'99 Audi A3 1.8T Stuttering and slightly rough idle

[dryrun]

Hi there,

Having some problems with my '99 Audi a3 1.8 turbo with AGU engine. Intermittently the car stutters badly when pulling away and sometimes in 2nd and 3rd gear. Also sometimes when first starting up the car starts to rev, struggles then stalls. Sometimes it can do this 3 or 4 times in a row. I addition to this the idle jumps around a little bit (a hundred revs roughly)

I had diagnostics done, and it came out with P1851 and P1612, and mechanic said something about intake manifold pressure aswell.

After this i have started process of elimination, i have done filters and oil, spark plugs and tried injector cleaner

Ive had a look at related threads and im starting to think its possibly maf or ignition module, but im a bit stumped for what to do if im honest and dont want to just throw money at it.

Any advise on what to do or what the likely defective part is would be great, the stuttering is driving me nuts,

Cheers guys


Just tried starting it, it took 10 goes. Each time it started, struggled then stalled

It was horrible!

Please help

[Crasher]

Yes the ignition module on these is a common cause of misfiring. Those two fault codes are unusual and you are going to need specialist help in dealing with them so at the very least you need a proper code reading system that can perform coding value and live data functions.

18259 (P1851) CAN bus fault. Message from ABS control unit

Possible cause

Fault in the data line to the ABS control unit (antilock system)

Possible effect

No driving dynamics control

Possible remedy

Check the Motronic system/ABS/gearbox data exchange (CAN bus)


18020 (P1612) Engine control unit incorrectly encoded

Possible cause

Engine control unit incorrectly encoded

Possible effect

Loss of performance. Increased emission values. Various faults in fault memory

Possible remedy

Encode control unit

[dryrun]

Cheers crasher, im looking into finding a garage to look at codes.

Is there a way of eliminating the maf being the culprit because im worried about shelling out loads on ignition module unless im very confident about it being the problem.

In addition; when it stalls there is a loud buzzing sound inside the car,like feedback sort of sound, this mite be relevant but thought i would say.

[Crasher]

The only way of completely eliminating the Air Mass Meter as being at fault is to fit a new genuine exchnage Audi dealer supplied part and as the AMM on this engine is the only real load reference, a faulty AMM can cause problems but usually mixture related which would leave lambda codes. DO NOT buy a pattern, used or whatever AMM, genuine Audi only! My instinct would be to fit a new ignition amplifier and if this cures it, four new coil packs as I have known the amp damage the coil packs and then the damaged coil packs damage the new AMP so you end up going around in circles.

[dryrun]

Got worse this morning..... my girlfriend told me it took 30 goes to get started this morning


Yeah from what your saying im guessing it might be ignition module, and i see your point about coil packs. looks like this might be expensive .oh well its gotta be done. So im gonna go down this route after i get codes read again.


Out of interest i unplugged the maf for a while to try and understand if this was at fault, im sorry if this was stupid of me (im used to old carbs), the stalling has been worse since, coincedence?. Also i know someone who has exactly the same car that 'had' a very similar problem and it was the maf, could i do swap for abit to eliminate?

cheers

[Crasher]

The only way to eliminate the AMM is to fit a new one or a known to be good unit that is EXACTLY the same.

[dryrun]

hi guys,unfortunately the car will not even start at all. At first thougt it was battery because it was turned over so many times. So recharged battery but still no start,starter sounds strong but engine wont fire.All i can think is has all the starting,running for 2 seconds and dying has messed up the fuelling in some way,any suggestions guys?

[Crasher]

Well it is not the AMM/MAF as it will start and run with it disconnected! You may have made the plugs wet, what used to be called "flooding an engine" so first of all take them out and gently clean them or even replace and whilst out, crank the engine over to purge the bores of wet fuel but do this with the coil packs disconnected and the fuel pump fuse out.

[khuongy]

I have a 1999 8L A3 1.8T that is starting to do my head in...

I believe I am having the same problem...

My car (intermittently i might add) will violently shudder... feels like i've lost half of my engine.... idle pretty crap then stall.... likes to happen i'm in traffic...

Upto now if the car stalls... it is a simple turn of the key just to restart it get it going again.... but now... it takes ages... if it stalls, i try to start the car...it will fire...but then stall again a few seconds later.... if i leave it a few mins.... it will start up like nothing has happened....

to date... my mechanics have changed... Coils (all 4)... they said they have changed Plugs (but i'm not sure).... and we have swapped a few ignition modules already....

everytime i take in to them the problem does not occur, and scans bring up nothing except for some air fuel mixture thing....

I'm out of Idea's and i think they have no idea... they think it "maybe a crank sensor"... but starting to doubt it....

I need help... let me know if there is anything else i should try....

[Doctle Odd]

You need a proper diagnostic scan with VCDS, stop spending money until you know what you need

I have a 1999 8L A3 1.8T that is starting to do my head in...

I believe I am having the same problem...

My car (intermittently i might add) will violently shudder... feels like i've lost half of my engine.... idle pretty crap then stall.... likes to happen i'm in traffic...

Upto now if the car stalls... it is a simple turn of the key just to restart it get it going again.... but now... it takes ages... if it stalls, i try to start the car...it will fire...but then stall again a few seconds later.... if i leave it a few mins.... it will start up like nothing has happened....

to date... my mechanics have changed... Coils (all 4)... they said they have changed Plugs (but i'm not sure).... and we have swapped a few ignition modules already....

everytime i take in to them the problem does not occur, and scans bring up nothing except for some air fuel mixture thing....

I'm out of Idea's and i think they have no idea... they think it "maybe a crank sensor"... but starting to doubt it....

I need help... let me know if there is anything else i should try....