Birchall
Dick Chown Award 2016
Hi,
I had a small but annoying problem with the FSI for the last few weeks.
Almost every morning (and on cold mornings EVERY morning) at almost exactly the same spot and within 2 minutes from leaving home each time), the car would suddenly go into limp mode and the warning lights seemed to light up like a Christmas tree.
Switching off and on again cancelled the Limp mode and so it was no big deal. The EPC light stayed on though unless I switched off and restarted a few times.
A check on VCDS seemed to be complaining about an air leak, and since it ran beautifully well apart from this and never did it after 2 minutes of running, I was not so worried.
I checked for an air leak and no sign!
I had my local mechanic look at it and he could not find a leak either.
So after a couple more weeks of the daily ritual, I decided enough is enough and so I went down, took the bonnet off and I was determined to find out what was causing it.
I did my usual "clutching at straws" and even resorted to jiggling every pipe I could see. But then I jiggled the oil filler cap (the one on the rocker cover) and it was not as tight as it should be the cap itself was tight and well sealed, but the bit the cap twists onto (it is the bit that twists into the rocker cover) was loose.
"No" I thought, how could that be related to an air leak it is not part of the intake system at all. But I had a spare rubber (flat) seal and so I added that to the one that was on already and that made it nice and sealed and no longer loose).
I carried on looking because I was sure that it would not be as easy a fix as that, and gave up, there was no leak and so nothing else for me to do.
Then after coming back in to the warm, my brain must have warmed up a bit too, because that really could be the cause because there is a pipe that exits that exact piece and that is effectively the breather pipe that connects to the inlet side of the engine (these are pretty much a sealed crankcase system).
So the next morning I was thinking, "this is too good to be true, surely it will still go into limp mode".
I tried not to do anything different (because if I was ever to run the car for a minute or two without driving off it sometimes didn't go into limp mode.) and WOW Noi Limp Mode!!!!!
I still didn't think it was fixed because I didn't think I could be so lucky and so for the next week I deliberately didn't do anything different (and it was starting to get very cold of a morning) and amazingly it has fixed the problem.
The car ran GREAT anyway before I fixed this and it is still running great now and with no limp mode and the error was cleared and it has not returned.
This might not help many FSI owners, but it MIGHT! especially if you have done anything in that area and more so if you have ever untwisted that bit.
One word of warning, it normally becomes loose because someone has tried to get that bit off, not realising how it twists off and the metal arm that locates it gets bent and causes a loose seal. DO NOT just try and straighten that arm (which was my first action) the metal locating plate is very thin and yes it bends back, but not all of the way, and worse still mine snapped while I was forcing it. If you try bending that bar and then put it back on, if that arm snaps, those two pieces of metal are then going to drop into your rocker and into the engine internals. The only real solution is to buy a good used or new "sandwich bit" that twists onto the rocker and has the opening at the top where you twist on the oil filler.
Even doing what I did and fitting an additional seal is only a temporary measure, that solution also exerts a bit more pressure on the locating bar.
But if you are suffering from limp mode most mornings on your FSI this is worth checking.
As for why it only does it within the first minute or so, I believe that this is because on the FSI it starts off with a different fuel trim for the first minute or so and the extra air, at a time when it is putting in a bit of extra fuel anyway meant that the imbalance was more noticeable.
One closing comment, as a confirmed TDI fan, all I can say is when it comes to driveability and outright performance (actual or perceived) the FSI really "stirs the juices" and taking the revs up to 5000 / 5500 when pulling onto the motorway is a joy!!!
Have fun
Steve B
I had a small but annoying problem with the FSI for the last few weeks.
Almost every morning (and on cold mornings EVERY morning) at almost exactly the same spot and within 2 minutes from leaving home each time), the car would suddenly go into limp mode and the warning lights seemed to light up like a Christmas tree.
Switching off and on again cancelled the Limp mode and so it was no big deal. The EPC light stayed on though unless I switched off and restarted a few times.
A check on VCDS seemed to be complaining about an air leak, and since it ran beautifully well apart from this and never did it after 2 minutes of running, I was not so worried.
I checked for an air leak and no sign!
I had my local mechanic look at it and he could not find a leak either.
So after a couple more weeks of the daily ritual, I decided enough is enough and so I went down, took the bonnet off and I was determined to find out what was causing it.
I did my usual "clutching at straws" and even resorted to jiggling every pipe I could see. But then I jiggled the oil filler cap (the one on the rocker cover) and it was not as tight as it should be the cap itself was tight and well sealed, but the bit the cap twists onto (it is the bit that twists into the rocker cover) was loose.
"No" I thought, how could that be related to an air leak it is not part of the intake system at all. But I had a spare rubber (flat) seal and so I added that to the one that was on already and that made it nice and sealed and no longer loose).
I carried on looking because I was sure that it would not be as easy a fix as that, and gave up, there was no leak and so nothing else for me to do.
Then after coming back in to the warm, my brain must have warmed up a bit too, because that really could be the cause because there is a pipe that exits that exact piece and that is effectively the breather pipe that connects to the inlet side of the engine (these are pretty much a sealed crankcase system).
So the next morning I was thinking, "this is too good to be true, surely it will still go into limp mode".
I tried not to do anything different (because if I was ever to run the car for a minute or two without driving off it sometimes didn't go into limp mode.) and WOW Noi Limp Mode!!!!!
I still didn't think it was fixed because I didn't think I could be so lucky and so for the next week I deliberately didn't do anything different (and it was starting to get very cold of a morning) and amazingly it has fixed the problem.
The car ran GREAT anyway before I fixed this and it is still running great now and with no limp mode and the error was cleared and it has not returned.
This might not help many FSI owners, but it MIGHT! especially if you have done anything in that area and more so if you have ever untwisted that bit.
One word of warning, it normally becomes loose because someone has tried to get that bit off, not realising how it twists off and the metal arm that locates it gets bent and causes a loose seal. DO NOT just try and straighten that arm (which was my first action) the metal locating plate is very thin and yes it bends back, but not all of the way, and worse still mine snapped while I was forcing it. If you try bending that bar and then put it back on, if that arm snaps, those two pieces of metal are then going to drop into your rocker and into the engine internals. The only real solution is to buy a good used or new "sandwich bit" that twists onto the rocker and has the opening at the top where you twist on the oil filler.
Even doing what I did and fitting an additional seal is only a temporary measure, that solution also exerts a bit more pressure on the locating bar.
But if you are suffering from limp mode most mornings on your FSI this is worth checking.
As for why it only does it within the first minute or so, I believe that this is because on the FSI it starts off with a different fuel trim for the first minute or so and the extra air, at a time when it is putting in a bit of extra fuel anyway meant that the imbalance was more noticeable.
One closing comment, as a confirmed TDI fan, all I can say is when it comes to driveability and outright performance (actual or perceived) the FSI really "stirs the juices" and taking the revs up to 5000 / 5500 when pulling onto the motorway is a joy!!!
Have fun
Steve B
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