2004 BMW 530d won't rev past 2.5k

2004 BMW 530d won't rev past 2.5k

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rs2000t

Original Poster:

3 posts

33 months

Saturday 19th June 2021
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Hi all.
I am desperate for some help.

This is a long story.
I have a 2004 bmw 530d. And basically it will not rev past 2.5k and smokes alot of black
So yesterday me and my brother tried to get to the bottom of it. We plugged it in and it came up with faults galore. Whilst driving yesterday trying to narrow the problems down it cut out and wouldn't restart. So today we tracked it down to fuel pump not coming to life when key is turned and eventually found it kept blowing the 20amp fuse under the passenger pollen filter. To cut the story short we have disconnected the diesel heater on the fuel filter as this was the fuse blowing problem. Is this important or will it be ok disconnected?
And the car started and ticks over lovely.
So we have now put a brand new throttle body maf sensor and all the faults have gone except the maf fault is still coming back. We have tried running the car with the maf disconnected and it still won't rev past 2.5k
And when the maf is reconnected the car seems to tick over nicer. If we disconnect the map sensor at the inlet rear of the car it stops the turbo working and the car revs to just over 4k but is obviously gutless.
Also the car has had new turbo and exhaust manifold recently. We can't find any air leaks etc. And all other faults are clear and not coming back except fault 3FDO air mass flow sensor and we have just replaced it. Any help anyone can give will be much appreciated before I set fire to the thing!

helix402

7,832 posts

181 months

Saturday 19th June 2021
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I’d recheck for air leaks, intercooler and all pipe work.

rs2000t

Original Poster:

3 posts

33 months

Sunday 20th June 2021
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Thanks for replying.

We have checked for boost leaks and all pipes etc and they are are in good condition and we cannot hear any air leaking out.

sortedcossie

539 posts

127 months

Monday 21st June 2021
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I think you'll need to smoke test the pressurised pipework rather than rely on sound.

Touring442

3,096 posts

208 months

Monday 21st June 2021
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Might be an EGR fault (valve jammed open) but my guess is a split in one of the intercooler hoses. The one from the intercooler to the EGR is favourite, normally on the inside bend just before the EGR valve. A tiny split will cause boost loss and clouds of black smoke. BMW will only sell the complete pipe for 8 million pounds but you can buy the rubber section on Ebay for 20-30 quid iirc. Short term it can be bodged with duct tape.

I had this on an E46 330d a year or two ago.

NickXX

1,545 posts

217 months

Wednesday 23rd June 2021
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I had this on a 2002 330d a few years ago. Changed the low pressure fuel pump and it was fine afterwards.

Deano_BMW

428 posts

185 months

Wednesday 23rd June 2021
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did you reset the MAF adaptations after replacing it?

NickXX

1,545 posts

217 months

Wednesday 23rd June 2021
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Not sure - it was a BMW specialist that did it (would have been around 2008).

rs2000t

Original Poster:

3 posts

33 months

Wednesday 23rd June 2021
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Hi all thank you for the responses.
All hoses are fine and cannot find any splits or leaks.
But after further investigation we noticed the exhaust gasses are getting really hot out the exhaust as soon as the map sensor is reconnected and it kinda sounds like a turbine out the end.
I have now replaced the map sensor or what bmw call fuel control its at the back right hand side of the inlet. But the car still runs the same whe it is reconnected.
Also I didn't know you have to reset the maf how do you do this and can it be done with a snap on reader and will I need to do the same with the map sensor?
And another thing I have noticed was as soon as the ignition is turned on I can hear the electric actuator clicking on the side of the turbo.