A8 Stalling At Junctions

[Billbags]

Hi all at Tyresmoke,

Can anyone point me in the right direction?

My battery went flat the other day. I had the car 'jumped' from one of those jump start units. Anyway, since then , but perhaps coincidence, the 8 stalls at junctions. Revs on start up are fine (around 900) she drives great but as I approach a junction she drops down the gears and the revs teeter at around 400. At this point, I can either catch the revs with my foot on both pedals (dangerous), or watch as she stalls (pain in the neck).

I am thinking about cleaning the ICV or the TB. I just hope and prey that it has nothing to do with the ECU.

Any ideas out there?

Best wishes to all,

Mark

[cruiser647]

Hi all at Tyresmoke,

Can anyone point me in the right direction?

My battery went flat the other day. I had the car 'jumped' from one of those jump start units. Anyway, since then , but perhaps coincidence, the 8 stalls at junctions. Revs on start up are fine (around 900) she drives great but as I approach a junction she drops down the gears and the revs teeter at around 400. At this point, I can either catch the revs with my foot on both pedals (dangerous), or watch as she stalls (pain in the neck).

I am thinking about cleaning the ICV or the TB. I just hope and prey that it has nothing to do with the ECU.

Any ideas out there?

Best wishes to all,

Mark

I think it might be a combination of a stretched throttle cable, dirty TB and dirty ICV. All are easy to get to.

I think either alcohol from Lloyds Chemists and/or Carb cleaner from Halfrauds (£4 for a spray tin) + plenty of elbow grease!

[PsYcHe]

Checking the play in the throttle cable is easy enough (On V8s at least). You can see the cable and adjuster to the rear left of the plastic covers, see how far you pull it before the revs pick up and then adjust the little clip (dont drop it FFS!!) to just before that point and see how it goes.

I would think that if the jump fried something it would be worse than just stalling at junctions.

If all else fails, spend a few hours in a car park practicing left-foot braking

[Ska]

Try the throttle adaption sequence( IGN on press acc.pedal down to ground hold for 10 sec then release, switch of IGN). But I reckon its the TB/ISV that needs a clean at the very least or replacing. I had this happen to me and needed a new TB as mine doesn't have a separate ISV.

[Billbags]

Hey Guys!

Thanks, Cruiser647, PsYcHe and Ska. Yeah, everywhere I look, it seems that the problem could be with the ICV or the TB. So, unless Ska has given me the miracle cure (I really hope so) I know what I'll be doing this weekend. I just hope that I don't screw this up. If any of you have a page or two of instructions for removing the ICV and the TB, please drop them to me at:

[email protected]

Nevertheless, thanks for being samaritans. I heard that Tyresmoke was the best forum. And, that is self evident.

Thanks again,

Mark

[Billbags]

Hi Ska,

The 8 is stalling at 80% of junctions now. So bad! No luck with the Throttle Adaption Sequence. I bought some red fuel additive from Tescos today that 'promised' to clean out the fuel system of built up carbon. No luck there either. So, it seems that I will have to check the throttle cable, as PsYcHe suggested and then give some serious thought to stripping out the TB/ISV. But, I am thinking that this isn't a job for a novice! But, when needs must . . . .

Thanks guys,

Mark

[msey]

HI there,

I am pretty sure that there are oil breather hoses around that area as well that tap into the Air intake. These can become perished and you get holes in the rubber hoses. These let in air past the Air Mass Filter and can knock out the running as well. I would check these as well. You will soon find out if you touch them, they will be very soft.

[Ska]

Hi Ska,

The 8 is stalling at 80% of junctions now. So bad! No luck with the Throttle Adaption Sequence. I bought some red fuel additive from Tescos today that 'promised' to clean out the fuel system of built up carbon. No luck there either. So, it seems that I will have to check the throttle cable, as PsYcHe suggested and then give some serious thought to stripping out the TB/ISV. But, I am thinking that this isn't a job for a novice! But, when needs must . . . .

Thanks guys,

Mark

whats the engine/size and gearbox code (on sticker in spare wheel well)? also year?

the additive isn't going to clean a dirty TB or ISV, you'll have to remove the TB and clean as per above, let me know of the details above for your car and I'll dig out the procedure to remove it+++

[Billbags]

Hi Ska,

The additive? I know, I was just clutching at straws really, hoping for a slight improvement. Anyway, thanks for taking the time out to help. The instructions (A8 For Dummies - Like myself) would be a big help.

The following are the details from the sticker in my service History;

Engine output/ 2.8 142KW

Gearbox / EG2 A5

Month and Year / 02/98

Engine Code/ ACK

gearbox Code / DRD

Thanks again Ska, this will really be a major assist for me.

Mark - [email protected]

[nikw]

Don't bother mucking about with alcohol and the throttle body!

Instead take the plastic shroud off the top of the engine (four cross-head screws) and inspect the breather hoses running between the two cylinder heads. I'm willing to bet that you'll find them perished. If so this is what is causing your stalling problem.

You can get replacement hose at any decent car parts store (e.g. Halfrauds) although it's likely to be sold as coolant hose. Measure it up against the old one and cut to length. Here's a pic of the hose I had to change on my car:

[Ska]

Hi Mark,

Your engine is the same as mine (though a different Gbox). NickW is right in saying check the breather hose (low cost solutions 1st), but the one pictured in his reply is for the V8's which to the best of my knowledge is a simple rubber type. The Cam cover breather hose on ACK's (V6's) are covered in a corrugated plastic shroud and is proly a dealer part only (see picture) and seems to be a lot tougher than those on the V8’s, but its still worth inspecting all breather hoses especially ones that go to the TB and air ducts. Having said this Cruiser647 also has an ACK engine on his A6 and recently changed his TB due to similar probs and I think he's all sorted now; plus as I said I too had the same problem and the engine would stall at all lights and even got to the point that it stalled as I was slowing so no power steering:eek: (do a search for stalling under my name). So there is a pattern there. Also unlike the V8's the ACK does not have a separate ISV; this function is integrated into the design of the TB.

Weather permitting I am gonna do a biggish service which includes cleaning the TB (its about due now I reckon), amongst other things like the MAF, plugs and usual serviceable items.

If you do decide to have a look at the TB its located at the back of the engine (knuckle scraping involved back there as its really tight for space), and secured by 3 or 4 alan bolt.

But first you’ll have to remove the air ducting the plate as shown in the picture with all the hoses (2x 10mm bolts). Disconnect the Cruise control actuator from the TB held in place by 2x10mm bolts then attempt to remove the 4 alan bolts of the TB ( a mirror comes in handy here). Be very careful don’t drop anything or your be there for ages trying to find it!

As you can see from my old pics (sorry about quality – phone camera) the TB gets quite dirty and the inside of the black air ducting leading into the TB also gets a fair share of oil and crap so that’ll need to cleaned as well, Ultimately a check of any Fault codes will be more helpful with VAGcom. Let us know how you get on. Oh, also the TB from Vagparts.com was £148, good luck

Khuram

[PsYcHe]

Guys... On a slightly related note. My 8 has been smelling a bit of Oil after a journey when stationary. Looked under the cover at the hoses and while I can't see an obvious leak, there's a lot of oil buildup next to the filler cap and the hose itself feels squishy and slightly sticky.

That a sure sign of it being fekked?

[Billbags]

Hi everybody,

Sunday afternoon and time to attempt a fix with my very reliable neighbour who was once a motor mechanic (still is in my eyes). Five hours later! Just finished.

After the work done, I took the car for a good run, hammering it into junctions, etc., hitting the brakes to a halt and the 8 hasn't stalled. The idle revs at start up are around 800 but tend to go down to 500 at junctions - but doesn't stall! Should the revs be higher? :confused:

Work done:

Breather hoses (not the rubber type from V8's but the moulded plastic type); they were all very brittle and the one that NIKW mentioned, unfortunately broke when I accidentally leaned on it. I did a temp fix with those. Halfrauds didn't have anything suitable. So, a journey to Homebase for a washing machine hose.

The TB: I couldn't get this completely off but cleaned it out as much as possible through the opening past the butterfly plus both sides of the butterfly itself. The problem that I found was that it was so close to the firewall for my limited toolbox. We managed to get the plastic elbow off but that was far as we could get. Nevertheless, the crap that was in the TB felt extremely gritty and must surely have been causing the problem.

My thanks to Ska, Cruiser647, PsYcHe, msey and nikw (not to mention my talented neighbour) for coming to my rescue.

Job done (fingers crossed). Just need to get the 8 in for a good service now.

Thanks everyone,

Mark

[timberline]

Hi Psyche

My A8 4.2 Q used to smell of oil after a run and when stationary, This was the final drive oil seal and the oil was dripping onto the cat. So an oil leak wasnt immediately obvious.

Just a thought.

[Ska]

Or cam cover(rocker cover gasket), perhaps?

Welcome to TSN Timberline+++

[nikw]

NickW is right in saying check the breather hose (low cost solutions 1st), but the one pictured in his reply is for the V8's

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*D'oh! Serves me right for posting without checking which car I'm talking about!

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P.S. Not enjoying the post editing - carriage returns don't show up until I post my reply and it keeps adding spurious asterisks (using advanced edit mode, Opera 9.5 beta)*:mad:

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Bah! I give up!*