Misfire cyl 3 2.0tfsi

[quattrolyf]

I’m getting a misfire randomly but mostly at idle and only cylinder 3. Tried swapping over coil packs and spark plugs but misfire stays at 3. I’ve put a new pcv on, looked for leaks,new valve cover gasket, cleaned the maf sensor and put an injector clean additive in the tank just to try. I’m thinking it might be an injector causing this or maybe a vacuum leak somewhere. Anyone have experience of something similar, I’d really appreciate the help. Also how bad is it to drive it like this? It drives fine but idle is rough but rpms stay even. I need it to get to work so I don’t have much choice than to drive it like this until I figure it out. Thanks !

[quattrolyf]

Also I get no fault codes, I only found the misfiring when checking misfire count with OBDeleven.

[Jeevan]

use a boroscope and check for carbon buildup. Also check for excessive fuel due to stuck open injector.


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[quattrolyf]

Did the carbon cleaning job and the idle is a little smoother and fuel consumption seems to have improved. However it’s still slightly shaky at idle and misfires once very minute or so. Checked the spark plugs again and they looked pretty bad so I’ve ordered new ones to make sure it’s not just a bad plug. Long term fuel trim is at 9% and short term at idle is between -2.5 and 3.5


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[quattrolyf]

Well spark plugs did nothing. Changed fuel filter too since I had one laying around and that also didn’t improve anything


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[Cyrik]

Did the carbon cleaning job and the idle is a little smoother and fuel consumption seems to have improved. However it’s still slightly shaky at idle and misfires once very minute or so. Checked the spark plugs again and they looked pretty bad so I’ve ordered new ones to make sure it’s not just a bad plug. Long term fuel trim is at 9% and short term at idle is between -2.5 and 3.5

check the wiring connecting to your coil packs, it's easy to rule that out.

How did you do your carbon cleaning service? that stuff you buy in a bottle won't do shit (you gotta take off the intake manifold for this one, also gives you a chance to look at injectors too)

What gap are you using for spark plugs?

[quattrolyf]

Hadn’t thought about that thanks!

I did take the manifold off and manually cleaned the valves with valve cleaner, brake cleaner and brushes. Got it pretty clean, had a lot of build up on the valves. Put a new gasket on the manifold too. I didn’t know how to even check the injectors and at the time I was just worrying about even getting everything back together lol. Stupid of me, now I might have to take it off again.

Spark plugs have a 7 mm gap. Had the same on the old plugs too back when I didn’t have this issue. And from what I’ve read that’s standard with a stock car.


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[quattrolyf]

I’ve checked for misfires when driving but I only get misfires when idling. Turning the ac on and increasing the idle rpms make it less noticeable too. You can both hear and feel the misfires when sitting in the car, really annoying.


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[mriddell]

What’s the engine code ?
CAED, CPMA ??
Spark plug model? I’m assuming you meant 0.7mm gap.
When you compare the spark plugs out of the engine, is white or black/ wet or dry.
Proper torque (28nM) I’ve found to be an issue too. Make sure they are clean and dry, do not use any seize on the threads.

Fuel injectors are well know for misfire issues too. I do mine every 100,000km regardless.
I just did my neighbour’s Tiguan that has 160,000km, misfire gone!
I’ve also seen the cam timing sensor cause issues, has it ever been updated?
Do you have the latest PCV ? ... I’ve read this too, but never seem for myself.


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[Cyrik]

Hadn’t thought about that thanks!

I did take the manifold off and manually cleaned the valves with valve cleaner, brake cleaner and brushes. Got it pretty clean, had a lot of build up on the valves. Put a new gasket on the manifold too. I didn’t know how to even check the injectors and at the time I was just worrying about even getting everything back together lol. Stupid of me, now I might have to take it off again.

Spark plugs have a 7 mm gap. Had the same on the old plugs too back when I didn’t have this issue. And from what I’ve read that’s standard with a stock car.

yup, 0.7mm is the correct gap for these engines on a stock car, so you're all good there 😁

Glad you did it properly with your carbon clean/removing the intake manifold, sucks you didn't think to inspect the injectors. It happens! Don't put yourself down about it! At least it's faster and easier doing it again a second time if you do think an injector is the issue 😂

Remember, you need 4 (or 3 depending who you ask) things to turn an engine: Air, Fuel, Spark, and Compression. One of those things is slightly off in your case. You can rule out spark and air, you've checked those already. Hope this simplifies things a little bit 👍

[Brillo]

To Cyrik's point, have you run a compression check across all 4 cylinders?

[quattrolyf]

IMG_8394.jpg

Anybody know why I can’t see the values of injectors ?they’re just blank. Was thinking I could check that first before removing the manifold again lol.


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[quattrolyf]

To Cyrik's point, have you run a compression check across all 4 cylinders?

I don’t have the tool for that so no I haven’t done that yet. Might have to get one


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[Brillo]

I don’t have the tool for that so no I haven’t done that yet. Might have to get one


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It's not a very expensive tool (gauge), at least here in the US. Regardless, if you have a friend who does a lot of mechanical work on their cars, they will likely have a compression gauge for you to borrow. I would suggest testing the compression before removing the manifold again.

[Theiceman]

What’s the engine code ?
CAED, CPMA ??
Spark plug model? I’m assuming you meant 0.7mm gap.
When you compare the spark plugs out of the engine, is white or black/ wet or dry.
Proper torque (28nM) I’ve found to be an issue too. Make sure they are clean and dry, do not use any seize on the threads.

Fuel injectors are well know for misfire issues too. I do mine every 100,000km regardless.
I just did my neighbour’s Tiguan that has 160,000km, misfire gone!
I’ve also seen the cam timing sensor cause issues, has it ever been updated?
Do you have the latest PCV ? ... I’ve read this too, but never seem for myself.


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typo
ummm..isnt it a B7 ?.... likely BPY or other such variant of the E113

[mriddell]

ummm..isnt it a B7 ?.... likely BPY or other such variant of the E118

... it’s why asked, I don’t see anything in the thread


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[quattrolyf]

Left it at the shop this morning to let them find the problem. Hopefully it’s something I can fix myself. Anyway check out the 1.1L beast they gave me while mine is in the shop lol almost shit myself taking a sharp turn and it felt like it was about to fall over.IMG_8406.JPG


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[Theiceman]

i'm thinking its just going to be an injector.

if it is and they decide to fix it, i would suggest putting 4 in if you plan on keeping the car , they have all had the same amount of work and the labour is virtually thee same for 4 as it is for one.

[quattrolyf]

Just got the car back, they also said it’s most likely an injector. They didn’t have any in stock so I’ll just order myself and replace it. I should probably change all 4 of them but they’re not cheap lol and I’m on a tight budget at the moment so I’ll probably get a used one. If that fixes the issue I’ll get new ones in a couple of months.


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[Theiceman]

I think there are after markets available reasonably priced. I'm sure somone will chime in.

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[quattrolyf]

All I can find here in Sweden are used OEM with high mileage, bosch or some Chinese stuff on eBay. I’m guessing the cheap eBay ones aren’t going to last long, right?


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[Cyrik]

All I can find here in Sweden are used OEM with high mileage, bosch or some Chinese stuff on eBay. I’m guessing the cheap eBay ones aren’t going to last long, right?]

unfortunately my personal experience with using ebay/non OEM parts has been terrible, I'd avoid ebay at all costs for something like this. Bosch should be the OEM supplier for injectors on the B7 platform, but used injectors might not be the worst idea from a diagnostic standpoint. (If they're known good, of course.)

I feel bad, If you lived over here in the US I would've probably sent you a used spare injector of mine.

[quattrolyf]

unfortunately my personal experience with using ebay/non OEM parts has been terrible, I'd avoid ebay at all costs for something like this. Bosch should be the OEM supplier for injectors on the B7 platform, but used injectors might not be the worst idea from a diagnostic standpoint. (If they're known good, of course.)

I feel bad, If you lived over here in the US I would've probably sent you a used spare injector of mine.

That’s nice of you, I appreciate it!
I just ordered a new Bosch injector anyway, the used OEM ones weren’t that much less expensive so at least I’ll know this one will work without any issues.
Is it a good idea to take the other ones out too and clean them while I’m at it, and is there any tips/tricks for doing so?

[Cyrik]

That’s nice of you, I appreciate it!
I just ordered a new Bosch injector anyway, the used OEM ones weren’t that much less expensive so at least I’ll know this one will work without any issues.
Is it a good idea to take the other ones out too and clean them while I’m at it, and is there any tips/tricks for doing so?

All 4 injectors should've come out when you pulled off the intake manifold :) As far as cleaning them, that's beyond my experience. But hey, that's what YouTube is for, right? 🤣 Someone else here might be able to chime in on that hopefully.

[Cyrik]

That reminds me too, as @Brillo mentioned, it would be wise to check compression before you pull off that intake manifold again, just to be sure compression isn't your root cause. Tools for this are cheap and all that's required is taking out your spark plugs, hooking up the gauge, and turning the engine over with the starter. Again it's really easy to do. 180 PSI (~12-12.5 BAR) in each cylinder is standard, but having slightly lower compression (due to the engine's age/mileage) shouldn't be an issue but they should be pretty consistent across all 4. If your compression test passes with flying colors, that injector would also be the #1 thing I would replace next.

[Jeevan]

All 4 injectors should've come out when you pulled off the intake manifold :) As far as cleaning them, that's beyond my experience. But hey, that's what YouTube is for, right? 🤣 Someone else here might be able to chime in on that hopefully.

Not always, when I carbon cleaned my valves, all the injectors were stuck in the head(yes I removed intake manifold). Saved me from buying new seals. Some people get a couple, some 1, some none like me.

[quattrolyf]

Found this video, looks like a good diy.

https://youtu.be/HnDCbWWNjA0

[quattrolyf]

So I replaced the injector with a new one and cleaned the others, it did not fix the issue..

[quattrolyf]

I found an exhaust leak and the middle exhaust hanger was broken so at least I fixed that. Here’s exactly what had happened to mine, same leak and hanger

https://youtu.be/BgSX4Xd7kTY

[tractoman]

So I replaced the injector with a new one and cleaned the others, it did not fix the issue..

So what is the status now? Did you ever test the compression? What is the plan to correct the misfire?

[quattrolyf]

So what is the status now? Did you ever test the compression? What is the plan to correct the misfire?

I guess a compression test is next. If the compression is the problem I’ll just sell it, have had way to many problems with this car by now and I don’t wanna waste more money on it.

[quattrolyf]

Good news!
Compression was all between 185 and 200psi on all 4 cylinders.
Haven’t solved the misfire yet but at least I don’t need a new engine. I also did this when engine was cold.

[quattrolyf]

From looking at fuel trims the car is running lean but still not throwing a code. I also notice on some days when the car is cold and outside temperature is lower the misfires are way less and sometimes no misfires happen. Seems to get worse when engine is warm and outside temperature is higher. When checking misfire counts on obdeleven today I got none but the car still kind of sputters and shakes slightly like it’s misfiring.. ?!
Tried lifting the oil cap when engine was running and there was no resistance like it should if I was having a leak somewhere. Not sure where to go from here so any kind of help is much appreciated!

[Brillo]

Tried lifting the oil cap when engine was running and there was no resistance like it should if I was having a leak somewhere. Not sure where to go from here so any kind of help is much appreciated!

I'm not sure what you think you're doing with the above test but you should get some resistance. In other words, there should be some vacuum sucking the cap down onto the valve cover. Once the cap is removed the engine should run very rough. If your are not getting some resistance on the cap it would point to one of several possible problems: 1) Diaphragm tear or loss of seal around the periphery of the diaphragm. Carefully pry the cap off the PCV valve and check. 2) The valve orifice beneath the diaphragm is not sealing correctly. Clean the components beneath the diaphragm with brake cleaner. 3) The check valve at the top of the tube going from the right front side of the valve cover to the pre-turbo port is defective and leaking. That check valve should let absolutely no gas to pass from the pre-turb port into the valve cover. Replace if defective. Let us know what you find. Brillo

[quattrolyf]

So I haven't had much time to spend on my car so I've driven it like this for about a month to get to work. A few days ago it started making a woosh sound when letting off the throttle over 2k rpm. Sounds like a blow off valve, sometimes like turbo flutter. I'm thinking it's the diverter valve that's failed. Could that be causing misfires also by messing up air/fuel ratio?


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[Theiceman]

So I haven't had much time to spend on my car so I've driven it like this for about a month to get to work. A few days ago it started making a woosh sound when letting off the throttle over 2k rpm. Sounds like a blow off valve, sometimes like turbo flutter. I'm thinking it's the diverter valve that's failed. Could that be causing misfires also by messing up air/fuel ratio?


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it shouldn't, as that air has already been accounted for , that's why you should not run a pop off valve. this air that is diverted is routed back around the turbo but has been accounted for. Now if the diverter completely fails like it sounds like yours has, all bets are off, if its an early one it has a diaphragm that fails, newer revs use a piston.