BMW diesel help?

[dombanks]

can anyone make a guess at what might be wrong with my neighbours 08 plate 1series diesel? 

It started to become difficult to start. just slugishly turning over so he replaced the battery. this didnt help and the engine light came on so he had the fault codes read and it was suggested that the fuel pump in the tank was broken so he replaced this which has also not helped. 

Now it will start eventually and idle fine. but if you rev it it and hold it at say 2k rpm after 30s or so the engine lights come on and the revs sort of run away with you and then settle but are lumpy. 

 

I tried using the INPA software i use for the Z but it doesnt list his bmw E number?

[Kit Car Electronics and Essex AO]

Bad earth strap? 

[Blatman]

Leaky or intermittently stuck injectors?

Bad pressure regulator?

Fuel pump replacement hasn't fixed the issue so what is next in that circuit? Injectors then pressure regulator then return to the tank (I assume).

Sticking with the fuelling theme...

It's not getting enough or too much air, so air filter, air flow meter and then maybe O2 sensor in the zorst, if it has one.

Is it fly-by-wire? Throttle pot rears it's head if it is.

And it could well be a bad earth or power feed on any of these items that are controlled or monitored by the ECU.

[DamperMan]

Not sure about an E46...  but the f30 which requires a new battery introduced to the intelligent charge system. Or it results in over/ under charging and can cause voltage issues.  Without plugging it in its hard to guess.  Mechanical stuff... water in the fuel.   Diesels hate air! there’s a load of fuel pipe connectors.   fuel filter. I think is under the car by the gearbox.   

[1960dave]

Firstly have you told the car it has a new battery? When was the fuel filter last changed ( its under plastic trims under the car under the passenger seat) There are a lot of pressure sensors on that N20 engine I hate them. I changed the rocker cover gasket on my sons and it woudn't start ended up with a new engine loom and a new high pressure pump. Its a E87 if its the hatch model. If you need any bits let me know we bought a complete car to fix his that had broke its cam chain but all other parts are great.

[Rob Hunter - Club Secretary]

If it's got stop/start, then the battery will need registering. I use the Carly app and OBD2 reader for my BMW. Not the cheapest but will read all BMW codes and can register the new battery.

 

The runaway symptom sounds like it might be an injector issue which is overfueling and could possibly explain the difficulty starting.

 

Also, make sure to check the engine oil level. If its overfueling and is doing short journeys the dpf could be clogged

[Greenstreak-Andy D]

Erg valve was replaced on my 420 under warranty. Diesel and frequent short trips just don’t mix well. 

[Glen_I]

@dombanks if you and your neighbour were happy to send me reg number via PM, I can look to see if there are any known issues matching that description via the BMW Air/ISTA that is used in the BMW workshop. 

[Glen_I]

I recall EGR wiring being a known issue?? 

 

But as others have pointed out there are so many things that could be at fault, without reading trouble codes you and your neighbour could be running around in circles..

[jim_l]

On 24/02/2021 at 09:54, Glen_I said:

I can look to see if there are any known issues matching that description via the BMW Air/ISTA that is used in the BMW workshop. 

 Do you have insider BMW info Glen?  Slight thread hijack but I have a puzzling issue on my F11 5 series... 

 

I sometimes return to the car and the rear air suspension has gone down, both sides.  The strange symptoms are:

a)  It gives no error, and would let me drive away with no warning

b) It almost never happens if the car is parked level on my drive. but almost always does happen if the car is parked, for example, one wheel on the kerb. 

 

The compressor works fine, raising the car fully in under two minutes, but the timing of the compressor starting is also erratic, sometimes the compressor is running when I sit in having just opened the door. Sometimes the compressor doesn't operate until I turn the ignition on.  

 

Up to now the furthest I have got with diagnostics is to establish that there is no obvious degradation on the air shocks themselves, they look good, it is 2016 with 50k on the clock.  

 

Any thoughts that might save me BM dealer expenses just before I sell the car would be most appreciated! 

 

Jim

 

 

 

[Glen_I]

I don't have any 'insiders' but my job as a Automotive Technical Author compiling and writing repair data/manuals allows me to have access to most mainstream manufacturers websites.

 

I am happy to look to see if there are any known issues to offer assistance but unless I am 100% positive about a particular fault i.e. I have had personal experience within the workshop I am reluctant to suggest components to be replaced as I don't want anything to come back on me with 'you said to change this and it didn't fix the problem', the other issue is being discreet with where the documents come from for obvious reasons.😉

 

 

[jim_l]

38 minutes ago, Glen_I said:

'you said to change this and it didn't fix the problem', the other issue is being discreet with where the documents come from for obvious reasons.😉

 

Thanks Glen,  no comeback on you whatsoever, any input/ideas very welcome and absolutely at my risk, I am not one to look a gift horse in the mouth as they say.  Discretion assured too.    

 

Jim

[Captain Colonial]

@jim_l This might be on interest to you:

 

 

[Glen_I]

Sorry all, I have a slight issue....

 

Just logged into BMW site and the section where the known issues are is all in German, not a problem I thought I will just change language as it has worked in the past....nope still no good so a quick call to the bloke who deals with the license agreements and he said the 'Powers above' won't pay the 50k a year to have it in English despite we use this info,  and as my German isn't all that I could be there for days using Google translate.

 

As a rule info like repair manuals, wiring diagrams and data/tightening torques are never an issue for future reference 😉

[dombanks]

thanks for all the responses, ill pass them on. regarding the battery I asked if it had been registered onto the car and he said it wasn't needed to be but ill double check. 

 

Thats a bummer about being I German. its an issue with the INPA software I have but usually translate sorts it.