Discussion
I know there's dozens of N53 misfire threads out there but struggling to find any with the exact same symptoms and I'm trying to make sure I've covered everything before I go buying expensive parts like injectors.
The car is a 2009 325i with the N53 petrol engine on 142k miles.
It starts first time but splutters and misfires, and skmetimes stalls when idling. This usually clears up after a couple of minutes and, if the engine management light does come on it goes off again after I restart it.
There is also, often, a cloud of blue (oily) smoke when starting off but this clears.
When I have checked the codes (with a basic code reader, nothing fancy) it has said misfire on one of cylinders 4, 5 or 6, or occasionally catalyst not functioning. I think it was P0430 but I can check next time.
Once it's been running for a while it idles smoothly and drives fine, though sometimes judders a bit under heavy load at low revs.
I know injectors are a problem on the N53 but I don't know if that would give blue oil smoke?
I understand the CCV membrane could also be a culprit but there doesn't seem to be a strong vacuum under the oil cap and oil consumption is pretty reasonable.
There's an electric fan blowing strong from start up, which makes me wonder if the temperature sensor is possibly playing up?
The last thing is, I seem to have an oil leak at the top of the engine, perhaps from around the filter housing, and I wonder if this could be messing things up?
Thanks in advance for any help.
The car is a 2009 325i with the N53 petrol engine on 142k miles.
It starts first time but splutters and misfires, and skmetimes stalls when idling. This usually clears up after a couple of minutes and, if the engine management light does come on it goes off again after I restart it.
There is also, often, a cloud of blue (oily) smoke when starting off but this clears.
When I have checked the codes (with a basic code reader, nothing fancy) it has said misfire on one of cylinders 4, 5 or 6, or occasionally catalyst not functioning. I think it was P0430 but I can check next time.
Once it's been running for a while it idles smoothly and drives fine, though sometimes judders a bit under heavy load at low revs.
I know injectors are a problem on the N53 but I don't know if that would give blue oil smoke?
I understand the CCV membrane could also be a culprit but there doesn't seem to be a strong vacuum under the oil cap and oil consumption is pretty reasonable.
There's an electric fan blowing strong from start up, which makes me wonder if the temperature sensor is possibly playing up?
The last thing is, I seem to have an oil leak at the top of the engine, perhaps from around the filter housing, and I wonder if this could be messing things up?
Thanks in advance for any help.
When you experience a misfire, the first thing to do is find out which cylinder it occurs on.
Once you know which pot has the problem, swap the coilpack and sparkplug from the next cylinder onto the one that has the problem and try it again.
If the misfire moves the the other cylinder that you just swapped coil and plug to, then you know its the coil or the plug.
If the misfire stays on the same cylindr after you swap the coil and the plug, then you need to look at the injector (hint - pull the spark plug and smell it - you either will smell fuel or you wont)
If the misfire stays in the same place after you swap ignition compentns AND the plug smells like fuel then perfomrm compression tests and leakdown tets on that cylinder determine if its mechanical.
You can buy cheap OBD code readers of ebay between 15quid to about 40.
You can get the Carly app on your phone for dealer level diagnostics in your hand.
now the evenings are a bit lighter you can investigate tonight and order parts online, collect and fit tomorrow and problem solved.
Once you know which pot has the problem, swap the coilpack and sparkplug from the next cylinder onto the one that has the problem and try it again.
If the misfire moves the the other cylinder that you just swapped coil and plug to, then you know its the coil or the plug.
If the misfire stays on the same cylindr after you swap the coil and the plug, then you need to look at the injector (hint - pull the spark plug and smell it - you either will smell fuel or you wont)
If the misfire stays in the same place after you swap ignition compentns AND the plug smells like fuel then perfomrm compression tests and leakdown tets on that cylinder determine if its mechanical.
You can buy cheap OBD code readers of ebay between 15quid to about 40.
You can get the Carly app on your phone for dealer level diagnostics in your hand.
now the evenings are a bit lighter you can investigate tonight and order parts online, collect and fit tomorrow and problem solved.
I don't have a full history of the car so I don't know how well it has been maintained. No obvious signs of bodging nor any of boundless love and care, but it generally runs well and doesn't use much oil.
The guy I bought it from had just changed the cam cover gasket and said everything looked very sound inside. As I suppose he would! But that was 15k miles and a year ago.
I'm not sure about injector index. Apart from oil changes I haven't done anything to the car as it hasn't needed it. If it's 6 new injectors at £200 a go it probably won't be worth repairing!
I change the oil every 5k and have top it up with about half a litre every couple of thousand miles.
I'm away at the moment but should have a chance to play around with it next week, so trying to get an idea where to look now.
The guy I bought it from had just changed the cam cover gasket and said everything looked very sound inside. As I suppose he would! But that was 15k miles and a year ago.
I'm not sure about injector index. Apart from oil changes I haven't done anything to the car as it hasn't needed it. If it's 6 new injectors at £200 a go it probably won't be worth repairing!
I change the oil every 5k and have top it up with about half a litre every couple of thousand miles.
I'm away at the moment but should have a chance to play around with it next week, so trying to get an idea where to look now.
Id probably do the following in this situation:
1. Put 6 x new coil packs/sparks on it, itll cost you £160 from ECP on a discount day. That will remove electrical/spark considerations.
2. Reset the codes
3. If the codes come back, pull the plugs after leaving it overnight. I imagine either 4/5/6 will stink. If they are really buggered, the fuel will wash the cylinder liners of oil and when you start the car, you'll be burning oil and fuel, hence the puff of blue smoke.
4. Buy 3 x Index 11's off ebay and fit them to the 4/5/6 bank. Code them in INPA.
5. Reset the codes
6. Give it a few days and report back.
Hope that helps.
1. Put 6 x new coil packs/sparks on it, itll cost you £160 from ECP on a discount day. That will remove electrical/spark considerations.
2. Reset the codes
3. If the codes come back, pull the plugs after leaving it overnight. I imagine either 4/5/6 will stink. If they are really buggered, the fuel will wash the cylinder liners of oil and when you start the car, you'll be burning oil and fuel, hence the puff of blue smoke.
4. Buy 3 x Index 11's off ebay and fit them to the 4/5/6 bank. Code them in INPA.
5. Reset the codes
6. Give it a few days and report back.
Hope that helps.
Seems like sound advice. Though being a miser I'll probably mess around with the coils and plugs one by one before buying 6. With the car running as smoothly as it does when it's warmed up I suspect it's only one playing up.
Intrigued by the valve stem seals as I hadn't considered that.
Will definitely report back.
Thanks
Intrigued by the valve stem seals as I hadn't considered that.
Will definitely report back.
Thanks
Sorry it just sank in what you meant about washing oil off the cylinder liners. It seems like a bit too much smoke for that, although that's only based on my fairly amateur guess. Presumably the valve stem seal would stop be dripping away and allow a lot more settle in the cylinder over night? There's barely any blue smoke after 4 or 5 hours parked outside work during the day.
JuanCarlosFandango said:
An update. Finally had time to have a poke around and despite what I said before the ccv valve is definitely playing up. High pitched whine and vacuum under the oil cap. I like the idea of the aluminium one from one but ordering it from Russia is a bit of a pain. Anyone done this?
I have done it on mine N53 engine couple years ago, ordered membrane and aluminium cap from Russia. You need to carefully remove top cap, change membrane and using black high temperature silicone adhesive fit aluminium cap.Driven around 20k miles no problem at all.
Just a quick update in case it helps someone else.
I replaced the membrane with the kit from Vanos BMW who were great to deal with. Took about 3 weeks to arrive. This improved the idle but didn't solve the cold start misfire.
A new set of spark plugs and a good clean up of all the oil that had leaked and been spilled vastly improved things but there was still a judder under load.
Some Redex fuel system cleaner really has made a difference and the car hasn't missed a beat this week. Warmer weather might be helping too, but after a lot of reading up on the subject I suspect the problem was mostly the injectors coking up rather than being actually being finished, and because of how the direct injection works these engines are particularly sensitive to the spray pattern being disrupted. Mine are index 4, I don't know when the different index numbers were released but the previous owner didn't know if they were changed so they have obviously been in a good while.
Anybody know the release dates of injectors?
This and reading the various threads on N53 injector problems got me thinking that a lot of people probably panic, and garages not wanting to spend weeks chasing a misfire around probably go for the nuclear option and change everything.
Or am I talking complete rubbish?
I replaced the membrane with the kit from Vanos BMW who were great to deal with. Took about 3 weeks to arrive. This improved the idle but didn't solve the cold start misfire.
A new set of spark plugs and a good clean up of all the oil that had leaked and been spilled vastly improved things but there was still a judder under load.
Some Redex fuel system cleaner really has made a difference and the car hasn't missed a beat this week. Warmer weather might be helping too, but after a lot of reading up on the subject I suspect the problem was mostly the injectors coking up rather than being actually being finished, and because of how the direct injection works these engines are particularly sensitive to the spray pattern being disrupted. Mine are index 4, I don't know when the different index numbers were released but the previous owner didn't know if they were changed so they have obviously been in a good while.
Anybody know the release dates of injectors?
This and reading the various threads on N53 injector problems got me thinking that a lot of people probably panic, and garages not wanting to spend weeks chasing a misfire around probably go for the nuclear option and change everything.
Or am I talking complete rubbish?
Do you need the car for daily use? I'd be tempted to strip the injectors out and send them for ultrasonic cleaning.
I agree that a lot of garages will want to throw a set of items on the car - the more time they have the car in their care (potentially 6x replacement cycles), the less chance they have of using the same space for more profitable jobs.
I agree that a lot of garages will want to throw a set of items on the car - the more time they have the car in their care (potentially 6x replacement cycles), the less chance they have of using the same space for more profitable jobs.
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