BMW Diesel System Cleaning?

GR63 · 11 Aug 2023 at 16:56

2016 1 Series B47 Engine.

Had some hesitation with car when accelerating and a one off "limp mode" in the auto box. I drive VERY sedately and economically. Basically I drive it every 2 weeks to visit my old mum (70m there, 70m back up the motorway mostly). I've used 5 bottles of Redex Diesel system cleaner in 18m since I have had the car (just cos I thought it would help keep things clean).

Anyway I got Torque and OBD adapter out and have two codes P0401 Powertrain "EGR Flow Insufficient" and P22AE Powertrain something O2 Sensor related. I removed O2 sensor and cleaned with brake cleaner and put back. No change. Clear codes and they just come back. The Engine warning light came on but now goes out. So I thought given how my driving is very "granddad" I took it out and thrashed it a bit (manual mode rev to 5k) - no black smoke though - it revs fine and pulls fine. So I thought reset the codes. And they instantly reappear.

Next is remove EGR valve and clean but I am not expecting that to fix (and have to wait for long reach Torx screwdriver to be able to do next week). I am wondering if removal of the Intake Manifold (big black plastic thing on BMW B47 engine) will reveal gunking up requiring caustic soda bath or similar.

But happy to get advice on other things I can try. Should I still be driving it?

Tempted also to add Dipetane to my diesel to keep it clean longer term as I'm not a heavy mileage user so it may need that? Thoughts?

gc123 · 11 Aug 2023 at 20:36

when ive had this on other cars, zaphira/honda/etc ive always gone and got a can of mr muscle oven cleaner, or in the old days poundland special.
give it a rough clean the completly soak it in it so it all foams up and leave it for 30 min to a hour.
then clean with either a hosepipe ot better a pressure washer, depending on mileage expect to become very black

in the old garage days we used to have a machine we connected up to run chemical through the system so the car effectivly ran on a bottle of additive and not its own fuel, always sorted emission problems out and many people said how good it was i believe it was similar to running on forte addative/flush.
again knowing what mileage you have on the car would help a little.

Begbie · 11 Aug 2023 at 20:48

I'd imagine 300 miles every month is enough to not worry about additives into the fuel system?

Rroff · 12 Aug 2023 at 10:35

O2 sensor might be bad as in not fixable by cleaning or not actually the problem but detecting the problem caused by something else like bad MAF data or sticking EGR valve, etc.

Dis86 · 12 Aug 2023 at 11:19

Money would be on clogged EGR valve.

Gaygle · 12 Aug 2023 at 11:48

I think the EGR is going to need a clean at minimum. Also, is your car affected by the EGR cooler safety recall?

And again, it's probably cheaper to drive the car "properly" and not so overly fuel efficient, than to start paying for numerous products to fix it when it gets gunked up because the exhaust doesn't reach a high enough temperature.

MrRockliffe · 13 Aug 2023 at 12:01

Could be the EGR but I’ve seen timing chain issues setting off EGR error codes too.

GR63 · 13 Aug 2023 at 12:43

gc123 said:
when ive had this on other cars, zaphira/honda/etc ive always gone and got a can of mr muscle oven cleaner, or in the old days poundland special.
give it a rough clean the completly soak it in it so it all foams up and leave it for 30 min to a hour.
then clean with either a hosepipe ot better a pressure washer, depending on mileage expect to become very black

in the old garage days we used to have a machine we connected up to run chemical through the system so the car effectivly ran on a bottle of additive and not its own fuel, always sorted emission problems out and many people said how good it was i believe it was similar to running on forte addative/flush.
again knowing what mileage you have on the car would help a little.

About 42k I think

Begbie said:
I'd imagine 300 miles every month is enough to not worry about additives into the fuel system?

Yeah I thought so but doesnt hurt does it?

Rroff said:
O2 sensor might be bad as in not fixable by cleaning or not actually the problem but detecting the problem caused by something else like bad MAF data or sticking EGR valve, etc.

I thought same but cleaned to hopefully take out of equation. Will find out when EGR cleaned hopefully

Dis86 said:
Money would be on clogged EGR valve.

Mine too, well actually I think Intake also likely but should have tools to get EGR off this week

Gaygle said:
I think the EGR is going to need a clean at minimum. Also, is your car affected by the EGR cooler safety recall?

And again, it's probably cheaper to drive the car "properly" and not so overly fuel efficient, than to start paying for numerous products to fix it when it gets gunked up because the exhaust doesn't reach a high enough temperature.

Yes, no sign of codes until after it went for recall and BMW dealer said "you have a code" and presumably expected me to

I'd have thought a 65 mile run at 65 mph would warm it enough?

gc123 · 13 Aug 2023 at 16:10

does seem pretty low for egr problems but i suppose it may be lots of short journeys. as regards adding additive i still chuck a bottle in every service .

GR63 · 28 Aug 2023 at 18:42

I'm awful on the names of the tools but can anyone tell me what it looks like this guy used (long reach but also with bendy head at end). I'm sure once EGR is clean the intake WILL need same. Son suggested a stocking-like filter on vacc cleaner when sucking the crap out of the engine so as not to trash Mrs precious Dyson ;-)

GR63 · 15 Nov 2023 at 14:44

MrRockliffe said:
Could be the EGR but I’ve seen timing chain issues setting off EGR error codes too.

So I took to a specialist who basically just wanted to change everything they could at my expense AND charge me over retail prices for parts. So I took it home

I then took EGR out myself and it had got stuck. I freed it up, cleaned it properly and using software retracted it before refitting. And cleared code and not returned. Have to do similar with Lambda sensor (or replace) but given how the specialist was not interested in listening to me suggest what problem was, I think I'd rather do myself in future.

Never done anything on car before but YouTube is a good teacher

MrRockliffe · 15 Nov 2023 at 15:03

GR63 said:
So I took to a specialist who basically just wanted to change everything they could at my expense AND charge me over retail prices for parts. So I took it home

I then took EGR out myself and it had got stuck. I freed it up, cleaned it properly and using software retracted it before refitting. And cleared code and not returned. Have to do similar with Lambda sensor (or replace) but given how the specialist was not interested in listening to me suggest what problem was, I think I'd rather do myself in future.

Never done anything on car before but YouTube is a good teacher

Yeah sounds about right.

Family friend has just had everything done on the 120i engine in an E88. They've finally sorted it but had about 2k of work done on it, including timing chain, NOx sensor, coil packs and other stuff.

gc123 · 16 Nov 2023 at 12:45

MrRockliffe said:
Yeah sounds about right.

Family friend has just had everything done on the 120i engine in an E88. They've finally sorted it but had about 2k of work done on it, including timing chain, NOx sensor, coil packs and other stuff.

problem is some of these specialists just want to keep changing parts without proper diagnosis. i suppose a product of todays fast throwaway society.
in the old days we were taught to find the problem before committing customers funds.