A3 1.4 TFSI 2013 cylinder 2&4 misfire. PLEASE HELP!

[audrey1989]

I really hope someone here can help me!
I was driving up the motorway over the weekend and noticed a loss in power. The local garage has ran diagnostics which has said cylinder 2&4 misfire. Copy of the report is attached.

Car is misfiring constantly at low revs and speed (I.e idle and pulling away from junctions the misfiring can be felt). At 30 mph and up, the misfiring isn’t noticeable.

The local garage has replaced the spark plugs which didn’t help. They’ve said it could be piston injector or a valve and that the engine needs to be stripped in order to find the problem, which will cost £1500.

Has anyone else came across this problem? Does anyone have any advice on how to approach/things to check before stripping the engine?

If anyone has any advice, I’d really appreciate it.

Car has 95,000 miles on the clock and there were no previous owners.

Thanks!

 

[AlS3BE]

Have you checked the coil packs?

 

[Henda]

Does your car have the Cylinder on Demand function. It could be that thats playing up?

 

[Damo S]

The local garage has replaced the spark plugs which didn’t help. They’ve said it could be piston injector or a valve and that the engine needs to be stripped in order to find the problem, which will cost £1500.

IMO it seems rather unlikely that both 2 and 4 of either pistons / injectors / valves would suddenly fail at the same time. Not impossible but unlikely. Also, if it was a physical problem such as broken pistons / valves then it would occur all the way up the rev range not just at low revs.

Seems more likely that its an electronic issue and not physical.

See this thread

https://www.audi-sport.net/xf/threa...0304-misfire-p130a-cylinder-disabling.224701/

similar issue I think and turned out to be the coil packs.

 

[audrey1989]

Have you checked the coil packs?

I believe the AA checked the coil packs when they came out. They switched the coils over and the problem always remained on cylinder 4. Cylinder 2 didn’t come up as a fault when it first broke down. It’s only since it was in the garage that, cylinder 2 is now misfiring

 

[audrey1989]

Does your car have the Cylinder on Demand function. It could be that thats playing up?

I’m not sure if it’s COD. I’m going to call Audi customer services today and see if they have any idea.

 

[audrey1989]

IMO it seems rather unlikely that both 2 and 4 of either pistons / injectors / valves would suddenly fail at the same time. Not impossible but unlikely. Also, if it was a physical problem such as broken pistons / valves then it would occur all the way up the rev range not just at low revs.

Seems more likely that its an electronic issue and not physical.

See this thread

https://www.audi-sport.net/xf/threa...0304-misfire-p130a-cylinder-disabling.224701/

similar issue I think and turned out to be the coil packs.

Strange that you should say electrical. The AA also said it was an electrical issue. However, the guy in the local garage said it was definitely mechanical. But as far as I know, all he did was plug the diagnostics computer in and change the spark plugs.

The AA swapped the coils over and the problem remained on cylinder 4. Cylinder 2 was not an issue at first. Cylinder 2 only started being an issue when the local garage ran the diagnostics.

What things do I need to look for to tell if it’s electrical?

 

[AlS3BE]

Strange that you should say electrical. The AA also said it was an electrical issue. However, the guy in the local garage said it was definitely mechanical. But as far as I know, all he did was plug the diagnostics computer in and change the spark plugs.

The AA swapped the coils over and the problem remained on cylinder 4. Cylinder 2 was not an issue at first. Cylinder 2 only started being an issue when the local garage ran the diagnostics.

What things do I need to look for to tell if it’s electrical?

Check for broken wires, bad corroded earth points and broken pins on connectors. These are the simple to check first.
Next(maybe) swap injectors between cylinders to rule them out.
Before ripping the head off I would do a compression test on all cylinders and see if they are up to spec and fairly even across all.
All this is fairly cheap to do at a garage or do it yourself before spending big bucks in ripping engine apart.

 

[audrey1989]

Check for broken wires, bad corroded earth points and broken pins on connectors. These are the simple to check first.
Next(maybe) swap injectors between cylinders to rule them out.
Before ripping the head off I would do a compression test on all cylinders and see if they are up to spec and fairly even across all.
All this is fairly cheap to do at a garage or do it yourself before spending big bucks in ripping engine apart.

The local garage has done a compression test. Sorry should have mentioned in the original post. They said the first time they tested cylinder 4 the compression was low and the second time it was significantly lower and that cylinder 2 was also low.

 

[AlS3BE]

The local garage has done a compression test. Sorry should have mentioned in the original post. They said the first time they tested cylinder 4 the compression was low and the second time it was significantly lower and that cylinder 2 was also low.

That’s probably not a good sign. Piston rings/ valves, could be quite bad and expensive.

 

[audrey1989]

That’s probably not a good sign. Piston rings/ valves, could be quite bad and expensive.

What kind of cost am I looking at for those, excluding labour?

 

[AlS3BE]

What kind of cost am I looking at for those, excluding labour?

Don’t know. All I know Audi parts are not cheap.
Hope you get it sorted
Only other thing I can think of is sticking valves might cause the same symptoms. Could try an engine flush for all it’s worth.

 

[Damo S]

The local garage has done a compression test. Sorry should have mentioned in the original post. They said the first time they tested cylinder 4 the compression was low and the second time it was significantly lower and that cylinder 2 was also low.

Oh wow, that seems really incredibly unlucky to have 2 go in that way. Looks like an engine strip may be the only option then. alternatively, hunt out a recon / 2nd hand engine and just swap it over since that may not be any more expensive than the cost of stripping yours down and fixing.

 

[AlS3BE]

Out of curiosity for those in the know. Which cylinders get shut off for COD?
Reason I’m asking is if same 2 cylinders gets shut off and there’s residual fuel in them you would get bore wash and they will wear quicker than the ones that gets fired. Also they will be cooler and oil won’t flow as freely around them.
Might be just me over thinking it but in my head the COD could be more problematic than it’s worth more so on a turbocharged engine.

 

[cuke2u]

We get one occurrence of this, despite COD technology being in thousands of cars, and suddenly you 'feel' it's the technology at fault.
Really???

 

[AlS3BE]

We get one occurrence of this, despite COD technology being in thousands of cars, and suddenly you 'feel' it's the technology at fault.
Really???

Just curious more than anything. Like all tech they are bad before they are good. Just look at early smartphones before the iPhone.
This COD thing is something that’s gonna appear in most cars till electric cars take over so trying to see how it all works.

 

[wab172uk]

I really hope someone here can help me!
I was driving up the motorway over the weekend and noticed a loss in power. The local garage has ran diagnostics which has said cylinder 2&4 misfire. Copy of the report is attached.

Car is misfiring constantly at low revs and speed (I.e idle and pulling away from junctions the misfiring can be felt). At 30 mph and up, the misfiring isn’t noticeable.

The local garage has replaced the spark plugs which didn’t help. They’ve said it could be piston injector or a valve and that the engine needs to be stripped in order to find the problem, which will cost £1500.

Has anyone else came across this problem? Does anyone have any advice on how to approach/things to check before stripping the engine?

If anyone has any advice, I’d really appreciate it.

Car has 95,000 miles on the clock and there were no previous owners.

Thanks!

Could be a faulty injector / injectors which then cause the Piston to disintegrate. If that's the case, your F****d. New engine required !!!!

 

[audrey1989]

The local garage fit new spark plugs on Monday. Since then the car has been driven 3 miles to my friends dads house who is a retired mechanic. As you can see in the pic, plugs 1,2&3 look like they’ve been firing whereas number 4 looks untouched. The ignition coil for number 4 was also damaged. The plug cap (the rubber bit on the bottom) was split and came apart. I don’t have a picture of this. We are waiting for a compression tester to be delivered before proceeding further.

 

[Mikeso51]

Out of curiosity for those in the know. Which cylinders get shut off for COD?

COD turns off cylinders 2 and 3

 

[AJB]

Out of curiosity for those in the know. Which cylinders get shut off for COD?

2&3 (I suspect as they're in the middle so will stay a bit warmer and soak up a bit more heat from 1&4 than 1&4 would from 2&3 if they shut down 1&4. It has to be 2&3 or 1&4 so that you still get cylinders firing at a constant rate (fire, nothing, fire, nothing rather than fire, fire, nothing, nothing)).

Reason I’m asking is if same 2 cylinders gets shut off and there’s residual fuel in them you would get bore wash and they will wear quicker than the ones that gets fired.

No. They shut off at a fixed point in the cycle and the engine knows it's about to do it so can stop feeding fuel to those injectors after the last full power cycle. If there was any residual fuel (which there won't be) it'd get diluted away in no time anyway as the engine carries on rotating and splashing/squirting oil about the place.

Also they will be cooler and oil won’t flow as freely around them.

Yes they'll be cooler - the thermal cycling is going to be harder on things. Plus running at a lower temperature on restart. Oil doesn't flow around the cylinders, so that won't be relevant - it's potentially sprayed onto the back of the pistons, and splashed around the bores below the pistons, but all of the oil is at the same temperature anyway - it comes out of the sump, then goes through one pump and on to wherever.

Might be just me over thinking it but in my head the COD could be more problematic than it’s worth more so on a turbocharged engine.

Turbo or not is unrelated I think. Yes CoD is something else to go wrong or to cause problems. But I haven't yet read a single case of it failing, so they might have got it right! As to whether it's more trouble than it's worth - depends on what's worth what to each individual. The simpler the engine the more reliable it can be. But CoD gets 25% more torque IIRC whilst using no more fuel for given driving. It may even have been less fuel officially, but certainly the same tax band etc if not lower. Getting that torque/power increase by having a bigger engine or more aggressive valve timing/opening would have hit fuel costs and tax costs via CO2 rating.

 

[AJB]

The local garage fit new spark plugs on Monday. Since then the car has been driven 3 miles to my friends dads house who is a retired mechanic. As you can see in the pic, plugs 1,2&3 look like they’ve been firing whereas number 4 looks untouched. The ignition coil for number 4 was also damaged. The plug cap (the rubber bit on the bottom) was split and came apart. I don’t have a picture of this. We are waiting for a compression tester to be delivered before proceeding further.

Once the ECU knows it's got a misfire on a given cylinder, it can just stop injecting fuel to that cylinder. So the untouched plug on 4 is probably an expected symptom of a misfire on 4.

 

[audrey1989]

Compression tester arrived. Cylinders 1-3 have a compression of 175 psi, cylinder 4 is 40 psi. When the compression tester was used in the cylinder 4, water was found on the end of the tester. Right now we suspect water problems in cylinder4. We’ve just put some steel seal into the radiator and are waiting for the 30 mins quoted on the bottle to see if this fixes it.

If it does turn out to be water problems, does anyone know how much it costs to get a cylinder head replaced?

Will keep you all updated.

 

[AlS3BE]

Compression tester arrived. Cylinders 1-3 have a compression of 175 psi, cylinder 4 is 40 psi. When the compression tester was used in the cylinder 4, water was found on the end of the tester. Right now we suspect water problems in cylinder4. We’ve just put some steel seal into the radiator and are waiting for the 30 mins quoted on the bottle to see if this fixes it.

If it does turn out to be water problems, does anyone know how much it costs to get a cylinder head replaced?

Will keep you all updated.

Could just be the head gasket has gone. I’ve had older cars that the head gasket split but the head and everything else was fine. Replacing head would be expensive. Not sure what these heads are like but you should get away with a light skim if it’s slightly warped.

 

[audrey1989]

The misfire seems to have improved. Barely noticeable when driving at low revs. Before it was extremely noticeable when going up a hill or low revs going around the roundabout.
Misfire is still very noticeable when idle.

 

[audrey1989]

I’ve left the car overnight for the engine to cool down to see if the steel seal would fix the problem. Misfiring is still present but not as bad as before. Can’t get the car back in the garage till next Thursday now.

 

[audrey1989]

Just an update in case anyone else encounters this issue. I took the car to a German car specialist garage. Turns out I have a burnt valve. All in all it’s costing £1450 to repair the car which also includes a timing belt replacement, water pump replacement and a full service. I knew I was due a timing belt replacement and had enquired about two month ago as to the cost. Timing belt replacement and water pump was going to be £500 and I usually pay about £200 for a full service so I don’t mind the cost of the repair. Just relieved that it’s not more.

Thank you all for your contributions. I really appreciate it.

 

[Khufu]

a burnt valve is a bit of a worry. What fuel do you use?

 

[audrey1989]

a burnt valve is a bit of a worry. What fuel do you use?

Normal unleaded from the local shell garage. What usually causes burnt valves?

 

[AlS3BE]

Normal unleaded from the local shell garage. What usually causes burnt valves?

Normally misfiring, pinking, lean air fuel mixture. The valve is the damage but I think a little investigation as to what was the cause might be needed as it could happen again. Maybe check the injectors.
Was it an exhaust or inlet valve that was burnt?

 

[Khufu]

Our cars are designed to run on 97 but can run on 95. For that reason i prefer to use super plus to be on the safe side. I too would be wanting to know what caused it to burn out.

 

[audrey1989]

Normally misfiring, pinking, lean air fuel mixture. The valve is the damage but I think a little investigation as to what was the cause might be needed as it could happen again. Maybe check the injectors.
Was it an exhaust or inlet valve that was burnt?

It’s an exhaust valve. I’ve asked if they know what’s caused it and if there’s anything I can do to prevent it happening again in the future and they’ve said it’s just one of those things and nothing I can to prevent it.

 

[audrey1989]

Our cars are designed to run on 97 but can run on 95. For that reason i prefer to use super plus to be on the safe side. I too would be wanting to know what caused it to burn out.

Thanks for the tip. I’ll start using super unleaded too.

 

[cuke2u]

Really you're wasting your money, however if you are concerned then every 4th fill up will do...

 

[Damo S]

I've always ran my cars on tesco 99. They seem to run a little better than any other fuel and it's not that expensive.

 

[cuke2u]

The argument about about whether to use premium fuel in a vehicle in a standard state of tune has been done to death and nothing has been proven.
But yes, depending on your mileage, not much more...

 

[Khufu]

I've always ran my cars on tesco 99. They seem to run a little better than any other fuel and it's not that expensive.

i used to run my old A3 NA 2.0 fsi on that and never thought it was any better until i had to put standard fuel in. Was driving around for a few days and thinking is seemed slightly flatter than normal and then i remembered i'd put 95 in.

 

[Khufu]

The argument about about whether to use premium fuel in a vehicle in a standard state of tune has been done to death and nothing has been proven.
But yes, depending on your mileage, not much more...

i agree if a car is designed to run on 95 then anything higher is a waste if it doesnt advance the ignition timing to take advantage. We sell Gulf fuel and the Endurance 97 has extra cleaning additives over regular 95 which is also why i use it.

 

[Damo S]

Its also assuming the 95 you've put in is actually 95 and not some diluted / dirty old junk which has been sat around for a while. Never had an issue with 99 where as I have had issues with other grades including shell v power, all of which made the car feel a bit lumpy and touch flat.

IMO, for the health of the engine it is better to have fuel that is too good rather than fuel that is borderline.

 

[cuke2u]

All fuel in the uk is sold to a specific standard and is checked at refineries, tankers and garages. Irrespective of the octane they are more or less the same, some supplying companies do put in their own additives which they claim are beneficial.
Of course there will be a select few petrol stations who standards might slip, knowingly or unknowingly.
That's just life unfortunately with any product.

I have always used 95 supermarket fuel in my vehicles and never once had any issues what so ever other than ones on my wallet...

 

[Audi Ashley]

I was told by a Tanker driver for a particular band of high fuel that it all comes from the same tap. I sorta belive this becuase I have been inside a milk depot and they stick 2 labels on it, one Aldi and one Marks & Spencer, 2 different prices, same milk.