1996 Audi Cabriolet 2.6E Idle Problems

[micktuggy]

Any help here would be most appreciated.
My audi had its automatic gearbox reconditioned 12 months ago and I have only done 1200 miles in the last year. It recently went in for its first scheduled check.
No problems found then went for its MOT. Passed with no problems but on the way home from the MOT happy I noticed a misfiring. I decided to service the car and replaced the plugs, oil air fuel filters, changed the oil and also changed the idle air sensor. HT leads changed as well.
The car was running really bad,misfiring and has now idled so low that it cuts out. I have taken it to an auto electrician who put it onto the diagnostic. It shows
Error 00575
Intake Manifold Pressure
04-10 Mechanical Malfunction - Intermittent
When the error is cleared the engine cuts out. When the error appears on the screen on diagnostic it will still run, albeit erratic, but the idle is so low it cuts out and I have to drive it using my left foot on the brake and rev to keep the engine running.

I have checked all the sensors are connected and clean. I have cleaned out the throttle body and cleaned the butterfly valve edges. All the hoses appear to be ok with no apparent cracks so it doesnt appear to have an air leak anywhere.
It is doing my head in and I have to take it to another Auto electrician who can spend a bit more time on it.
Has anyone else experienced this type of fault where the engine idle has become so bad it cuts out. There is no way to change the parameters of the idle as it isnt in the EMS. This is the problem with having a car where the MAnagement System was in its infancy.
Any advice?

[audiden]

My Audi 80 Avant 2.6 automatic suffered a similar problem a few months ago & it turned out to be an air leak on one of the hoses. Specific to automatics I believe, under the engine cover on the rhs - as you look at the engine - the hose on the right was split on its underside. Had it not been for the hissing noise from it I'd never had spotted it.

I'd assume these cars have an idle control valve... maybe worth checking?

The fault codes indicate intake manifold pressure so I'd be continuing to check down this road.

[Dudey Head]

Mrs Dudey's got a '99 V reg Lupo 1.4 auto & that was running like a sack of cack, spluttering & creating and the speedo started to dance up & down when it was doing it. A mechanic chum of mine scanned it & the error code was (from hazy memory) reading something to with an airflow sensor I think(sorry, can't remember exactly). Anyway, he noticed a clicking coming from under the bonnet. A plug lead was poorly & kept shorting. A new set of plug leads cured all the probs! How they upset the speedo & airflow sensor (if that's what the code was!) I've no idead, but it did!
Hope that's of some help!

[micktuggy]

Firstly thanks for the interest and comments,

I took it to the Auto Electrician and it has presented itself as said, an air leak on one of the hoses to the MAF sensor.
It has been replaced and the engine now idles a lot better. There is another problem now with the gearbox. After having the autobox re conditioned last year it is now slipping and i can smell the clutch burning so it is going back in there tomorrow.
As long as the idle is now fixed it has taken a weight off my shoulders I didnt need.
Thanks again for your help.

[audiden]

Glad to hear your idling problem has been fixed.

My autobox has been faulty since I got my car in the beginning of last year. It has a delay between changing up from 2nd to 3rd of about half a second or so & you can usually feel all the changes. When driving in town, with the gearbox oil hot, the box goes through its changes perfectly. Dunno what the problem is... These boxes seem prone to failure... not unlike the 2001 - 2003 approx - A4's with their problematic transmissions!


I have a replacement box to fit that'll need a filter change I guess & a general check over beforehand.

How much did the original box rebuild cost if you don't mind me asking?

[micktuggy]

Hello Audiden,
I had the box repaired because it was slipping through gear change. It cost £1400 plus pennies.
I thought it would be the end of any problems...not so.
I also thought this recent repair was the end of my problems...Wrong again.
The idle is now up and down from near 0 revs to 1000 and sounds terrible.
I cant get the car back to the garage I took it to because it stalls and I dont want to get stuck between places.
I had a pin ***** leak on the expansion tank so decided to change that to solve on problem.The engine was getting very hot. Once changed I was going to change the alternator belt, water pump and thermostat to make sure the water was flowing properly. NIGHTMARE. I snapped the bolt off the tensioner.Managed to get the new belt on after deciding to stop and take stock.
I will be putting it into a garage and save my fingers and thumbs. Getting too old for this. My experience is limited and I dont want to wreck what can be a great car again so the experts are going to get it and I will pay near enough what they want now.
Take my advice...leave it to an expert or trained mechanic. Tinkering is one thing, pulling off pieces of the engine is another
Everything is back as it was before I thought I was a mechanic so now I will bit the bullet.
Thanks again for all your comments but I give up!

[scotty33]

Mick,

Is the fault code is still pointing toward intake manifold pressure? If so this could be down to a split hose.
As far as I know, the 2.6 does not have a maf sensor at all, this is why the map sensor is so important on these cars. The map sensor is mounted inside the ECU and has a small bore pipe or hose running friom the ecu to somewhere on the intake. I read somewhere that where the pipe connects to the sensor (inside the ecu) the pipe changes to a different type of rubber which can perish. It is probably best to check the external pipe thoroughly first, but bear this in mind.
The ECU is located on the firewall in front of the passenger's feet. (behind the glovebox and blower ducting)
I don't know much about autoboxes, but is the fluid level correct? There is not a clutch in the normal sense with auto's maybe you are smelling oil/fluid leaking onto the exhaust?
Have browse through http://www.12v.org/
A good v6 resource but biased to the 2.8 as the US did not get the 2.6

[micktuggy]

Thanks Scotty for the 12V Page. It does give some great info and it has made me think again about taking on the water pump change. It got me so angry the other day through shear frustration I thought I was going to damage the car beyond reasonable repair so I took the count to 10 approach and decided to quit.
The manifold pressure was down to a leak in the pipe as you said but thiis was sorted out last week.I has since got this undulating idle which I cant fathom. I might change the throttle potentiometer or see if it need testing as I removed the sensor and the idle steadied up. ROom for some more investigation.
I will post what I find out
Mick

[scotty33]

Hi,

It's good you feel more confident, but the TPS probably now needs to be reset. This can be done with Vag com or similar but it should be worth trying this reset procedure as posted by Vampire:

http://www.vwaudiforum.co.uk/forum/showthread.php?t=34879&highlight=*throttle*

[audiden]

You seem to be very patient with your Cabriolet...

My last Coupe had seemingly continual problems so when the water pump started making noises - the cambelt had been done not long before I got the car & the pump had been changed then - I had simply had enough and sold the car at a great loss. The car is still on the road 2 years later so it couldn't have been that bad in retrospect.

I'm needing to replace one of the intake manifold hoses on my 80 as its split & I'll certainly be resetting everything using the suggested method. I disconnected the battery, waited for a few minutes & reconnected it last time I had problems & it seemed to do the trick though.

I wonder if your problems could be blocked up crankcase breathers... asumming the V6 has such a system?? My last car, a Vauxhall Cavalier (way more reliable than any Audi I've had!), had a blocked breather system & gave similar problems to what you're experiencing.

I fear the time when I get round to looking at my autobox problem... but I've had enough of driving the car the way it is... then there is the whine from the PAS rack... :aargh4:

[micktuggy]

Hello there,
Thanks for all the replies. I ended up having to put it into a garage to get the water pump etc changed.
I needed to get a cam belt and was told when it was removed I would have to get the Cam kit. I agreed this as i had accepted my fate and trust the guy who was doing the job.
After he had replaced all the parts he said it was out of timing and was overheating due to the water pump seizing. I was lucky that the cam belt didnt snap with the obvious consequences. The thermostat was seized also so due to the increasing temperature it was throwing the sensors out and affecting the mixture. As it was running too rich it had the knock on affect I was experiencing. I am picking the car up this afternoon and fingers crossed that will be the end to the problems.
The breather pipes for the crank case were slightly clogged with oil residue but not of major concern. I throroughly cleaned all the air intake and breather pipework as a matter of caution during the yearly service I give it. As it was only doing low mileage I had neglected the engine slightly for about 18 months and I think the main problem is the lack of use.
I will be more careful in future and give it a bit more TLC. They are a great car both in looks and drive so I think I will keep it for a few more years. It has been a great car for 8 years until this past year where it has cost me the best part of 2 grand. With that in mnd it should be worth holding onto for a bit longer and get some more enjoyment out of it.
Pity the weather is crap cos it feels good with the roof off bombing along the motorway.
Hope this has been a bit of help for anyone suffering similar problems. If you are a half decent mechanic then attempt the repair yourself as it is quite a good engine to work on. If you are only a half decent tinkerer then forget it. You need specific tools for the Cam replacement alone so its just not worth trying and messing up.
Cheers, Mick