Injector misfire help K04

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Uber-A3

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I have been getting misfires on my K04 upgraded 2007 A3. It doesn't set an engine fault code but the car is misfiring above 5.5k in 3rd gear and up. I am sure it is fuel related because I have swapped out new coils and new plugs with no difference. I have done countless logs with VAGCOM and I get misfires on all cylinders at different times. I have been reading on here about people chipped the S3 and the injectors causing misfires. Do people with this problem experience misfires on just the cylinders where the injectors are bad or do the injectors all go bad?

I have done compression test and boost leak test and everything is normal. Tank pump and fuel filter have been replaced with updated versions. Car runs fine until the upper revs and does it much worse when the weather is cold or increased load like a hill. I think this is due the increase in fuel that is requested. Car runs brilliant with stock map. Car has 37,000 miles

Here are mods:
2.0t fsi S3 K04
S3 Injectors
APR hpfp
Carbonio Intake
APR tune
APR DP
Milltek exhaust
302 whp
 
You need to get it back on the rolling road and check the AFR, it could be a rich mis-fire or it could be running out of fuel.

I would certainly get the people who remapped it for the S3 injectors to have another look at it.
 
RobinA3 said:
You need to get it back on the rolling road and check the AFR, it could be a rich mis-fire or it could be running out of fuel.

I would certainly get the people who remapped it for the S3 injectors to have another look at it.
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The car has ran perfect for the last 20k miles so the problem is not the map. It is running at the requested lambada of .73 which is rich.
 
audi upgrades
If this was an old school car

I would of said HT leads or plugs!!

so coil packs or spark plugs is your fix mate as your spark is weak and blowing out at high rev's high compression.

Do the plugs first as cheaper, you say you have 37k miles so when were plugs last changed or car serviced as this may help the answer?

Gaz
 
gaz m said:
If this was an old school car

I would of said HT leads or plugs!!

so coil packs or spark plugs is your fix mate as your spark is weak and blowing out at high rev's high compression.

Do the plugs first as cheaper, you say you have 37k miles so when were plugs last changed or car serviced as this may help the answer?

Gaz
Click to expand...

Plgs and coils are both brand new. Oem bosch pplugs and brand new coils with part numbers that Audi say are good versions. I even swapped coils with a brand new set of Okada coils and it does the exact same thing.

The only things I am down to to is either intake valve deposits, injectors, or the camshaft is about to fail. It is just hard to diagnosis because there is no engine light to direct me.
 
I would contact APR directly and ask them to help you diagnose the problem. I am sure they will be willing to help you out as from what I have seen their aftersales support is very good.
 
KRL said:
I would contact APR directly and ask them to help you diagnose the problem. I am sure they will be willing to help you out as from what I have seen their aftersales support is very good.
Click to expand...

They have been helping but we have kind of hit a dead end. I have sent logs but nothing stands out they say. I am going to pull the manifold and clean the valves, it needs to be done either way and hopefully it cures the problem. I find it hard to believe that all 4 injectors went bad at the same time.
 
I would go back to the plugs again mate check there condition, sooty deposits etc this will possibly show up the cylinder that is playing up? be it fuel, spark or some other cause, lean or rich fuel mixture. Even brand new plugs fail especialy if the gaps were wrong?

If you dont know what your looking at on the plugs stick a photo up and I will have a look but mark the cylinder they come from.

Cheers Gaz
 
Uber-A3 said:
They have been helping but we have kind of hit a dead end. I have sent logs but nothing stands out they say. I am going to pull the manifold and clean the valves, it needs to be done either way and hopefully it cures the problem. I find it hard to believe that all 4 injectors went bad at the same time.
Click to expand...

I'll be interested to see what your valves look like so would you mind taking some pics and posting them up if you can?
 
I had a similar issue, so changed my plugs and replaced with a the same issue to OEM Bosch and still had the problem

Changed to NGK Iridiums and voila, problem solved. Two steps cooler and never another hesitation issue since.
 
Yep that would help Warren

Which is why I was after seeing a pic of the plugs, It will still help if you can take some Uber A3.

Gaz
 
Plug on left: Bosch OEM (10k miles - knackered, car stuttering at over 5k rpm)

Plug in middle: NGK Iridium BKR6EIX (20k miles, changed as running way too hot)

Plug on right: NGK Iridium BKR8EIX (new, 2 steps cooler waiting to go in, fine ever since)

Look at the difference in the sizes of the ceramic collars between each plug

DSC_0017.JPG
 
if you are chipped you should also drop the plug gap to .7mm, prevents spark blow out at high boost/revs
 
gapping, now l was told this but not lot of people know how to.
 
I wouldn't want to gap a plug myself, I'd get someone experienced to do it. Be frightened of damaging the tip.
 
Well cleaned the valves and just to rule it out threw in brand new NGK BKR7EIX plugs. Problem is still exactly the same, getting misfires on all cylinders at different times. Only in performance map and only 3rd gear and up above 5.5k rpms. The quest continues.
 
I would say filter looks like next port of call. I had the Carbonia, and it as soon as I changed to CAI things improved. Rather than go out and buy one ddo you know anyone local to you in a club who could loan you a unit to test??

Fuel injectors do seem to be a bit of an issue. Wonder if it is spray pattern, or whether with mods we make it adjust things so much it affects the running parameters too much for fuel stratified process (meaning anything other than optimal running conditions throw up curveballs). I have a misfire in cylinder 3 (only) consistently, and whilst I still have good power it I cant see why it should happen. No fault codes at all????

Problem is you spend money blindly and you may never get back to the root cause of the issue.

These things get harder to diagnose all the time.
 
Last edited:
warrencox said:
I would say filter looks like next port of call. I had the Carbonia, and it as soon as I changed to CAI things improved. Rather than go out and buy one ddo you know anyone local to you in a club who could loan you a unit to test??

Fuel injectors do seem to be a bit of an issue. Wonder if it is spray pattern, or whether with mods we make it adjust things so much it affects the running parameters too much for fuel stratified process (meaning anything other than optimal running conditions throw up curveballs). I have a misfire in cylinder 3 (only) consistently, and whilst I still have good power it I cant see why it should happen. No fault codes at all????

Problem is you spend money blindly and you may never get back to the root cause of the issue.

These things get harder to diagnose all the time.
Click to expand...

Fuel filter is brand new and fuel logs look good. Carbonio intake is the only one that will work with APR map, all the other people have tried set MAF fault codes. I found this out when I tried to fit one 2 years ago.

Just to try something I unplugged the primary 02 sensor and the misfire goes away. Now I am not sure if this is because the 02 is sending incorrect information or because it is running in open loop. I'll need to log injector timing and see what it looks like.

Without fault codes,your right, this thing is hard to chase down.
 
May sound silly, but have you checked the fuel pump follower? Could even be a bad seal on the oil cap or dipstick tube. There have been a few issues with injectors failing, but this is usually only one or two rather than all four.
 
IbizaAlex said:
May sound silly, but have you checked the fuel pump follower? Could even be a bad seal on the oil cap or dipstick tube. There have been a few issues with injectors failing, but this is usually only one or two rather than all four.
Click to expand...
I replaced the follower about 3k miles ago and rechecked it when this started. I also doubt that all 4 injectors started acting up at once. I am going to try a friend's 02 and see what that does.
 
Well tried a buddy's 02 sensor and the problem came back. So now I know it was running fine due to it running in open loop.
 
Did you workout what the cause is?

I have the same problem and I believe it may be the injectors.
 
Hey guys, I have the same issue, from 4800rpm all the way to 6500rpm.
Car has a full K04 kit with APR HPFP and REVO Stage 3 software.
I am running one set colder plugs as well as the RS4 low fuel pressure regulator but still can not solve the issue.
Intake pump does not dip below 4.1 bar and rail pressures not below 127 bar.
no errors either.
One thing for certain is that the airflow is rather low, gets to 201g's at 4800rpm and maxs at about 206g's at 6500rpm. So does not really climb.
NB: I am in South Africa and at Altitude!!
PLEASE HELP, I am dumb struck!!!
 
JojoZA said:
Hey guys, I have the same issue, from 4800rpm all the way to 6500rpm.
Car has a full K04 kit with APR HPFP and REVO Stage 3 software.
I am running one set colder plugs as well as the RS4 low fuel pressure regulator but still can not solve the issue.
Intake pump does not dip below 4.1 bar and rail pressures not below 127 bar.
no errors either.
One thing for certain is that the airflow is rather low, gets to 201g's at 4800rpm and maxs at about 206g's at 6500rpm. So does not really climb.
NB: I am in South Africa and at Altitude!!
PLEASE HELP, I am dumb struck!!!
Click to expand...

What CAI (intake) are you using?
 
Im in the same boat ( only saw this after i posted mine a few further up)


07 22k S3
Stage 2+ software
Autotech HPFP
RS4 Fuel pressure regulator v/v
THS intercooler
Denso Iridium IK24 plugs
Milltek TBE
EVOMS intake
 
The Op in this thread was using a Carbonio intake,and I don't know what JoJoZa is using,but airflow may well be a problem here.

I tried using the stock system for mine,which is not a whole lot worse than the Carbonio,as it also uses the same panel filter and most of the OEM trunking.
The misfire on mine was directly related to the system strangling airflow at peak power,and causing a nasty misfire.

Changing to a Forge system cured it immediately.
 
Hi
Sorry, been away.
Changed plugs yet again and has helped to a small extent, still there but not as bad that is the cutting out.
I am using the NGK BCP7RES.
Still struggles to rev cleanly from 5000rpm though imo, airflow still low!!!
CAI, I am using the tried and tested first gen Forge Intakes!!! has worked the best for me, maybe time for a change?
Could it be coil packs on the way out? Seeing that plugs assisted somewhat?
 
Im still convinced these types of misfire is caused by valve float. My car is booked in at Revo HQ on the 8th for some data logging and to try get to the root cause of this problem. I'll keep you posted.
 
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