This damn Idle :(

Pubemammal

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Hello guys, I am struggling with this awful idle issue on my 1998 A3 1.8T.. I have tried unplugging the MAF, cleaning the TB, resetting the TB, replacing vacuum hose, checking all other hoses for leaks/splits etc. Still the problem persists.

The car will hunt for a few seconds then settle down, however if I coast along with the clutch pressed down, the hunting will continue until I come to a standstill!?

[YT]]Idle - YouTube[/YT]




Any help or ideas would be appreciated.
 
Ive got similar issue. Starts lumpy to.if you rev it its rough. Is yours? I was advised to get my injectors cleaned.
 
A new ignition control module fixed my erratic AGU issue, I went through new plugs, new coils, fuel filter and vacuum lines before I took a punt changing the ICM.

You can test it with a volt meter there's guides online but I just decided to change mine.
Idle was that bad I was convinced the flywheel was shot and about to exit the gear box.

Good luck tracking down the issue
 
Ive got similar issue. Starts lumpy to.if you rev it its rough. Is yours? I was advised to get my injectors cleaned.

Mine is fine through the rev range its only the ideal causing an issue buddy :(


A new ignition control module fixed my erratic AGU issue, I went through new plugs, new coils, fuel filter and vacuum lines before I took a punt changing the ICM.

You can test it with a volt meter there's guides online but I just decided to change mine.
Idle was that bad I was convinced the flywheel was shot and about to exit the gear box.

Good luck tracking down the issue

Ah ha I think you might be on to something here matey... as the issue started around the same time I fitted the s2k filter and had to relocate the ignition control module. Would the relocation of caused that to happen? It is currently fixed to the forward facing side of the bulkhead.
 
Mine is fine through the rev range its only the ideal causing an issue buddy :(Ah ha I think you might be on to something here matey... as the issue started around the same time I fitted the s2k filter and had to relocate the ignition control module. Would the relocation of caused that to happen? It is currently fixed to the forward facing side of the bulkhead.
location should matter too much if it is secure.Theres no clear cut symptoms when the ICM goes, anything from intermittent spark issues to non firing of specific cylinders. Most annoying is that it doesnt throw a fault code so its hard to track dowm.If you know anyone with a 1.8 VAG from the same era swap in theirs and see if that fixes it.It might not be the ICM but its something to look into.
 
If you have cleaned your tb it might want putting back to basic settings using vcds
 
I had idle issues when I first got my A3. I had the fuel filter replaced and it cleared the problem.
 
Do they just plug and play then? How does it trigger the coil?
 
Yeah just plug and play, the TSi/FSi coils don't require an external ignition module, I assume it's built into each coil
 
Oh I see. That looks pretty cool.

Did you buy certain type TSI/FSI coils or just any as I did see someone suggesting there were specific coil part numbers to buy?
 
Hello guys, I am struggling with this awful idle issue on my 1998 A3 1.8T.. I have tried unplugging the MAF, cleaning the TB, resetting the TB, replacing vacuum hose, checking all other hoses for leaks/splits etc. Still the problem persists.

The car will hunt for a few seconds then settle down, however if I coast along with the clutch pressed down, the hunting will continue until I come to a standstill!?

[YT]]Idle - YouTube[/YT]




Any help or ideas would be appreciated.

Now then...... had exact same issue, try looking at the breather valve under the inlet manifold, if its passing its pulling unmetered air direct into the inlet manifold, thus a lump idle mine was sorted straight away with this, bout £8 from the dealers so very cheap fix

let me know how ya get on
 
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I have had my A3 for a little over a month now, and have had exactly the same symptoms as you with the hunting idle when pulling to a stop. Until Saturday when it stalled after starting, and after getting it going - it sounded like crap. Turns out the spark plug in cylinder 3 is wet and doesn't seem to be firing.

From what I've read on other threads, its either the coil pack itself, the Ignition Control Module, or the wiring from the ICM to the coil at fault. I am yet to find out which it is!

Have ordered a code scanner which should arrive tomorrow to see if there is anything showing before I start replacing bits!

Hope yours isn't about to do the same as mine lol. :)
 
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Ok so I replaced all the spark plugs today to bosch 509's. Still didnt fix the idle. Whilst doing the plugs I found this...

Uploadfromtaptalk1389544883848

Uploadfromtaptalk1389544904455

Any ideas what this hose is and if it would cause this hunting idle issue?

Also one of the coil packs had a bit of an oil leak?

Thanks
 
Problem solved! Cleaned the TB again today... very thoroughly. I also unplugged it, disconnected the battery then put it all back together, reconnected the battery, turned ignition on until throttle body stopped "buzzing", fired it up and joy! Idle is fixed. The new plugs and fixed idle has transformed the car. Thanks for all your input :)
 
Problem solved! Cleaned the TB again today... very thoroughly. I also unplugged it, disconnected the battery then put it all back together, reconnected the battery, turned ignition on until throttle body stopped "buzzing", fired it up and joy! Idle is fixed. The new plugs and fixed idle has transformed the car. Thanks for all your input :)
always do the free stuff first!At least its fixed
 
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Sorry to bump a week old thread, but interesting that your needle moves a tiny tiny amount, as mine does. I thought this might be a VAC leak, but have done all the above re TB, plugs, etc and it's no different. Car runs fine!

Yeah it has always done this. Whilst doing the TB I noticed a hose near the bulkhead had been rubbing on some insulation and has a small hole in it! I'm guessing this could be why the needle moves a tiny bit and maybe why I get a hissing noise under heavy acceleration? Do you get the hissing aswel?
 
No hissing (loud enough to hear, anyway) but intend on replacing most of the vac hoses anyway, just as preventative maintenance.
 
No hissing (loud enough to hear, anyway) but intend on replacing most of the vac hoses anyway, just as preventative maintenance.

Yeah good idea, I did replace my vac hose when I fitted the forge 007p... I actually think its the new recirc valve causing the hissing, it also whooshes on a gear change which is kind of crap... not sure if its supposed to or what!
 

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