smug that I changed my own front axles last weekend. (What a dirty job after the grease has flown everywhere) Is there anything else I should do while he has that manifold off? Thanks again for the reply.

No problem....I would bet a solid 90+% diagnosis then if your tech did my test and the idle stumbled. It's more of a pain in the rear job that takes time....those bastard combi valves need to come off which are always fun (mine are gone now, woohoo!).

Does your mechanic feel confident with doing this? Everyone needs to be a first timer at some point, but I'd be careful as the first time will definitely be more time on the job (aka labor cost!). Mine took about 12 hours over a couple of days taking my time...next time around, probably 8 hours or so since I know it better now.

Not much as far as parts cost on this, mainly labor. You'll need the valve (about $60 OEM), intake manifold gaskets, injector o-rings and little plastic retainer rings (suggested), combi valve gaskets (suggested), and then coolant, etc. depending on if you need to pull a hose to get to service position. Really the only reason to go to service position (if I remember correctly), is to get the frick'n bolts out of the front of the intake pipe into the throttle body since there is zero room otherwise. Fortunately the valve covers can stay on which saves some time and hassle.

Not sure where you are located, but I'd be happy to help if you were anywhere near me in MD. Hope this helps! Feel free to PM for email or phone if you'd like to talk about it...~ Eric :cheers:

Yes I'm very confident with my the guys here in Colorado. All they work on is Audi, Porsche, Mercedes etc. We have three RS6'S in the Vail Valley and I think he's worked on all of them. I went to them the first time based solely on what was in the lot. From 356's to newish 911 turbos, Maserati's, Audi etc. Restored an old 90's Audi S wagon for a guy that turned out beautiful so all good in that department. Hopefully I'll have time and I can help. Be the parts cleaner guy etc and get some more knowledge. Between the RS6 and my 04 Allroad It's been an expensive summer already. Was just about to put the RS to bed for the winter and now this. Right now this car reminds me of the hot crazy girl from my college days. When everthings working its awesome the rest of the time you trying to get away from her. I'm not afraid to spend money on the beasts I just wish there could be more good times between visits to the Audi Doctor.

Hey I forgot to ask hows the new lift? Do you like it?

I always highly recommend relocating the SJP. The last time this subject was brought up I did a little write-up. Muggy did a good job of describing the replacement process. Relocating only serves the purpose of minimizing the scope if it happens to go bad again. It's a $20 (aftermarket) piece of plastic buried underneath the intake that will cost you hundreds in labor/parts to replace in the factory location. Since you're not doing the work yourself this might not be an option considering many shops are reluctant to do anything custom. Anyway, I also included a "while you're in there" list in that post that might be useful. Cheers.

https://www.rs6.com/showthread.php/3...l=1#post291735

Sounds like you are in good hands with the shop! Honestly, if you are ready to put it to sleep for the winter, it won't hurt at all to leave it in hibernation mode and deal with in the spring. Although, I love to get mine out on a nice crisp winter day when it's nice and dry out, so it's a bummer when you can't get in and run it around the block for sure.

As far as the lift, I should have bought it years ago...it gives me so many service options to safely work on the car in a smaller garage space!

Yes I'm with you on the winter runs when dry. Learned not to leave cars to long the hard way. Have an 88 Carrera that gets the same winter hibernation program. Had a busy winter and didn't move it all winter. By the time April came all dried up with old leaking everywhere. Pull the engine reseal just about everything. Now all hibernating cars get the monthly exercise program. Plus my anal retentive nature won't let me sleep if it doesn't get fixed.

BTW thanks everyone for the input. I'm not a big fan of the whole Facebook, Twittersphear, blogging stuff but I can truly say this is a great forum and not to sound to corny but it is truly an RS6 community. Full of information and possibly more importantly moral support just short of a physiatrists couch.

I'll update when I have the official diagnosis.

Thanks again all

DKP

Definitely keep us posted...always good to track these things.

:incar:

And the winner is Suction jet pump. Finally got the manifold off at the shop. So of course I got into the while we are in there lets do this and this oh and we may as well do that. So ordered every damn Coolant line, crank case vent hose, intercooler hoses and vacuum hose from DO88 and will replace everything we can reach with the engine in. Also have one tired intercooler so having both redone by Apikol down in Denver and reinstall those with new hoses. Also wanted to replace the auxiliary coolant pump under the manifold but no longer available. Troy at Apikol said use one from a 2.7 and use the Old RS6 bracket. Anyone out there have any experience with that swap.

The old girl is giving my wallet a bit of a beating. Hopefully I'll be good to go now for a bit. I don't mind keeping her up I just need more time to enjoy the car between financial beatings. Just makes you lose that loving feeling. Thanks everybody for the input. Invaluable as usual. Linked my techs with Muggys refresh and this thread. Very impressed with the knowledge on the site. When you only see an RS6 every couple years I'm guessing its hard to remember all the little
pieces parts of which there are so so many.

Thanks again everybody. And Muggy your refresh is looking good. Consider me very very impressed.

Quote:

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Originally Posted by DKP

Troy at Apikol said use one from a 2.7 and use the Old RS6 bracket. Anyone out there have any experience with that swap.

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I mentioned this in the link I posted above. I'm running a knock off 2.7 unit I found on Ebay for <$50 instead of the pricier Pierburg unit. YMMV.

Quote:

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Originally Posted by bethridg

Replace the after-run pump. 078121601B is for an A6/S4/Passat (re-use the rubber insulator/isolator from the RS6) otherwise you'll probably only find 077121599A which is the pump and RS6 specific bracket $$$.

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Glad that I could be of help....and glad that you found your culprit! I decided to start my thread to be informational and include info that I could only find in bits and pieces elsewhere to help others in the future (and maybe remind myself what I've done too!).

Those Do88 hoses do look nice and hard to resist. It's a shame that everything comes in increments of hundreds of dollars for parts on these cars...but damn, it is sooo fun to drive!

Yea I didn't feel like spending that much on parts myself but I thought hey everything under the hood has been cooking for 17 years now so may as well replace everything we can reach and save the rest in my RS6 parts bin. Hopefully they perform as advertised and maybe more importantly molded correctly. Always a bummer when non OEM parts are just a tad off or worse way off.

Bethridg thanks for the after run pump tip. Unfortunately already have the 2.7 version in hand so will use and report back on success or otherwise.

Quote:

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Originally Posted by DKP

Bethridg thanks for the after run pump tip. Unfortunately already have the 2.7 version in hand so will use and report back on success or otherwise.

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078121601B is the 2.7 aux coolant pump...