Sudden EML flashing, loss of power, bad misfire mk2 Leon FR
Discussion
Hi guys, so I was driving down some country lanes when all of a sudden my EML started flashing and the engine started missing (which obviously accompanied a loss of power). Then, as I slowed down to come to a stop the battery light also came on solid.
I know these 2.0 TFSI engines are prone to misfires and that the coil packs go on them, so that was what I originally thought was wrong, but the whole thing is kind of baffling really.
I plugged a mate’s scanner in (one of those non-professional phone ones) and it came up with cylinder 4 misfire and a bunch of door module codes. To be honest, I don’t really trust the code reader but I decided to replace the coil pack on cylinder 4 just to see of it was something simple. Originally the car would eventually cut out at idle, but after replacing the coil pack it then started to idle a bit better, albeit still missing.
Now here’s where it gets weird. After then removing the connection to coil packs 3 & 4 during idle - nothing changes - indicating that those 2 cylinders are still missing, so i’m not sure why it doesn’t cut out at idle anymore (unless it’s because I cleared the codes). Moving on, It was a Sunday, I was an hour from home, and all the local parts stores had closed so I decided to get an AA recovery home.
When the AA guy came, he couldn’t communicate with the PCM to pull any codes for some reason, so we started checking what we could. He took the plug out of cylinder 4 and claimed that it needed a new head gasket because he could see white fluid in the cylinder. I had a look myself, but honestly I couldn’t tell if it was just the white LED reflecting off of unburnt fuel inside the cylinder. I told him to take plug #3 out, but he kind of dismissed what I had to say and started the recovery process.
I’m going to put it on a ramp tomorrow, try and plug some codes, do some tests and have a better look, but I was just wondering if someone had an Idea what this could be?
I know the head-gasket is still a real probability - but I had no loss of coolant, there was no white smoke, and no over-heating.
Anyway, on idle the EML no longer comes on (after disconnecting the battery and allowing the modules to power down), but the warning light now does instead. The first thing I’m going to do is a compression test on all cylinders to see if it is something like the head-gasket, injector seals, or piston rings etc. And then if there is good compression, i’ll move on to checking the coils and plugs.
However, i’m just wondering if someone else has a good idea as to what this could be given the information provided? I am worried it’s something like the turbo, or the timing has skipped and caused a bent valve or something - but it doesn’t seem likely to me considering that the misfire seems to be present on only 2 cylinders, so have you guys got any good guesses? Thanks.
I know these 2.0 TFSI engines are prone to misfires and that the coil packs go on them, so that was what I originally thought was wrong, but the whole thing is kind of baffling really.
I plugged a mate’s scanner in (one of those non-professional phone ones) and it came up with cylinder 4 misfire and a bunch of door module codes. To be honest, I don’t really trust the code reader but I decided to replace the coil pack on cylinder 4 just to see of it was something simple. Originally the car would eventually cut out at idle, but after replacing the coil pack it then started to idle a bit better, albeit still missing.
Now here’s where it gets weird. After then removing the connection to coil packs 3 & 4 during idle - nothing changes - indicating that those 2 cylinders are still missing, so i’m not sure why it doesn’t cut out at idle anymore (unless it’s because I cleared the codes). Moving on, It was a Sunday, I was an hour from home, and all the local parts stores had closed so I decided to get an AA recovery home.
When the AA guy came, he couldn’t communicate with the PCM to pull any codes for some reason, so we started checking what we could. He took the plug out of cylinder 4 and claimed that it needed a new head gasket because he could see white fluid in the cylinder. I had a look myself, but honestly I couldn’t tell if it was just the white LED reflecting off of unburnt fuel inside the cylinder. I told him to take plug #3 out, but he kind of dismissed what I had to say and started the recovery process.
I’m going to put it on a ramp tomorrow, try and plug some codes, do some tests and have a better look, but I was just wondering if someone had an Idea what this could be?
I know the head-gasket is still a real probability - but I had no loss of coolant, there was no white smoke, and no over-heating.
Anyway, on idle the EML no longer comes on (after disconnecting the battery and allowing the modules to power down), but the warning light now does instead. The first thing I’m going to do is a compression test on all cylinders to see if it is something like the head-gasket, injector seals, or piston rings etc. And then if there is good compression, i’ll move on to checking the coils and plugs.
However, i’m just wondering if someone else has a good idea as to what this could be given the information provided? I am worried it’s something like the turbo, or the timing has skipped and caused a bent valve or something - but it doesn’t seem likely to me considering that the misfire seems to be present on only 2 cylinders, so have you guys got any good guesses? Thanks.
I would like to add that an hour before this happened I did money shift into 2nd from 3rd at the redline. I know this can cause a bent valve, but the engine ran fine after that point for at least an hour. Is it possible that I stressed the engine enough at that point which then made it vulnerable to a mechanical failure later - even if nothing failed immediately?
FakeCarGuy said:
Is it possible that I stressed the engine enough at that point which then made it vulnerable to a mechanical failure later - even if nothing failed immediately?
Sadly, yes. Your post suggests it has a severe misfire, possibly one or more cylinders totally dead, and it should be pretty straight forward to confirm whether you have a partial or total misfire and which cylinders are affected. It should also be possible to disciver whether that's due to a gross mechanical failure such as a valve or valve train problem. Do keep in mind that running with a misfire will overheat the cat pretty quickly and without any cooling air flow it can get very hot indeed and could easily be destroyed.GreenV8S said:
Sadly, yes. Your post suggests it has a severe misfire, possibly one or more cylinders totally dead, and it should be pretty straight forward to confirm whether you have a partial or total misfire and which cylinders are affected. It should also be possible to disciver whether that's due to a gross mechanical failure such as a valve or valve train problem. Do keep in mind that running with a misfire will overheat the cat pretty quickly and without any cooling air flow it can get very hot indeed and could easily be destroyed.
To be honest i’m hoping the extent of the damage has only affected the head, because I can find a replacement on ebay for under £200, so won’t break the bank too much. I’ll literally cry if the bottom end is f
ked too hahaha. I’ve only had the car 2 weeks but bought it decatted (was supposed to go to the exhaust shop to get a resonator and sports cat fitted to be honest) so shouldn’t have any problems with the cat. I’m not going to leave it running anyway to be fair.
About to go into work now and give it a proper look.
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