2.8 Idle issues

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cjrob

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I am having some idle problems with the car just now, when I dump the clutch the revs die to around 200-300 almost stalling the car, it then rises to about 500 then goes back to normal after a second.

this happens both when not moving and at speed.

now I had to charge the battery yesterday as I left the interior light on (doh!!!) does this having anything to do with it? just wondering as I didnt have a problem with it before.

cheers
 
Ref the battery not sure. You might have to reset the throttle body. I believe you can do this buy turning the key in the ignition barrel one turn short of starting the car and leaving it for a few minutes. It should automatically align itself(the throttle body). Failing that do a scan with a vagcom(or whatever they are called now). Failing that check all your vaccum pipework. The black plastic ones are VERY prone to perishing/cracking as they are made from a cornflakes packet......failing that remove your throttle body and clean it, repeating the alignment step previously mentioned. Failing that you could always up the idle a couple of 100rpm to see if it helps.




I too own a 2.8 and have done all these things. I have (have always had) the same problem. Much better than it was but every now and again it will stall when the clutch is dipped. And believe me, I have checked EVERYTHING.....lol.

Failed to mention one thing.....There is a possibility it may have something to do with the immobiliser/car security system.

Good luck buddy!
 
If its only just started since the battery then it will be the throttle body alignment.

As phoenix says it will align itself, just turn the ignition on and wait. You should hear the throttle body whirr and click a few times, and eventually it stops at which point you can start it and it should be fixed.
 
Tried the ingition technique but to no avail, also tried taking disconnecting the battery then reconnecting and retrying the TB reset but its still not solving the problem.

it appears when I rev it the engine almost dies, comes back up to 800 then goes down to 600 then back up again.

any more ideas?

where is the screw to up the idle speed (I should really buy a haynes manual should I!!!)
 
There is no screw, its all electronic.

When you turn the ignition on and leave the engine off, can you hear the TB do its thing?

You might need to use vagcom to force a recalibration.

Where abouts in the country are you? Perhaps someone nearby might have a lead?
 
Cjrob, is your car the 12 valve or the 30v version? You can tell by looking at the engine cover. If there is a 5v on it then its a 30v(5 valves per cylinder). If you have the 12v model then you could try cleaning the idle control valve( a detailed description of this can be found at www.audiDiy.com)....the 30v don't have an icv.

As stated, I have had the same problem with mine (30v) since I bought the car 5 months ago. Absolutely nothing I have done has fixed it 100%. Cleaning the throttle body made a small difference but hasnt cured it(though my tb was minging!!). I have tried a reset/align with s vagcom too, but the vagcom didnt pick up any faults. I have posted specifically about this before, but both on this forum and vwaudi forum no-one has managed to solve it......I read somewhere that the water pump could have something to do with it but dont see how it would affect the idle/stalling.
 
When you disconnect the battery for any length of time 2 hours+ you reset the ECU. It then takes a couple of hours of driving for the ECU to relearn everything and adjust back to its previous settings. Just give it a couple of days and everything will be back to normal.
 
I've never had the car stall after a battery disconnect. Its only relearning some fuel trims, and the base map should be able to run the engine perfectly acceptably!

Good point on the ICV. I didnt realise the 12v motors had a seperate valve.
 
its a 30v engine.

only actually been for small runs so far so I will try the 2 hour run in.

never had this problem before, used to run a 2.5 V6 mondeo and I normally had to reset the ECU by taking out the fuse and leaving it a few mins to make it run better, seems Audis are the other way round, lol

when I took the battery out I noticed a large build up of water underneath so I will have to take it out again to flush it (I am assuming there is a drain hole that is bunged up with crap)
 
Yes mate there are a couple of drain holes near the battery tray under the scuttle cover if your car has one. These become blocked over time. When I bought mine it was like an irrigation ditch! You can eithet unblock them(I used an unwound metal coathanger) or remove the rubber/plastic drain pipes obviously connected to these holes. I ended up removing them as the pipes became blocked again leaving just the two holes... I would say thats your best bet.....

If you get to the bottom of the stalling/low revs issue please let me know. I would love to stop it on mine!.....
 
"I've never had the car stall after a battery disconnect. Its only relearning some fuel trims, and the base map should be able to run the engine perfectly acceptably!"

Well that maybe true but I've had it happen to me on my 2.8Q a couple of times, revs bouncing about and stalling at every junction, after a couple of hours driving everything back to normal.
 
ran the car for a few hours now, but the problem is still there, is there anybody on the Edinburgh (or Markinch) area with a VAGCOM lead to see if the ECU just needs a proper reset
 
Can anyone help with some shots of the small vaccum hose routing that are above the throttle body the blue and black ones for a 2.4 30v as i removed all mine following fitment of a PES supercharger, and i didnt label them !
my car idles but doesnt want to rev above 1500rpm
 
I will get on it tomorrow mate/post some pics up for you, as mine is in bits at the moment!
Hows the PES? (When you get it going of course!).....
 
Thanks for the offer, I've managed to get it sorted now the moderator of SC Audi has posted some very easy to read diagrams, the supercharger vac set up differs to the standard set up. I've had it running and the first impressions are good, with my exhaust and the supercharger whine my car sounds evil, I'm dying to get it De-catted now and some further exhaust tuning will enhance what it's got now. Hoping to have it all done for GTI Int later next month which will be 3.5 years since I've been on the road. I've got another few things in the pipeline which i' shall be announcing before GTI int i'll be posting some shots of the car with some accessories i'm hoping to sell. Catch you soon.
 
FAO Craig n Ollie, did you lads sort this issue out???

Just saw the thread really, have a look at the small rubber type valve on top of the airbox, its called a carbon solenoid valve and is part of the fuelling system, it usually emits a loud clicking noise when engine is running if its suspect, it causes hunting and stuttering as yous describe if its faulty or split.
 
Hello mate! My old one was clicking loudly so I replaced it with a new one, and the issue is still present. I really have tried everything now apart from a new throttle body which is en route to me. Hopefully it will cure it as i read on here it usually sorts the matter out!
 
Hopefully then mate. Failing that, food for thought, sounds a bit mental but the coolant temp sensor on 1.8 engines tends to make the engine run crap also as its a double sensor that sends info to ecu also, read about a few folk who said the car drove better aswell as sorting the cooling issues when changing it. 1st hand experience also as i changed it on my da's passat the other week when doing the water pump, tensioner etc for him and he says it used to be trouble starting in the morning a bit aswell which now has cleared. Not sure if the cooling systems are similar from 1.8 to v6 but imagine so.
 
Foxmeister said:
FAO Craig n Ollie, did you lads sort this issue out???
Click to expand...

yes I did, by doing . . . . . well nothing really, the idle fixed itself after a few weeks, guess the ECU must of learnt a new map, just took a while.
 
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