N53 injector specific misfire persists after a new injector
Discussion
Hi all,
My 2009/59 E92 330i with the N53 engine has a cold start misfire, it's been present since I bought the car on 126,000 miles and still persists today at 150,000 miles. The issue only affects cold engine starts (regardless of ambient temperature) - start up and idle gives you an engine management light and cylinder misfire code, or start up and drive off gives you lumpy misfiring acceleration but no light. After 30 seconds of driving all is well.
I've been trying to hunt the issue down - plugs have been replaced twice in my ownership, coil packs swapped around (it had all six replaced by BMW at 90k miles). The injector part version it is using is the latest version. The persistent fault code is combustion misfire, when swapping coil packs between cylinder 3 and 1 the fault stayed (repeatedly) on cylinder 3. Swapping cylinder 3 injector with cylinder 1 moved the fault, this was reproducible over multiple days and was consistent with cylinder 1 being the culprit.
New injector fitted last week and the problem still persists! I've attached screenshots of fault scanners and dates for the chronology, now it's settled on combustion misfire cylinder 1 and throttle valve potentiometer (cylinder 1 misfire occurred today but the potentiometer code was present after the injector swap). The car no longer stutters when accelerating from a cold start but the start-leave it idling misfire is still present. Before replacing the injector there was a mix of NOx codes and throttle valves. Ignore the exhaust flap codes, these relate to the vacuum flap in the second exhaust which I have disabled (the cold start misfire occurs with or without the flap). I'm posting this as much to ask for advice as to help others as I know there is joy aplenty with N53 engines!
Here's a breakdown of steps so far -
2016-05-31
Codes suggest coil pack or injector Move coil pack from cylinder 3 to 1
2016-06-01
Misfire remains on cylinder 3
Swap cylinder 3 injector on next visit to diagnose if injector is faulty or valve is sticking
2016-06-11
Cylinder 3 injector swapped with cylinder 1
Trigger EML and investigate if fault code moves (faulty injector) or remains (sticking valve)
2016-06-15
Cylinder 1 misfire code
Misfire moved from cylinder 3 after injector swap
Faulty injector?
2016-06-16
Double confirmed cylinder 1
2016-06-21
2016-06-21
150,040 miles
Cylinder 1 injector replaced with identical (latest) P/N
2016-06-25
Throttle valve potentiometer present from cold starts after injector swap. Cold start and misfire detected on cylinder 1.
My 2009/59 E92 330i with the N53 engine has a cold start misfire, it's been present since I bought the car on 126,000 miles and still persists today at 150,000 miles. The issue only affects cold engine starts (regardless of ambient temperature) - start up and idle gives you an engine management light and cylinder misfire code, or start up and drive off gives you lumpy misfiring acceleration but no light. After 30 seconds of driving all is well.
I've been trying to hunt the issue down - plugs have been replaced twice in my ownership, coil packs swapped around (it had all six replaced by BMW at 90k miles). The injector part version it is using is the latest version. The persistent fault code is combustion misfire, when swapping coil packs between cylinder 3 and 1 the fault stayed (repeatedly) on cylinder 3. Swapping cylinder 3 injector with cylinder 1 moved the fault, this was reproducible over multiple days and was consistent with cylinder 1 being the culprit.
New injector fitted last week and the problem still persists! I've attached screenshots of fault scanners and dates for the chronology, now it's settled on combustion misfire cylinder 1 and throttle valve potentiometer (cylinder 1 misfire occurred today but the potentiometer code was present after the injector swap). The car no longer stutters when accelerating from a cold start but the start-leave it idling misfire is still present. Before replacing the injector there was a mix of NOx codes and throttle valves. Ignore the exhaust flap codes, these relate to the vacuum flap in the second exhaust which I have disabled (the cold start misfire occurs with or without the flap). I'm posting this as much to ask for advice as to help others as I know there is joy aplenty with N53 engines!
Here's a breakdown of steps so far -
2016-05-31
Codes suggest coil pack or injector Move coil pack from cylinder 3 to 1
2016-06-01
Misfire remains on cylinder 3
Swap cylinder 3 injector on next visit to diagnose if injector is faulty or valve is sticking
2016-06-11
Cylinder 3 injector swapped with cylinder 1
Trigger EML and investigate if fault code moves (faulty injector) or remains (sticking valve)
2016-06-15
Cylinder 1 misfire code
Misfire moved from cylinder 3 after injector swap
Faulty injector?
2016-06-16
Double confirmed cylinder 1
2016-06-21
2016-06-21
150,040 miles
Cylinder 1 injector replaced with identical (latest) P/N
2016-06-25
Throttle valve potentiometer present from cold starts after injector swap. Cold start and misfire detected on cylinder 1.
Thanks for the replies.
Injectors have been recoded, but the decoupling element was reused. I'll try swapping an injector to bank two. Swapping coil 1/3 no code change and swapping injector 1/3 moved the fault. Presuming coils are OK as they made no difference to code cylinder when changed. Not sure which injector I should move first now, 1/3 have been swapped around so perhaps number 2 with number 5.
Injectors have been recoded, but the decoupling element was reused. I'll try swapping an injector to bank two. Swapping coil 1/3 no code change and swapping injector 1/3 moved the fault. Presuming coils are OK as they made no difference to code cylinder when changed. Not sure which injector I should move first now, 1/3 have been swapped around so perhaps number 2 with number 5.
Not sure tbh
The logic is that as the faulty injector leaks the cylinder runs rich. As the ecu monitors lambda per bank it detects the rich condition and leans off all 3 injectors until the mix is restored. As such 2 of the 3 injectors are now running lean and misfire. This also goes some way to explain why injectors often need to be replaced in banks as the lean injectors apparently get damaged as they are exposed to the overly lean combustion.
My n53 is mis firing I think, or seems very lumpy when holding it around 1200 rpm in neutral. As it switches between stratified and homogenous combustion I can hear the change and feel it through stumbling and misfire. Plan on getting BMW to check it out as have warranty.
Let us know how you get on.
The logic is that as the faulty injector leaks the cylinder runs rich. As the ecu monitors lambda per bank it detects the rich condition and leans off all 3 injectors until the mix is restored. As such 2 of the 3 injectors are now running lean and misfire. This also goes some way to explain why injectors often need to be replaced in banks as the lean injectors apparently get damaged as they are exposed to the overly lean combustion.
My n53 is mis firing I think, or seems very lumpy when holding it around 1200 rpm in neutral. As it switches between stratified and homogenous combustion I can hear the change and feel it through stumbling and misfire. Plan on getting BMW to check it out as have warranty.
Let us know how you get on.
Hi SoupAnxiety I’ve just come across this and some of your other E9x posts. I know you’ve probably moved on from E90 engine woes but I have a quick question re. OBD readers. I’ve just bought a 57 plate E93 325i with 123k miles. Is that your own reader in the pictures? What model is it and would you recommend it? I need to get one so I can get a handle on my engine. Did you use INPA and if so did you have a different OBD adapter? Thanks Michael.
The n53 is a pretty complex engine and needs someone on the ball to understand all the outputs from the code.
Given you have no doubt spent a fair amount already, I would be tempted to email the errors to bimmer profs as they may have some input that helps.
Or, a specialist that is confident with the n53 engine. Tricky to find, mine has just started to msfire since the bad weather last week, so following with interest.
Given you have no doubt spent a fair amount already, I would be tempted to email the errors to bimmer profs as they may have some input that helps.
Or, a specialist that is confident with the n53 engine. Tricky to find, mine has just started to msfire since the bad weather last week, so following with interest.
micdev422 said:
Hi SoupAnxiety I’ve just come across this and some of your other E9x posts. I know you’ve probably moved on from E90 engine woes but I have a quick question re. OBD readers. I’ve just bought a 57 plate E93 325i with 123k miles. Is that your own reader in the pictures? What model is it and would you recommend it? I need to get one so I can get a handle on my engine. Did you use INPA and if so did you have a different OBD adapter? Thanks Michael.
Hi, I see others have confirmed, but it's a Creator C310. I got it for £10 used on eBay, it was handy to check misfire cylinders. It didn't recognise some codes.Since this post I've replaced all my injectors with used index 11 variants collected on eBay. Installed in February 2017 and no issues since, cold starts fine etc for over two years. I've also installed a NOXEM sensor which has improved MPG (30ish round town, 45 on a steady 70 MPH motorway run - seriously!). Also means I have zero fault codes on a 183k mile 10 year old E92 N53 330i.
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