CAT and Engine block damage - advice please

[GaryCollinson]

Hi all, my expensive RS6 experience continues...

Last time I made an appearance on these forums I had fuel starvation problems causing hesitation issues. one fuel pump, one regulator, a complete timing belt kit, replacement spark plugs and an aux belt later my misery was finally over. (ok, I didnt have to do the belts but I had no evidence they had been done previously)

Last week I let the missus take the car to work and 30 mins into her journey she rang me to tell me the call was losing all power and would intermittently fail to accelerate. I told her to get to work and I would pop down and take a look, ten minutes later she informed me the car had smoke belching out of the bonnet. PANIC!!

Anyway, the garage have contacted me and said that the CAT is damaged and two of the engine mounts have melted, which is all well and good but that is not exactly establish the cause of the problem. Does anybody have some pointers that I can direct towards the garage as the seem intent on fixing the damage but not establishing the cause! I am reluctant to take it direct to Audi as they are very expensive in the Middle East.

[posterboyj]

Difficult one, I guess you'll need to bend over and take it. There is no reason not to give you an itinerary of work + bill of materials + labour cost

[Daveperc]

Assuming it is still running then first get Vagcom on there.

If it isn't still running it sounds to me like a blown turbo, probably as a result of failed oil seals somewhere - hence oil into exhaust and onto cats - lot's of smoke. Not sure about the burn engine mounts, unless it blew oil all round the bay and that caught fire.

Afraid it sounds expensive!

Dave

[GaryCollinson]

As far as im aware the have some diagnostics kit but possibly not Vagcom. They are currently looking at the relay that controls the fuel pressure but I think that is unlikely as there has been unburnt fuel in the CAT, whereas if it was the relay id assume there would be no fuel getting through.

I dont think its turbo related (hopefully) as after the smoke incident and a check over, the car drove perfectly for 10K to the garage.

I hate intermittent problems

Gary

[bam_bam]

I'm gunna say it was your wife leaving the handbrake on. Why was she not in the kitchen making you a sandwich?
So, the guys doing this work on your car, are they any good? It doesn't sound right, engine mounts melting?
Where are you based? Can you get your car to Camberley Audi or MRC or Unit20 or AMD?
I think a second opinion would be invaluable right now.

[Daveperc]

Bam Bam - it's a mighty long way to Camberley from the Middle East (see end of first post!)

Still, it would be a fun run, and would defo show up an intermittent problem!

I'm intrigued that the "Engine Mounts have melted" - I suspect this could be the cause of the problem - though no idea why. There are sensors in the mounts which will cut the power if the mount is damaged, and they have been known to fail, though not as far as I know, in flames/melting. And how do they know the Cats are damaged - it's a strange place to visually inspect as a first look??

Dave

[GaryCollinson]

When the car is running I would happily do a run from the Middle East to the UK... Doesnt really stretch its legs as much as I would like.

As I understand it because of the intense heat in the CAT this caused the engine blocks to melt.

I wasnt aware that the blocks were able to cut the power which could possible explain the lack of power, however, there seems to be a chicken and egg situation going on. Is it possible the engine blocks have been damaged causing the lack off power but continually driving the car has caused the CAT to get extremely hot further damaging the blocks (hence the smoke)??

As you are probably aware, mechanics is not my strong point...

[GaryCollinson]

Sorry Bam, forgot to mention the wife was picking up my dry cleaning ha ha.

Yes these guys have a very good reputation and a lot of expensive cars in the workshops (that isnt to say they are being fixed!)

[bam_bam]

Bam Bam - it's a mighty long way to Camberley from the Middle East (see end of first post!)

Error. I think I've just taken the award for not reading before posting... Macdaddy held that award previously.

[Shoppinit]

I'm intrigued that the "Engine Mounts have melted" - I suspect this could be the cause of the problem - though no idea why. There are sensors in the mounts which will cut the power if the mount is damaged

The ECU doesn't reduce power in the event of an engine mount failure.

Things smoking under the bonnet don't sound good. The cats could overheat if the mixture is too rich and possibly super heat something under the bonnets. Seems like a bit of a stretch, but vaguely plausible.

If it's intermittent and there is lots of smoke then I'm going for something causing the mixture to run super rich.

[Shoppinit]

Last time I made an appearance on these forums I had fuel starvation problems causing hesitation issues

Incidentally you never posted back to say what the problem was. It would be nice if you could do those that tried to help you out the courtesy of telling them what the correct diagnostic was.

[GaryCollinson]

It would be nice if you could do those that tried to help you out the courtesy of telling them what the correct diagnostic was.

If I was confident to identify whether a) the problem has actually been fixed or b) the garage havent replaced a number of parts without actually knowing what the fault was, I would be happy to contribute. Unfortunately due to the skill level out here (including the Audi main dealer) I am reluctant to say what actually fixed the issue.

Both MAF sensors have been replaced along with the fuel pump and regulator. Again, because im still having power cut outs I cant say that the issue is resolved.

[GaryCollinson]

** UPDATE **

OK, I eventually gave in and took the car to Audi as I needed an experts opinion... They have suggested that the Vacuum system and Exhaust gas sender/sensor is replaced. Again, my lack of mechanical knowledge prevents me from knowing whether this will resolve the problems.

They did also mention that I had a P0741 code also which they have suggested I replace the gearbox! they want approximately £4000 to do that...

[marv8]

** UPDATE **

OK, I eventually gave in and took the car to Audi as I needed an experts opinion... They have suggested that the Vacuum system and Exhaust gas sender/sensor is replaced. Again, my lack of mechanical knowledge prevents me from knowing whether this will resolve the problems.

They did also mention that I had a P0741 code also which they have suggested I replace the gearbox! they want approximately £4000 to do that...

I am not an expert (calling Shop) but the p0741 can be caused by low ATF or a sticking solenoid in the valve body I believe - did they check the level? It's 17125 that's the killer, pretty much always gaurantees the gearbox has eaten the TC.

Incidentally if it's Audi £4k for a new gearbox and labours is very very cheap - normally £3k in labour alone here in uk!

[GaryCollinson]

Thanks Marv, I really do worry over how they actually come to these conclusions... low fluid or a replacement solenoid doesnt really justify a new gearbox. Who knows what testing they have done.

Shop:- does the exhaust gas sender control how rich the fuel is? (as in your previous diagnosis) Could this be what has caused the CAT damage?

Thanks again for all the help