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Audi A2 1.6 FSi BAD 2002 - Misfires on cylinders 1 & 2, codes 16684, 16685 & 16686 - Fixed #

Posted by Sean Murphy on January 18, 2010, 8:38 pm

Year of Manufacture *: 2002
Engine Code or CC *: BAD
( Optional ) Scanner Used: VCDS

Have an A2 in with an EML lit and the following VCDS (VagCom) codes:

16684 (P0300) - Random Cylinder Misfire Detected
16685 (P0301) - cylinder 1 misfire detected
16686 (P0302) - cylinder 2 misfire detected

Replaced the coils on 1 & 2 with genuine Audi ones, fault still evident.
Removed & inspected/cleaned plugs, all look OK.
Swapped the spark plugs from cylinders 1 & 2 with 3 & 4, fault didnt move, stayed on cylinders 1 & 2 (so not the plugs).
Measured supply voltages and checked grounds on the ignition coil supply wires - all OK.
Visually inspected coil supply wiring for chaffing/wear - none found.
Cleaned the MAF (as i was there anyway), made no difference (as expected).
Did a compression test, all cylinders good and balanced.
Checked for air leaks, none found.
Clearing the fault lasts for about 1 minute on idle before the EML lights again with the same codes.

However, the flexi-metal pipe from the EGR valve to the exhaust manifold is blowing (split in the flexi-section) - could this cause the problem i'm seeing? Its booked in to have that pipe replaced anyway but i'm unsure as to whether this could cause a misfire in just 2 cylinders (EGR vlve is adjacent to cylinders 3 & 4 on the manifold...).

Any ideas?

Re: Audi A2 1.6FSi - Misfires Cyl 1 & 2

Posted by Pete Mutlow <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1569' width='330' height='300' border=0 style='border:none;'> on January 18, 2010, 9:33 pm, in reply to "Audi A2 1.6FSi - Misfires Cyl 1 & 2"
Peter Mutlow

Hi Sean,

How is the car running? ie is it actually mis-firing or just booked in for EML illuminating. If it is mis-firing, is it across the rev range - if so 4 gas readings might be helpful. Have you got a coil tester or something to observe a misfire? When I have something like this, I like to SEE a mis-fire.

Regards

Pete M

Re: Audi A2 1.6FSi - Misfires Cyl 1 & 2

Posted by Sean Murphy <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1788' width='330' height='300' border=0 style='border:none;'> on January 18, 2010, 10:20 pm, in reply to "Re: Audi A2 1.6FSi - Misfires Cyl 1 & 2"

Thanks Pete - i know what you're saying. It appears to be running fine, although the revs at idle arent the smoothest i've ever seen (varies by around +-50rpm). Drives OK and i cant 'feel' a misfire, just this damn light has appeared!!
I have maintained this car for a couple of years now so know it quite well and the customer looks after it and hasnt had this light till last week so its not a 'normal' situation - its something that has just appeared so something must be causing it (what i mean is i doubt it is something like the ECU needs a flash update).

We dont have a coil tester at the moment but may have to look into getting one if this carries on! I think i'll see if the EGR pipe has any effect and then get down to scoping the coil triggers to see if anything isnt quite right.

Re: Audi A2 1.6FSi - Misfires Cyl 1 & 2

Posted by Matt Booth <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=ukat3028' width='330' height='300' border=0 style='border:none;'> on January 18, 2010, 10:58 pm, in reply to "Re: Audi A2 1.6FSi - Misfires Cyl 1 & 2"
Matthew Booth

Had the same thing before. Firstly make sure it's not running on cheap fuel, the FSi likes high octane rather than supermarket fuel.

If your EGR pipe has no effect which I have a feeling it won't, I would change the MAF. I would have thought if the EGR split was that bad it would have logged an insufficient flow code by now.

Re: Audi A2 1.6FSi - Misfires Cyl 1 & 2

Posted by Kevin Apps <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT2589' width='330' height='300' border=0 style='border:none;'> on January 18, 2010, 11:40 pm, in reply to "Re: Audi A2 1.6FSi - Misfires Cyl 1 & 2"
Kevin Apps

Sean.
I would suspect the injectors. They are a known problem on BAD.
Kev.

Re: Audi A2 1.6FSi - Misfires Cyl 1 & 2

Posted by Sean Murphy <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1788' width='330' height='300' border=0 style='border:none;'> on January 19, 2010, 10:44 am, in reply to "Re: Audi A2 1.6FSi - Misfires Cyl 1 & 2"

A faulty injector did cross my mind, but would one faulty injector cause a misfire in two cylinders?

Anybody know if the injectors can be changed without removing the inlet manifold (i've done this once before to cure the manifold flap issue and its not a nice job!)?

Re: Audi A2 1.6FSi - Misfires Cyl 1 & 2

Posted by Matt Booth <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=ukat3028' width='330' height='300' border=0 style='border:none;'> on January 19, 2010, 2:31 pm, in reply to "Re: Audi A2 1.6FSi - Misfires Cyl 1 & 2"

I seem to remember that it's not possible to remove an injector without removing the manifold as they sit right in the middle of it all (Poor explanation but if you look at the position of them you'll see what I mean).

To give you a bit more explanation as to the reasoning for my suggestion...

We had a 52 plate A2 BAD with exactly the same problem. The car ran fine, no obvious misfire but had the fault codes for a misfire. Incidently it had a very slight rough idle but I think they're not as perfect as some other engines anyway. It came to us already having 2 new coils fitted elsewhere. We replaced these with a new genuine set so we knew where we were at. Same as you I checked the wiring as they suffer with this, plugs, compression etc etc. Anyway, we suggested the customer take it to Audi for their opinion and they said the head needed to come off as the compression was low (even though we had already tested and found it to be fine). At the customer's request I pulled the head off and did the usual. Put it back together and it was still the same. Fault was finally fixed when someone who had seen this before suggested the MAF. Just a shame the customer had to go through all that pain to get there.

My feeling is that it's much easier to change an airflow meter than an injector. Not a pleasent job.

Good luck!

Re: Audi A2 1.6FSi - Misfires Cyl 1 & 2

Posted by Sean Murphy <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1788' width='330' height='300' border=0 style='border:none;'> on January 19, 2010, 7:14 pm, in reply to "Re: Audi A2 1.6FSi - Misfires Cyl 1 & 2"

Hmmm, thanks Matt, seems thats something else to check, although i'm not sure why a faulty MAF would cause a misfire in just 2 cylinders, surely it would affect them all? But who knows with this engine - i think the engine code "BAD" is very appropriate

So, my plan is to renew the EGR pipe as it needs to be done anyway, see if that makes a difference, if not scope the coil triggers, if that shows nothing obvoius then onto checking/replacing MAF and then into the fuel injectors if any of that doesnt help!

I hate cars sometimes........

Re: Audi A2 1.6FSi - Misfires Cyl 1 & 2

Posted by Matt Booth <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=ukat3028' width='330' height='300' border=0 style='border:none;'> on January 19, 2010, 7:35 pm, in reply to "Re: Audi A2 1.6FSi - Misfires Cyl 1 & 2"
Matthew Booth

I know, very strange! Dunno if you've experienced it yet but the 2.0 8v petrols in the mkiv golf/beetle etc suffer a similar thing. The MAF fails with only faults code stored for misfire on 1 or 2 cylinders. Makes them run really rough though.

One day I'll log all the data off both engines and make some sense of it, if sense can be made! lol

Re: Audi A2 1.6FSi - Misfires Cyl 1 & 2

Posted by Sean Mc Gettigan <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5291' width='330' height='300' border=0 style='border:none;'> on January 20, 2010, 8:22 am, in reply to "Re: Audi A2 1.6FSi - Misfires Cyl 1 & 2"
Sean McGettigan

Sean if you remove the injectors then the bottom seal HAS to be renewed each time before refitting.
The injectors fit into a slight taper in the head and once up and running the heat 'sets' the seal against combustion pressure.
Find someone near you with an ASNU as there is a special tool to fit the seal.

If you remove them you cant just swap them over to try, they can be tested on an ASNU bench.

Hth Sean

Re: Audi A2 1.6FSi - Misfires Cyl 1 & 2 - Update

Posted by Sean Murphy <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1788' width='330' height='300' border=0 style='border:none;'> on January 28, 2010, 6:10 pm, in reply to "Re: Audi A2 1.6FSi - Misfires Cyl 1 & 2"

Well, renewed the EGR pipe Tuesday and the codes instantly vanished!! Though that was that but today it came back.... She had filled up with Sainsburys Super-Unleaded the evening before the codes came on - dont know if that could be related in any way?

The owner drove it about 45 miles and all was fine, then when going over approx 60mph the EML started to come-and-go. She dropped it back today for a quick fault scan and guess what?

16711 - Knock Sensor 1 (G61); signal too low
P0327 - 35-10- - Intermittent

16684 - Random/multiple cylinder misfire detected
P0300 - 35-10- - Intermittent

16685 - Cylinder 1; misfire detected
P0301 - 35-10- - Intermittent

16686 - Cylinder 2; misfire detected
P0302 - 35-10- - Intermittent

I hate this car! The knock sensor code is a new one - havent seen that till now. Would a faulty knock sensor trigger the misfire codes?

Popped some new plugs in it just because (wont do anything except ease my mind).

Re: Audi A2 1.6FSi - Misfires Cyl 1 & 2 - Update

Posted by Mark Carter <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1428' width='330' height='300' border=0 style='border:none;'> on January 28, 2010, 10:05 pm, in reply to "Re: Audi A2 1.6FSi - Misfires Cyl 1 & 2 - Update"
Mark Carter

What are the fuel trims doing?

Regards Mark

Modern cars, Its all wizardry and witchcraft

Re: Audi A2 1.6FSi - Misfires Cyl 1 & 2 - Update

Posted by Mark Murphy on February 9, 2010, 6:03 pm, in reply to "Re: Audi A2 1.6FSi - Misfires Cyl 1 & 2 - Update"
Message modified by board administrator February 9, 2010, 6:21 pm

Sorry for the delayed response - car has been in & out of the workshop over the past week or so.
Fuel trims look OK - additive 1.2%, multiplicative 0.8% (was reset not to long ago).

The EML now stays off for around 2-3 days at a time but is triggered as soon as the owner goes over approx 70mph. She has since switched to V-Power fuel as well as running some injector cleaner through, which although improving general performance has not cured the faults (her husbands idea).
However, the fault codes have now changed - i just get a "knock sensor 1 - signal too low" fault code, & very occassionally its accompanied by a "Random Cylinder Misfire Detected & Misfire Cylinder 1 & Cylinder 2".

I scoped the ingition timing whilst it was idling & although generally stable (say around 10 BTDC), occassionally the timing 'drops' & becomes erratic for around 5 seconds (say to around 2 BTDC) & then returns to the previous stable value. This happens randomly & quite frequently although it does not trigger the EML and the idle speed/stability is unaffected (probably the ICV compensating?).

So, next step is to replace the knock sensor and see if that cures it (my money is still on an injector fault but the owner wont cough up to replace it yet).

Re: Audi A2 1.6FSi - Misfires Cyl 1 & 2 - Update

Posted by Matthew Booth <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=ukat3028' width='330' height='300' border=0 style='border:none;'> on February 10, 2010, 12:02 am, in reply to "Re: Audi A2 1.6FSi - Misfires Cyl 1 & 2 - Update"
Matthew Booth

Knock sensors are very very rarely faulty. I have however had one's before that were loose. Make sure it's torqued correctly.

Hope you get it sorted soon, customer must be getting upset.

Re: Audi A2 1.6FSi - Misfires Cyl 1 & 2 - Update

Posted by Mark carter <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1428' width='330' height='300' border=0 style='border:none;'> on February 10, 2010, 1:06 pm, in reply to "Re: Audi A2 1.6FSi - Misfires Cyl 1 & 2 - Update"
Mark Carter

Why don't you test it, apposed to replacing it? With random misfire codes the AMM maybe to blame, have you got a scope trace that you can post? HTH

regards Mark

Modern cars, Its all wizardry and witchcraft

Re: Audi A2 1.6FSi - Misfires Cyl 1 & 2 - Update

Posted by Mark Robins <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1448' width='330' height='300' border=0 style='border:none;'> on February 15, 2010, 11:28 pm, in reply to "Re: Audi A2 1.6FSi - Misfires Cyl 1 & 2 - Update"
Mark Robins

As the ECU is looking at Crank position sensor input for misfire info could you have a fault there, plus miss timing causing engine knock?

Just a thought.

Re: Audi A2 1.6FSi - Misfires Cyl 1 & 2 - Update

Posted by john chadwick <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1524' width='330' height='300' border=0 style='border:none;'> on February 22, 2010, 6:24 pm, in reply to "Re: Audi A2 1.6FSi - Misfires Cyl 1 & 2 - Update"
John Chadwick

this might not be applicable to your fault but I recall reading some time ago about Audi fitting a sensor on the engine mounting? premature failure of the mounting fooled the system and brought up em faults === worth a look?

Re: Audi A2 1.6FSi - Misfires Cyl 1 & 2 - Update

Posted by george <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1272' width='330' height='300' border=0 style='border:none;'> on February 22, 2010, 6:43 pm, in reply to "Re: Audi A2 1.6FSi - Misfires Cyl 1 & 2 - Update"
George Rayner

it makes a change that someone else gets the nightmare jobs, thought it was just me.although not relavant to this vehicle i have had misfire codes for 1+2 with slight uneven idle,turned out to be worn keyway on crank and pulley,this upset timing slightly threw cyliner codes and could cause knock sensor code,? like i say not on same car and not sure on yours were crank pick up is, but worth checking timing related items.

Fixed #

Posted by Sean Murphy on April 6, 2010, 5:38 pm, in reply to "Audi A2 1.6 FSi BAD 2002 - Misfires on cylinders 1 & 2, codes 16684, 16685 & 16686 #"
Message modified by board administrator April 7, 2010, 2:22 pm

Forgot to post the fix

Turned out i had a broken wire on the knock sensor that was 'triggering' the misfire codes - replaced the knock sensor (precutionary measure as it looked a bit old and you have to remove the whole inlet manifold to get at it) and repaired the wiring and car now all sorted and running OK (for now....).

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