2.8 Quattro misfire

[tomti]

hi chaps, today i bought a 1997 quattro 2.8 v6 with a couple problems and hope you can help.

It has a misfire, not all the time, but most of the time. Well it feels like its always on idle and low revs, but if you rev it, sometimes its fine over 2-3000 revs and other times (most of the) its all the way through the rev range.
The fella i bought it off reckons he recently replaced the plugs and also the mass air meter, which does look new so i kinda believe him on that but its still there. Im thinking maybe its a coilpack mucking around???

Im new to audi's so was wondering if anyone could offer some advice or tell me if theres a common problem on the 2.8s that i could check?

Cheers, Tom

 

[tdia4]

Check the plugs have been gapped properly first, then see how it runs with the MAF disconnected. Could well be the coilpack though.

I would get it checked for error codes aswell and see if its got anything logged about the problem.

 

[aragorn]

dont the V6's have ignition leads too?

 

[tomti]

Cheers for the replies guys, I've just booked it into my mates garage for Monday so he can stick it on the diagnostic machine. I'll let you know what happens

 

[tomti]

also, tried unplugging the maf whilst the car was idling and the engine dies straight away. Is is supposed to do that?

 

[A4Q]

I had a similar problem but not so severe, appeared after the CO / fuelling was reset (lowered) for the MOT. Was only on pick up from low revs, I switched to Super Unleaded and it`s all but disappeared.

tomti - any news ?

 

[tomti]

just been down to see how my mates getting on. He was waiting on another set of leads. 3 of the originals were f*cked so im hoping thats where the problem lies.
You gotta love buying cars off evilbay lol. The seller claimed its had new plugs and leads. Well, the plugs are new at least but not the leads. Also it had a blow from the exhaust, and the fella reckons its had new cats but is blowing from where they join the centre pipe.
I always take what sellers say with a pinch of salt. Another load of cr4p. My mechanic has had to weld the exhaust just after the cat and it was the flexi pipe on the drivers side that was blowing badly so he has done a repair on that. Exhaust all sorted although he did say the emissions were sky high so he thinks one of the cats is knackered. Not sure what to do about the emissions as i dont want to be buying new cat convertors...

 

[tomti]

right update time. Found the problem. He plugged it into the diagnostic thing and it came up that the Throttle Opening Valve was malfunctioning. Does anyone know how much roughly this could cost to repair/replace?
Im guessing its a big job as i believe its at the back of the engine near the bottom of the 'v'?

I want to work out whether its worth spending the money on the car or just get rid???

 

[murran]

hmmmm. what was the exact fault code it came up with?

not a big job to remove it, 20 mins if that!

clean it and check the adaptions reset ok. if they dont its knackard. if they do 99% of the time its fine.
they are usually very reliable. unlike modern vag crap.

a second hand one is a real possibility concidering a new one is probably 3-400 quid.

 

[tomti]

cant remember the exact code i left the printout at the garage. 20 minutes? that quick?

 

[tomti]

anyone?

 

[murran]

really quite easy tbh. becareful of the breather pipes that clip on the inlet trunking, they go really brittle with age and the oil fumes.

 

[phoenixv6quattro]

Whats the throttle opening valve? Throttle body/part of?