My boss has an Audi A8 2.8 fitted with an ACK (V6) engine.

He changed the battery on it, and ever since it stalls and idles very slowly.

Anyone know about these engines, and this issue?

It's an auto box by the way.

 

Not familiar with the europe spec models, shoot techbod a PM (private message), he is a UK member and can handle your questions.

 

auditech79, thanks for the reply, I'll send techbod a PM.

I've been doing some reading, and so far the ISV looks like the best starting point. I'm quite familier with these causing problemsfrom a few years ago when I had a Mk2 Golf GTI.

 

since you changed the battery? that's listed as one of the problems for incorrect idle speed ( check electrical connections engine and battery ),
other faults are IAC/and ISC
TP sensor,
MAF,
ECT,

 

Hi newbee here,
Thats the same engine as mine. Does the engine cut out at traffic lights when you come off the throttle? The ACK engine doesn't have a separate ISV; I ended up replacing the entire throttle body for £150 from vagparts. Or at least give it a good clean once removed from around the back of the engine.

 

techbod, Ska,thanks for the response, since my last postwe havedisconnected and re-conntected the battery, Cleaned the throttle body with carb cleaner whilst still attached to the inlet manifold, and repaired/cleaned out broken breather pipes.

After doing this, we carried out the throttle body adaption using vag com. (By the way no fault codes are present).

The car now idles at 800rpm in park, which drops once in drive, but slowly increases back to 800 rpm.

The engine is very slow to react to an increase load in a zero throttle situation, i.e. slowing down coming to a junction the revs drop to around 400 rpm, and then when steering the additional load of the power steering is enough to drop the revs a bit more causing the engine to stall.

Ska, you are correct there is no ISV, so the idle is purely controled by the throttle body. Did the new throttle body completely cure the stalling and low idle problem?

 

Hi Corradophil,
Yes it did cure it ;chances are that your cleaning has improved things but you realy need to remove the TB because of its location its impossible to clean the other side of the butterfly, bit of a tight squeez back there, good luck

 

Ska, your right, it is very tight, although with the exception of removing the throttle body from the inlet manifold it was all in pieces anyway. Out of interest is your throttle body a single large butterfly, or two butterflys. Looking at various diagrams etc the ACK is shown as having two butterflys, but this on definately has only one, which shown as being fitted to the ALG engine.