[timwicks]

Hi,

I'm new to the forum but hoping one of you may be able to help with my issues!!!

I have a BMW 320i (N43), couple of months ago it started with a slighty lumpy cold start and hesitation for about 10-15 minutes until it had warmed up. Also at this stage it sounded very ticky!!!

I had the timing chain kit replaced (preventative not because of a fault), coil packs, spark plugs and a full major service as well....this was around a month ago.

A few days ago after driving for about 45 minutes the car seemed to lose it power, it would still drive but seemed very flat and very lumpy. Also it seemed to bunny hop down the road if the revs fell below 1500

I had the AA out to the car who scanned the ECU (never had any lights on dash) and the code came up for the Mass Air Flow meter and the NOX sensor which was sulphurised.

Any way, managed to get the car into a BMW dealer who diagnosed the car with the same faults as the AA and changed both Mass Air Flow and NOX sensor, put the car into a "regen mode" and took it for a 30 minute blast down the motorway. As soon as I got the car home it again was lumpy on tickover, sounded very rough and was just not a very happy little motor!!!

The BMW dealer has said that all injectors had tested OK and there is nothing else showing as a fault but obviously there has to be something.

Any help anyone can offer will be much appreciated.

Many thanks


Tim

[Dormermike]

Do these have the same HPFP as the n53?

Was it running OK before the timing chain work?

[timwicks]

Hi Dormermike,

Thanks for your reply, I'm not sure about the HPFP i'll check now on realoem, it was lumpy on idle and hesitating until it got up to temperature before the timing chain was changed

[timwicks]

Looking at a parts web site it would appear that they do use the same pump

[jwilalex]

When you took it for the blast down the motorway did you have more than half a tank of fuel in the car? As part of a different fault rectified under warranty on my motor the dealer also picked up it was needing a de-sulphurising run which they initiated and did before handing back. Anyway I was informed by the tech bod that the following had to be met to instigate and successfully complete a run:

1. More than half a tank of fuel (for duration of run).
2. Must be 70 mph or over for 30 min to kick in and complete fully.

I'd also whip out the camshaft correlation and exhaust sensors and give them a clean. They are identical and sit fairly close to each other at the front of engine. If they're gummed up with sludge it may affect your running.

[timwicks]

Evening Jwilalex, I had 3/4 tank of shell petrol (not V-Power!!) and sat between 70-80mph for 35 minutes. These sensors you describe, are they the VANOS solenoids?

[timwicks]

Also, I considered having this TerraClean engine cleaning done......any thoughts?

[Dormermike]

Bunny hop makes me think air leak.

Possibly a few things going on here.

No codes?

How many miles?

How long have the symptoms been going on for and did they suddenly start or was it after having some work done..

[timwicks]

The symptoms began about 8 weeks ago. I had the timing chain kit replaced including tensioner etc and it was still the same.

The symptoms got worse last week after a normal drive nothing spirited!!!

There are no codes left in the car and the mileage is 115k.

I am leaning towards a leaking injector

[Dormermike]

Could be

When my injectors were leaking the plugs came out wet with petrol... worth a look after its been standing for a while

[timwicks]

I'll definitely do that....in fact I've got a really good indy who has said he's got some good injectors. He's going to change them out one by one on Wednesday and see if it makes a difference......I won't be holding my breath though lol

[jwilalex]

While he's at it have him whip out the two sensors (vansos, camshaft intake/exhaust correlation - not sure of correct terminology but there are two almost beside each other at front).

I'm contemplating a terra clean on mine to see if it will boost MPG figures a little and just to give the system a thorough clean through. £130 is a rough price and takes about an hour.

[Dormermike]

Take the plugs out and have a look after its been stood over night. If the plugs are wet the injector is leaking.

[timwicks]

There is a mobile Terraclean guy near me, he asks for £100 for a fuel system clean or a "special offer" price of £160 for a fuel system and decoking clean. Not sure whether its gonna throw up a lot of issues that I really don't want to deal with right now lol!!!

[timwicks]

Evening All,

Sorry I haven't updated, been trying to get this car sorted......ok heres the update, I've changed all injectors, VANOS solenoids and NOX sensor and still the car is running lumpy at cold. I really have no more ideas on where to go from here......

Any more ideas???????


Thanks in advance

Tim

[Dormermike]

Running lumpy but no codes?

[Rustymage]

Coil pack?

Still no codes?

[timwicks]

Still no codes.....still running lumpy from cold start, mpg has increased

I'm confused, even thinking about having one of these terracleans done with a decoke aswell!!!!

[davealfa11]

anyone done a compression check ....furthermore on a new maf fitted did they erase the learnt values from old maf sensor?

[timwicks]

No compression check been done because after 10 mins of running it runs ok. I fitted the maf myself so nothing been erased!!! Spoke to BMW and asked if it needed programming in and they said no......

[Dormermike]

Forget the tarraclean it's snake oil

How lumpy? Missing a cylinder lumpy? Would have a code for that... So how are you reading the codes..?

Can you post a screenshot of a rough running screen on I PA or ISTA ?

[Dormermike]

Can you post a video of it running lumpy?

We can help you... Just think we need to get back to basics

Would say injector ordinarily but you've replaced all with new right?