Cold start misfires!

Damo S

Registered User
My car is standard and I get no cackle. I'm sending it into audi with my findings and let them sort it out. It might just be a knackered plug. Even so, with that many misfires I've asked them to inspect the piston because if it's knackered it will need a new engine like the guy above.

Needless to say Im no amused considering Ive also just had to fork out for a new clutch.
 

AlS3BE

Registered User
My car is standard and I get no cackle. I'm sending it into audi with my findings and let them sort it out. It might just be a knackered plug. Even so, with that many misfires I've asked them to inspect the piston because if it's knackered it will need a new engine like the guy above.

Needless to say Im no amused considering Ive also just had to fork out for a new clutch.

Hope you get to the bottom of it.
It would be good to see what Audi says. You should get one of those scope things to look at the piston and bore. Saw them on amazon for £10-20 and works with your phone just in case you get some BS from Audi.
 

CoffeeAndJam

Registered User
My car is standard and I get no cackle. I'm sending it into audi with my findings and let them sort it out. It might just be a knackered plug. Even so, with that many misfires I've asked them to inspect the piston because if it's knackered it will need a new engine like the guy above.

Needless to say Im no amused considering Ive also just had to fork out for a new clutch.

How many miles on your car? Was it tuned?

If it’s within warranty and stock, I’d get the pistons inspected via borescope by someone other than Audi. Have them show you the photos. If there’s damage to the pistons and cylinders like my old engine, Audi should replace it under warranty. No questions asked.

But, hopefully that’s not the case.
 

CoffeeAndJam

Registered User
Management light is cel. It’s probably good it’s not lighting up the cel but the fact it’s logging it 10-20 times across all cylinders would worry me but then I don’t know if that’s normal or not. I would say any misfire isn’t normal and should be looked into.
If misfires are worse with the remap then I would be more inclined to remove it.
Ran out of ideas what to look at now if everything checks out.
Have you tried higher octane fuel or some octane booster? One of my old cars was bad for misfires if I used normal unleaded instead of super/premium unleaded.

I’m thinking of replacing the plugs and gapping them down to to .026 to see if that helps. The tune could also just require time to adapt. I’m thinking that’s what happened after the stock tune was applied. Misfires were still apparent until two weeks went by. They started going down. Maybe the ECU just needs to adapt to the new tune.

I use nothing but the highest grade available in my state, 93 unleaded. That’s what the tune calls for. Do octane boosters really work and can they be dangerous?
 

ictus_duplo2

Registered User
My 2p. Know you have inspected it but would it not be worth changing the PCV valve and seals regardless of it looking ok? They are garbage. The duct gets damaged too.
 

AlS3BE

Registered User
I’m thinking of replacing the plugs and gapping them down to to .026 to see if that helps. The tune could also just require time to adapt. I’m thinking that’s what happened after the stock tune was applied. Misfires were still apparent until two weeks went by. They started going down. Maybe the ECU just needs to adapt to the new tune.

I use nothing but the highest grade available in my state, 93 unleaded. That’s what the tune calls for. Do octane boosters really work and can they be dangerous?

Colder plugs might help.
I used to own a jap import that needed 99/100 Ron fuel and it misfired a lot if I used 95 ron. Not everywhere has super/premium so had to use octane booster to stop it.
Can’t see it hurting trying a can or 2 in the car. The ecu can only advance/****** ignition so much with high octane fuels.
 

CoffeeAndJam

Registered User
My 2p. Know you have inspected it but would it not be worth changing the PCV valve and seals regardless of it looking ok? They are garbage. The duct gets damaged too.

Possibly. What’s it cost to get them changed, - couple hundred bucks? Might be worth it. Curious though, what’s garbage about them? Is there an upgraded one I can replace it with or just replace with another OEM garbage one?

Colder plugs might help.
I used to own a jap import that needed 99/100 Ron fuel and it misfired a lot if I used 95 ron. Not everywhere has super/premium so had to use octane booster to stop it.
Can’t see it hurting trying a can or 2 in the car. The ecu can only advance/****** ignition so much with high octane fuels.

Sounds like you’re not in the US. Not sure what US Premium 93 grade is equivalent to where you are, but that’s the highest grade available to me. Maybe I should try a booster if it doesn’t hurt and see if it helps.
 

AlS3BE

Registered User
Sounds like you’re not in the US. Not sure what US Premium 93 grade is equivalent to where you are, but that’s the highest grade available to me. Maybe I should try a booster if it doesn’t hurt and see if it helps.

In sunny Scotland mate. Can’t see how octane booster can hurt if anything with a good remap it should get you a bit more poke.
 

Damo S

Registered User
How many miles on your car? Was it tuned?

If it’s within warranty and stock, I’d get the pistons inspected via borescope by someone other than Audi. Have them show you the photos. If there’s damage to the pistons and cylinders like my old engine, Audi should replace it under warranty. No questions asked.

But, hopefully that’s not the case.

26k. The only mod is a different intercooler. I hope this doesnt cause a problem but it shouldnt, and if anything it should make it less likely to detonate with more consistent inlet temps. The garage who fitted it said there shouldnt be a problem with any warranty claims as a result.

Yes I have asked them to check for piston damage, and if they say its fine I will get a second opinion by a garage I trust just to make sure they are not lying (I dont see how its in their interest to do that though).

168 misfires on my 23 mile commute home where I didnt boot it once. At least it will be easy to see if they have actually fixed it or not when the car is returned.
 

ictus_duplo2

Registered User
Possibly. What’s it cost to get them changed, - couple hundred bucks? Might be worth it. Curious though, what’s garbage about them? Is there an upgraded one I can replace it with or just replace with another OEM garbage one?



Sounds like you’re not in the US. Not sure what US Premium 93 grade is equivalent to where you are, but that’s the highest grade available to me. Maybe I should try a booster if it doesn’t hurt and see if it helps.

Garbage was the wrong word ( Americanism's sneaking in to the Queens English. I am in the UK, no idea of cost :) ) weak point would be better. They are made of brittle plastic and can be effected by carbon and have various modes of failure. Don't know if there is a non oem replacement, think it just down to luck if you get a bad one. I have not experienced it directly but its a issue on Golfs.
 

CoffeeAndJam

Registered User
26k. The only mod is a different intercooler. I hope this doesnt cause a problem but it shouldnt, and if anything it should make it less likely to detonate with more consistent inlet temps. The garage who fitted it said there shouldnt be a problem with any warranty claims as a result.

Yes I have asked them to check for piston damage, and if they say its fine I will get a second opinion by a garage I trust just to make sure they are not lying (I dont see how its in their interest to do that though).

168 misfires on my 23 mile commute home where I didnt boot it once. At least it will be easy to see if they have actually fixed it or not when the car is returned.

Reason I don’t trust Audi so much, is Audi did a borescope test on my damaged original engine. After they did it, they told me I needed a new ECU and injectors. I did just injectors. Didn’t fix it. Had second opinion by specialist done, and their borescope showed pretty worn pistons and cylinders, which was their diagnosis for the misfires. Audi said nothing about the damage and decided it was something else. They also never showed me the photos or gave me my old injectors. Seemed pretty shady to me. The local shop also thought it was odd they didn’t say anything about the internal damage.


Garbage was the wrong word ( Americanism's sneaking in to the Queens English. I am in the UK, no idea of cost :) ) weak point would be better. They are made of brittle plastic and can be effected by carbon and have various modes of failure. Don't know if there is a non oem replacement, think it just down to luck if you get a bad one. I have not experienced it directly but its a issue on Golfs.

I also heard it was an issue on Golfs. I’ll consult with the shop I’m working with and hear what their thoughts are with replacing the PCV system. Maybe they’ve seen a few go bad first-hand.
 

Damo S

Registered User
Reason I don’t trust Audi so much, is Audi did a borescope test on my damaged original engine. After they did it, they told me I needed a new ECU and injectors. I did just injectors. Didn’t fix it. Had second opinion by specialist done, and their borescope showed pretty worn pistons and cylinders, which was their diagnosis for the misfires. Audi said nothing about the damage and decided it was something else. They also never showed me the photos or gave me my old injectors. Seemed pretty shady to me. The local shop also thought it was odd they didn’t say anything about the internal damage.

Noted. thanks. I will get a second opinion if they say there is no damage just to make sure
 

CoffeeAndJam

Registered User
Noted. thanks. I will get a second opinion if they say there is no damage just to make sure

Figure out what the issue was or make any progress?

Mine is still misfiring. Seems a little more now. Going back to the shop next week so they can see if they can replicate the issue and log it with their tools.

They asked me if the misfire counter goes up rapidly all in a row like “pop pop pop pop”. Any idea why they’d ask and if there’s a difference between a few here and there vs. bursts of misfires in a row?
 

Damo S

Registered User
Nope. It was due in yesterday for diagnosis, but the new clutch fitted a few weeks ago packed up on sunday (the newly fitted slave cylinder had failed) so it was at a different garage having that sorted out. I've booked it in for wednesday next week instead. Ideally it be done asap but that's the only day they have a courtesy car available. I just hope it hasnt damaged the piston
 

AlS3BE

Registered User
Where are you guys looking to see misfires? Vcds? Obd tool?
Was out yesterday coding a mates car and thought I check mine out. No errors for misfires, so I’m assuming any misfires is not a good thing. Mines only covered about 2500 miles. Not trying to rub it in, just saying it’s not normal to have misfires.
Strangely enough there was an error on abs for implausible signal.
 

Damo S

Registered User
OBD dongle plus Torque Pro. I havent seen real time but the "test results" option (at the end of a drive) then does a scan and the individual cylinder misfires appear at the bottom after 10 seconds or so.
 

AlS3BE

Registered User
OBD dongle plus Torque Pro. I havent seen real time but the "test results" option (at the end of a drive) then does a scan and the individual cylinder misfires appear at the bottom after 10 seconds or so.
Will give mine another bash and record live data.
Would have thought even a small misfire will be recorded as an error in the module.
 

Damo S

Registered User
well this is one of my questions to Audi about the issue i have, how can I get nearly 200 misfires in 25 mins without some kind of error being flagged up? If its obviously backing off the boost and timing to protect the engine then it should be telling me something is wrong without me having to go looking for it in depth.
 

AlS3BE

Registered User
well this is one of my questions to Audi about the issue i have, how can I get nearly 200 misfires in 25 mins without some kind of error being flagged up? If its obviously backing off the boost and timing to protect the engine then it should be telling me something is wrong without me having to go looking for it in depth.

I would have thought the ecu was smart enough to do this.
I can understand if it was 1-2 misfire that could be caused by bad fuel or A dirty plug but you guys are clocking hundreds of misfires and it’s not registered or telling you there’s something wrong.
My old Honda would light up the dash with just a few misfires.
Maybe it set to light up only if there was x amount of misfires over a certain time period or number of revolutions so you guys aren’t hitting that magic number for it to light up.
 

Damo S

Registered User
rubbish isnt it.
Btw is there any chance you can record what boost (psi) your car is running in 3rd gear (or above) when on full throttle please?
 

AlS3BE

Registered User
rubbish isnt it.
Btw is there any chance you can record what boost (psi) your car is running in 3rd gear (or above) when on full throttle please?

Can try. Don’t have vcds at the moment but I think obd11 has live data.
Just had a golf courtesy car that had this shown in the main screen which i thought would be useful in the s3.
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AlS3BE

Registered User
rubbish isnt it.
Btw is there any chance you can record what boost (psi) your car is running in 3rd gear (or above) when on full throttle please?
Tried. Very difficult to look at something else other than the road on full throttle.
Will get my mate out next time. It’s in kpa butveasiky converted to psi.
 

AlS3BE

Registered User
Roughly 35-36psi or 245-250kpa
1st and 2nd peaks about 33psi or 230kpa
I’m reading the intake manifold absolute pressure
 

AlS3BE

Registered User
weird, I believe they are supposed to run 18, 19 ish (or there abouts).

That’s worrying if I’m boosting twice as much. Don’t think I’m making that much power. I don’t even have the mtm box plugged in at the moment.
This was reading live using obd11. Was definitely over 240 kpa at points. Peak boost was around 5000rpm and tales off to about 190-200kpa after that.
 

AlS3BE

Registered User
Just figured it out.
Map sensor reads roughly 100kpa over what you will see in a boost gauge as it cannot read zero or negative pressure. So my readings should be close to 150kpa which is about 20-21psi
 

Damo S

Registered User
Bit of an update on mine: They have tried a plug, coil pack, new injector and none of it fixed the problem. Apparently the compression test on the engine was fine, bore scope revealed all was good (although see point above by coffeeAndjam re lies / ignorance). So they are down to "internals" and potentially removing rocker cover and cylinder head. Maybe they suspect a valve is buggered although I don't see how that would cause a misfire.
It's all a bit odd.

Look's like I'll be in the A5 for a while yet....
 

CoffeeAndJam

Registered User
Bit of an update on mine: They have tried a plug, coil pack, new injector and none of it fixed the problem. Apparently the compression test on the engine was fine, bore scope revealed all was good (although see point above by coffeeAndjam re lies / ignorance). So they are down to "internals" and potentially removing rocker cover and cylinder head. Maybe they suspect a valve is buggered although I don't see how that would cause a misfire.
It's all a bit odd.

Look's like I'll be in the A5 for a while yet....

You should still get a borescope done from another shop just to be sure.

I’d be curious to see what they find out.

Update on mine:

The shop who replaced my engine kept the car for a day and overnight and did some VCDS logging. They sent in the log files to APR and an Audi engineer to check out the data. They both said all is within spec and everything looked normal so they told me to enjoy the car and not to worry about the random misfires since the amount my car is getting is normal for an aggressive tune.
 

CoffeeAndJam

Registered User
Bit of an update on mine: They have tried a plug, coil pack, new injector and none of it fixed the problem. Apparently the compression test on the engine was fine, bore scope revealed all was good (although see point above by coffeeAndjam re lies / ignorance). So they are down to "internals" and potentially removing rocker cover and cylinder head. Maybe they suspect a valve is buggered although I don't see how that would cause a misfire.
It's all a bit odd.

Look's like I'll be in the A5 for a while yet....

Hey @Damo S, any update on your issue? How was the A5? I was loaned the supercharged version once. It was nice, loved the instant throttle response.
 

Damo S

Registered User
Hey @Damo S, any update on your issue? .

Yes there is. when they took it apart they found 1) a rogue (not an engine) bolt lodged in the head and 2) A chunk of the head casing also missing. One of the 2 has been rattling around in the head and mangled the cam shaft lobes on cylinder number 1. They dont know where the rogue bolt has come from but it appears to have got in via the oil filler cap. Whether it was in some oil that was used to top up or perhaps whilst the filler cap was off it pinged from somewhere and just happened to land in it, we can only speculate.

This causes a problem for the warranty because of the rogue bolt, so the warranty people will just tell me to get lost as its not component failure. In terms of the car, that oil filler cap has not been off during my ownership. Its not had an oil change since purchase and has not been topped up either. I need to go to the garage this week to discuss the next step. My argument is that it must have been there since before I bought the car from them, and I don't expect to be paying out any money even if the warranty people wont cover it. I can see this getting messy. Given that Ive already had to fork out for a new clutch I've told them I'm far from happy. The bill is looking at being around 4 grand.
 

AlS3BE

Registered User
Yes there is. when they took it apart they found 1) a rogue (not an engine) bolt lodged in the head and 2) A chunk of the head casing also missing. One of the 2 has been rattling around in the head and mangled the cam shaft lobes on cylinder number 1. They dont know where the rogue bolt has come from but it appears to have got in via the oil filler cap. Whether it was in some oil that was used to top up or perhaps whilst the filler cap was off it pinged from somewhere and just happened to land in it, we can only speculate.

This causes a problem for the warranty because of the rogue bolt, so the warranty people will just tell me to get lost as its not component failure. In terms of the car, that oil filler cap has not been off during my ownership. Its not had an oil change since purchase and has not been topped up either. I need to go to the garage this week to discuss the next step. My argument is that it must have been there since before I bought the car from them, and I don't expect to be paying out any money even if the warranty people wont cover it. I can see this getting messy. Given that Ive already had to fork out for a new clutch I've told them I'm far from happy. The bill is looking at being around 4 grand.

Wow!!
Hope you get this sorted. It’s gonna be a difficult one to prove.
 

Damo S

Registered User
Yes. If the car had been serviced since purchase then it would be impossible to lay the blame on them, but as it hasnt and the fact Ive only had the car a few months then they should cover it even if the warranty people don't. They ****** well should do anyway. whats the point of buying an audi approved vehicle at a premium if the "warranty" if it doesnt cover it (or the failed clutch). Its not like it will cost them 4 grand which is their retail price with their profit margin included. Im sure they made a good several grand on the sale of the car to me in the first place. T hey have been good so far but this might end up being different.
 

AlS3BE

Registered User
If it’s only been a few months are you not in a good position to reject the car. The dealers will always try and avoid this.
Could someone mucked up when you got your clutch done and that’s where the mysterious bolt came from?
 

Damo S

Registered User
If it’s only been a few months are you not in a good position to reject the car. The dealers will always try and avoid this.
Could someone mucked up when you got your clutch done and that’s where the mysterious bolt came from?

I just want it to be fixed and not expecting to reject it plus Ive now spent money on the clutch and intercooler which I wouldnt get back. The car was playing up before any work was done, plus for that job there would be no reason to take off the oil filler cap.
 

CoffeeAndJam

Registered User
Yes there is. when they took it apart they found 1) a rogue (not an engine) bolt lodged in the head and 2) A chunk of the head casing also missing. One of the 2 has been rattling around in the head and mangled the cam shaft lobes on cylinder number 1. They dont know where the rogue bolt has come from but it appears to have got in via the oil filler cap. Whether it was in some oil that was used to top up or perhaps whilst the filler cap was off it pinged from somewhere and just happened to land in it, we can only speculate.

This causes a problem for the warranty because of the rogue bolt, so the warranty people will just tell me to get lost as its not component failure. In terms of the car, that oil filler cap has not been off during my ownership. Its not had an oil change since purchase and has not been topped up either. I need to go to the garage this week to discuss the next step. My argument is that it must have been there since before I bought the car from them, and I don't expect to be paying out any money even if the warranty people wont cover it. I can see this getting messy. Given that Ive already had to fork out for a new clutch I've told them I'm far from happy. The bill is looking at being around 4 grand.

Wow, that’s worse than I was expecting to hear, I’m sorry. Sounds like you are going through some pain with your car much like I have. At least they were able to actually find what was causing it on your engine, unlike mine where the pistons mysteriously got damaged and I had to buy a whole new engine (I guess it could’ve been the tune but no one can prove it).

What does the 4 grand repair consist of them doing IF you had to pay, which it sounds like you shouldn’t.

Did you buy your car new or used? If used, it sounds like it came with some sort of warranty?
 

Damo S

Registered User
It's an "audi approved" used vehicle with a years extended "warranty". A warranty repair would consist of a completely new head and cam shafts to make it as new. A non warranty repair consists of smoothing the superficial damage to the head and replacing one of the camshaft, runners, and some seals and some plastic casing on part of the head: 5.5k versus 4k.

They have now said they will not do a warranty claim because its not component failure, which will be rejected. So the car will be getting the 4k fix and in the mean time working out who will pay. Fortunately the sales of good act 2015 is in my favour here. If the problem is reported within 6 months of purchase the onus is on the seller to prove the problem didnt exist at time of purchase, i.e. the car was fit for purpose at the point of sale. I can prove this issue certainly existed before I had any work done on the car mid november, otherwise nothing has been touched since the last service prior to purchase .... done by Cambridge Audi (vindis), who are notoriously a bunch of clowns with a bad reputation so I should have blooming guessed they would have been involved somewhere along the way.

They have already said about reducing labour rates on the bill to help me out. Its looking like I will have to pay something initially to get the car back, but my end goal is to pay nothing even if it means going to court.
 

AlS3BE

Registered User
It's an "audi approved" used vehicle with a years extended "warranty". A warranty repair would consist of a completely new head and cam shafts to make it as new. A non warranty repair consists of smoothing the superficial damage to the head and replacing one of the camshaft, runners, and some seals and some plastic casing on part of the head: 5.5k versus 4k.

They have now said they will not do a warranty claim because its not component failure, which will be rejected. So the car will be getting the 4k fix and in the mean time working out who will pay. Fortunately the sales of good act 2015 is in my favour here. If the problem is reported within 6 months of purchase the onus is on the seller to prove the problem didnt exist at time of purchase, i.e. the car was fit for purpose at the point of sale. I can prove this issue certainly existed before I had any work done on the car mid november, otherwise nothing has been touched since the last service prior to purchase .... done by Cambridge Audi (vindis), who are notoriously a bunch of clowns with a bad reputation so I should have blooming guessed they would have been involved somewhere along the way.

They have already said about reducing labour rates on the bill to help me out. Its looking like I will have to pay something initially to get the car back, but my end goal is to pay nothing even if it means going to court.

Have you got pictures?
Just curious what this stray bolt looks like. Maybe someone here looks at it and go ahhh that’s the xxxx bolt for something.
 

Damo S

Registered User
No, but I have seen it. I went to look at the damage yesterday and had quite a long chat with the chief technician about the car. It does look like an engine bolt / bracket bolt of some kind but is not a bodywork panel bolt as its not painted. Its taken a bit of a beating, and every bolt in the immediate area has been accounted for.
It doesn't really matter though as it definitely has not come from inside the head. Beyond that anything else is pure speculation.
One explanation is that it got in through the oil filler hole, that's the only way in to that part of the head for something that size.
Its also possible that it's been in their since manufacture and the very very slightly buffed cam just wasnt bad enough to cause a noticable problem but over time the constant wear caused by the abrasion on the cam has made the problem progress. It has got a bit worse during my 5k miles of driving, but not that much worse and was still intermittent requiring the right conditions to show itself even just before it went in.
It is possible it was like that from new but perhaps not bad enough initially for the first owner to notice over their 20k miles of driving. Considering how relatively subtle the problem is, I now believe this is the most likely cause, and way more likely than a random bolt pinging off and just happening to land through an open oil filler.
Even in its current state the ECU is able to alter timings etc around it and trim the engine to run without registering a misfire for some time. The tech was amazed at how the engine was able to run more or less normally considering there is some abrasion to the cam lobe.
 
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