320d N47

AlexGSI2000 · 12-20-2021, 09:48 AM

Afternoon,

I'm at a bit of a loss as to why I'm getting incredibly smoky cold starts now the weather has become colder - was wondering if anyone has had a similar issue to mine?
(TLDR; replaced glow plugs and module, but fault codes come back after clearing)

The car always did have a slightly smoky start, but recently it has become far worse.
I did suspect the glow-plugs were at fault around a year ago - this was confirmed after scanning the car.
I replaced these with new Beru parts, but the codes came back after clearing.
At the time I just learned to live with it, as the smoke would clear after around a minute of driving.
At the moment the smoke only clears after a few minutes of driving and is quite embarrassing

I'm beginning to wonder if the glow plug control module / relay may have been defective when new? or if there is another element to the system I may have missed (maybe a fuse or a relay somewhere?)

I thought the cable from the relay to the alternator may have been the issue, but have swapped over with a known good part - this made no difference.

Would be great to get to the bottom of this one if anyone can offer any pointers?

I have owned the car around three years, originally purchased the car with a dead engine (bottom end seized), I fitted a used engine and fitted a new timing chain at the same time, as well as removing the swirl flaps, EGR and DPF.
Have covered around 50,000 miles in this time and carried out regular oil changes every 6,000 miles.

The crankcase blow-by and breather seem to be fine after comparing with a friends N47 engine.

Many thanks!

nomiS330d · 12-22-2021, 11:12 PM

My 330d has always been the same. I’ve never had a glow plug fault code so I suspect they’re just coked up on the heating tips. It always starts but takes twice as much cranking when it’s very cold then belches smoke for a few seconds. I guess it’s because it’s pumping loads of diesel in which when it eventually starts turns to smoke.
Every winter I say to myself I’m going to change them when the weather warms up but then the starting issue goes away so I forget about it lol.

12-20-2021, 09:48 AM	#1
AlexGSI2000 Registered 0 Rep 2 Posts Drives: e39 M5, e90 320d Join Date: Jun 2020 Location: Liverpool - UK iTrader: (0)	320d N47 - Very Smoky Cold Start Afternoon, I'm at a bit of a loss as to why I'm getting incredibly smoky cold starts now the weather has become colder - was wondering if anyone has had a similar issue to mine? (TLDR; replaced glow plugs and module, but fault codes come back after clearing) The car always did have a slightly smoky start, but recently it has become far worse. I did suspect the glow-plugs were at fault around a year ago - this was confirmed after scanning the car. I replaced these with new Beru parts, but the codes came back after clearing. At the time I just learned to live with it, as the smoke would clear after around a minute of driving. At the moment the smoke only clears after a few minutes of driving and is quite embarrassing I'm beginning to wonder if the glow plug control module / relay may have been defective when new? or if there is another element to the system I may have missed (maybe a fuse or a relay somewhere?) I thought the cable from the relay to the alternator may have been the issue, but have swapped over with a known good part - this made no difference. Would be great to get to the bottom of this one if anyone can offer any pointers? I have owned the car around three years, originally purchased the car with a dead engine (bottom end seized), I fitted a used engine and fitted a new timing chain at the same time, as well as removing the swirl flaps, EGR and DPF. Have covered around 50,000 miles in this time and carried out regular oil changes every 6,000 miles. The crankcase blow-by and breather seem to be fine after comparing with a friends N47 engine. Many thanks!
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12-22-2021, 11:12 PM	#2
nomiS330d Lieutenant 75 Rep 541 Posts Drives: E92 330d Join Date: Jul 2017 Location: Doncaster iTrader: (0)	My 330d has always been the same. I’ve never had a glow plug fault code so I suspect they’re just coked up on the heating tips. It always starts but takes twice as much cranking when it’s very cold then belches smoke for a few seconds. I guess it’s because it’s pumping loads of diesel in which when it eventually starts turns to smoke. Every winter I say to myself I’m going to change them when the weather warms up but then the starting issue goes away so I forget about it lol.
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