All Things MK6 R and GTI > MK6 General Area
Misfire with no EML
andyy:
I've recently developed a misfire from 3500 rpm onwards.. The car runs absolutely fine at idle and in all gears up to 3500 rpm.
At first I thought it was a bad batch of fuel (Momentum 99) but I've ruled that out due to the misfire only under load. I've got a Evoms intake, R8 coil pack and new spark plugs on order so hopefully this will resolve the issue.
There is no EML on and I have scanned using an obd2 scanner via Torque. It's booked in at a garage for a VCDS scan but if anyone has had similar issues or can offer advice it would be appreciated.
Cheers,
AJP:
--- Quote from: andyy on October 31, 2016, 02:01:39 pm ---I've recently developed a misfire from 3500 rpm onwards.. The car runs absolutely fine at idle and in all gears up to 3500 rpm.
At first I thought it was a bad batch of fuel (Momentum 99) but I've ruled that out due to the misfire only under load. I've got a Evoms intake, R8 coil pack and new spark plugs on order so hopefully this will resolve the issue.
There is no EML on and I have scanned using an obd2 scanner via Torque. It's booked in at a garage for a VCDS scan but if anyone has had similar issues or can offer advice it would be appreciated.
Cheers,
--- End quote ---
I take it there weren't any codes stored when you scanned it with Torque? Definitely get it scanned with VCDS, it's half the battle won.
Ideally you'd get a code showing a misfire on a specific cylinder, say cylinder 2. Then swap the plug on 2 with the plug on 3. Clear the codes. Get it to misfire again. Scan. If the misfire has moved to cylinder 3 it's therefore almost certainly a bad plug.
If the misfire stays on cylinder 2, do the same thing but with the coils. Swap coils 2 & 3 over, clear codes, misfire, scan, misfire on 3 points to a bad coil.
If it still stays on cylinder 2 after you've done all that, it could point to a bad injector, or a mechanical fault with the engine itself. A compression test will help.
I went through all of this and got as far as concluding it was likely to be a bad injector causing my misfires. I bought a used set off a breaker which I had refurbed by mrinjector. Seems to have done the trick. You might just be able to bang a single used injector in and fix the misfire; I figured a refurbed set of 4 made more sense to me.
Hopefully it's only a coil or plug causing your misfire though. That's much cheaper than injectors or worse. Make sure you try swapping things round before you fit any new parts - you'll know where the issue lies doing it that way. You could just fit four new plugs and four new coils but you wouldn't know exactly what failed and what you're fixing.
andyy:
--- Quote from: AJP on October 31, 2016, 07:59:46 pm ---
--- Quote from: andyy on October 31, 2016, 02:01:39 pm ---I've recently developed a misfire from 3500 rpm onwards.. The car runs absolutely fine at idle and in all gears up to 3500 rpm.
At first I thought it was a bad batch of fuel (Momentum 99) but I've ruled that out due to the misfire only under load. I've got a Evoms intake, R8 coil pack and new spark plugs on order so hopefully this will resolve the issue.
There is no EML on and I have scanned using an obd2 scanner via Torque. It's booked in at a garage for a VCDS scan but if anyone has had similar issues or can offer advice it would be appreciated.
Cheers,
--- End quote ---
I take it there weren't any codes stored when you scanned it with Torque? Definitely get it scanned with VCDS, it's half the battle won.
Ideally you'd get a code showing a misfire on a specific cylinder, say cylinder 2. Then swap the plug on 2 with the plug on 3. Clear the codes. Get it to misfire again. Scan. If the misfire has moved to cylinder 3 it's therefore almost certainly a bad plug.
If the misfire stays on cylinder 2, do the same thing but with the coils. Swap coils 2 & 3 over, clear codes, misfire, scan, misfire on 3 points to a bad coil.
If it still stays on cylinder 2 after you've done all that, it could point to a bad injector, or a mechanical fault with the engine itself. A compression test will help.
I went through all of this and got as far as concluding it was likely to be a bad injector causing my misfires. I bought a used set off a breaker which I had refurbed by mrinjector. Seems to have done the trick. You might just be able to bang a single used injector in and fix the misfire; I figured a refurbed set of 4 made more sense to me.
Hopefully it's only a coil or plug causing your misfire though. That's much cheaper than injectors or worse. Make sure you try swapping things round before you fit any new parts - you'll know where the issue lies doing it that way. You could just fit four new plugs and four new coils but you wouldn't know exactly what failed and what you're fixing.
--- End quote ---
Thanks for the reply.
No, no codes or codes pending when scanned via Torque. It's going in for a VCDS scan this week so hopefully I will get to the bottom of it!
I'm glad you got to the bottom of your issue. Did you have an EML light on at all? I don't even get a flash when it's misfiring.
MPG is absolutely fine.. in fact as I have to stay below 3500 rpm / 60 mph I'm getting around 35 to the gallon!! No smell of fuel or anything.. which has me thinking it''s *hopefully* nothing major!
I will let you know how I get on after the VCDS scan.
Only plus side is that my car is will have all the hardware for stage 1+ :D
AJP:
--- Quote from: andyy on November 01, 2016, 11:16:59 am ---
--- Quote from: AJP on October 31, 2016, 07:59:46 pm ---
--- Quote from: andyy on October 31, 2016, 02:01:39 pm ---I've recently developed a misfire from 3500 rpm onwards.. The car runs absolutely fine at idle and in all gears up to 3500 rpm.
At first I thought it was a bad batch of fuel (Momentum 99) but I've ruled that out due to the misfire only under load. I've got a Evoms intake, R8 coil pack and new spark plugs on order so hopefully this will resolve the issue.
There is no EML on and I have scanned using an obd2 scanner via Torque. It's booked in at a garage for a VCDS scan but if anyone has had similar issues or can offer advice it would be appreciated.
Cheers,
--- End quote ---
I take it there weren't any codes stored when you scanned it with Torque? Definitely get it scanned with VCDS, it's half the battle won.
Ideally you'd get a code showing a misfire on a specific cylinder, say cylinder 2. Then swap the plug on 2 with the plug on 3. Clear the codes. Get it to misfire again. Scan. If the misfire has moved to cylinder 3 it's therefore almost certainly a bad plug.
If the misfire stays on cylinder 2, do the same thing but with the coils. Swap coils 2 & 3 over, clear codes, misfire, scan, misfire on 3 points to a bad coil.
If it still stays on cylinder 2 after you've done all that, it could point to a bad injector, or a mechanical fault with the engine itself. A compression test will help.
I went through all of this and got as far as concluding it was likely to be a bad injector causing my misfires. I bought a used set off a breaker which I had refurbed by mrinjector. Seems to have done the trick. You might just be able to bang a single used injector in and fix the misfire; I figured a refurbed set of 4 made more sense to me.
Hopefully it's only a coil or plug causing your misfire though. That's much cheaper than injectors or worse. Make sure you try swapping things round before you fit any new parts - you'll know where the issue lies doing it that way. You could just fit four new plugs and four new coils but you wouldn't know exactly what failed and what you're fixing.
--- End quote ---
Thanks for the reply.
No, no codes or codes pending when scanned via Torque. It's going in for a VCDS scan this week so hopefully I will get to the bottom of it!
I'm glad you got to the bottom of your issue. Did you have an EML light on at all? I don't even get a flash when it's misfiring.
MPG is absolutely fine.. in fact as I have to stay below 3500 rpm / 60 mph I'm getting around 35 to the gallon!! No smell of fuel or anything.. which has me thinking it''s *hopefully* nothing major!
I will let you know how I get on after the VCDS scan.
Only plus side is that my car is will have all the hardware for stage 1+ :D
--- End quote ---
I eventually got a warning light, yes. At first it just misfired, then as the misfire got heavier the light would flash while it was misfiring, then the light stayed on constantly.
I think the ECU has to detect a certain amount of misfires before a fault code is stored. If the light is on you'll likely have a code, but if it isn't there's a fair chance you won't. There's a case for driving it until it stores a code so you have a better starting point for diagnosing the fault, but if the misfire is causing things to go lean it might not be advisable; maybe just fitting 4 new plugs and/or coils is a better option (after you've tried data logging).
When I first went about tackling mine I put in a set of new R8 coils and it 'fixed' the misfire, but only for a day. After 24 hours the misfire came back, and so I investigated further and ended up fitting a set of refurbed injectors. It's been running well for a good few weeks now so I'm confident it's done the trick.
If a scan with VCDS doesn't show any codes the next best thing is live data logging with VCDS. Basically you'll drive around with the laptop plugged in and any misfires (that aren't necessarily logged as fault codes) will show up in real time. This data can be saved as a file for reference. It's just a case of logging the correct parameters. In my case when I did a logging session the car decided to behave impeccably and didn't misfire once, so I was still none the wiser. At this point I was already on new plugs and coils so I turned my attention to the injectors.
gttdigoof:
The misfire on mine never showed, I believe you can deactivate misfire DTCs
I had to monitor the misfires manually (cant remember which measuring blocks to watch) although mine was easier due it being at low idle
Mine was caused by the injectors
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