Bmw e90 325i n53 injector seals blowing- advice

[skypeller]

Ladies & gentlemen any advice welcome;

A friend of mine has recently bought an e90 3.0 325i auto petrol at auction without seeking advice from me or any other car nut friends.

He took it home after a quick blast and told me he bought it fairly cheap as expected with most auctions, 80k miles etc and sent a video on WhatsApp of it running a little lump and when revved on the video it sounded like a knock, a few days later I got chance to go and see him and have a look at for him. I could tell straight away the engine sounded like it was blowing air through a spark plug thread or injector.
No 5 injector was loose and upon removal, it had no seal !! We found receipts for the car getting work done at a garage 50 miles away, receipt reading “new injector” and a later receipt for “injector seal” .... clearly it’s been suffering with this a little while and the owners off loaded it at auction, can’t say I blame them.

Got my mate to order a seal and explained how to fit it all back and try it, he’s sent me photos today of the injector said the car ran better than ever for about 5 miles and then suddenly pffft fart.... back to same noises and lack of power.... injector back out... seal has vanished ... it was a good fit on the injector he said (he’s not stupid, an industrial engineer) and said you could tell it was a good interference fit with the new seal as he fitted it into the head and then did up the injector securing bracket and pipe.

Has anybody else ever known of any issues with a bmw with direct injection doing this? N52, N53 & n54 etc

If not does anybody have any ideas why it might do it?

[bmwmike]

Never heard of that before

Can't see how the engine is sucking the seal off the injector either. They need a tool to fit them usually, and are a tight fit into the head. Was the coupler element fitted? Wonder if the head has been damaged by the injector hammering about.

[skypeller]

Yes I wonder, it was pushed over the top and felt a good seal, he’s bidding on a new injector on eBay genuine bmw unused but apparently they have to be coded to the car? What a polova!!

[bmwmike]

Yes, the need coding so the DME knows what the flow rate of each injector is and can trim accordingly

[Elliot2000]

Has there buffer been fitted to the injector? It clips on near the end of the injector before the nozzle. Is the clamp being fitted the right way round?

[skypeller]

Hi yes what they call a “decoupler” is fitted, it clips on and sits against the head is that the part you’re referring to?
Yes bracket is correct way around I was hoping that was the answer too

I’ve had a 130i m sport, few 330ci sports myself and they’ve been fantastic! (Touch wood as I own a bmw currently aswell as a westfield for the sunny days)
My dads 320i touring was maintained and driven with respect and the thing popped a valve one morning cruising at 70mph on the way to work .... it went to a European dude who was going to strip it down I think he was convinced it was a coil pack but I explained it had no compression (tested basically everything before giving up)