Can sombody please shed some light on this engine issue

[Smangle]

Hey everybody

So ive had 2 Rczs and still not managed to drive 1 the first engine was rebuilt only to find the vanos vvt on the inlet camshaft had got damaged somehow during the rebuild and the head was scrap it had also damaged the pistons 2 and 4 on start up as the vvt system had the valves stuck wide open.

So we got another 1 it was going cheap local and needed a head gasket and chain replacment after the aux belt had snapped its been put back together turns over by hand smooth with no interference but it just will not run right getting Lean codes for missfires and a miss on cylinder 4 ive attached a diagbox readout from the car if anybody knows what they are looking at and could take a look at the readout id greatly appriciate it i really do not want to be spending much more on it as theyve cost me enough already.

things that have been changed
new bosch maf/map/boost sensors
new bosch front and rear probes
new oil/ filters and plugs
previous owner did say he had removed the vano control servo motor on the back of the engine near the fuel pump as he thought it was the fuel pressure regulator
i have used diagbox to reset the learned adaptions but it appears to have made no diffrence

any help would be very much appriciated.

thanks all

 

[NF7]

I would suggest looking at the High Pressure Fuel Pump, as its failure or issue usually leads to misfire codes on cylinder 4. Also check the status of the ignition coils and spark plugs.

 

[Smangle]

Plugs are brand new denso iridium tip gapped to 0.5 and the coils have been swapped about I'm going to pull the pump and have a look but I've got 2 pumps and it is the same with both of them though 1 is quite old dated to 2012 the other has a 2020 date on it and the paperwork with the car says it's only covered 10000 miles since it was replaced. The car seems to act like it's got a vacuum leak that doesn't clear until it's revved to 3k but I've been all over it and there are no leaks anywhere. Compression test shows 160-165 across the board leakdown test shows less than 3 psi blow by which according to the data I have is well within the 10 psi limit of the pcv system I'm starting to think the vanos timing control motor is out of whack. I have a spare 1 from the other engine but I'm unsure how to reset it once its swapped out as it is a corkscrew style gear on it and I've seen some threads on BMW forums where people have changed the motor solonoid and then wrecked the engine.

 

[Pedro]

1 cylinder misfire might suggest injector dirty or open circuit or fuel injector driver circuit (wiring / PCM) faults can be common on idle but will fade out or disappear as revs increase but the engine needs more fuel to idle correctly (richer Mixture)
Fuel rail sensor?
Knock sensor (misfires)

 

[neilgsxr69]

The cylinder 4 misfire is a common symptom of the HPFP.