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Running Issues 528i

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Hi Guys,

Just wanted to see if anyone else out there has encountered similar problems with their L-Jet 528i engines.

The car turns over three or four times first thing in the morning before catching, but it always starts (I've tried turning the key to initially prime the pump and then all the way and it makes no difference). IF I try to start and it doesn't quite catch and then I turn the key again, it starts IMMEDIATELY. 

Once started it smells quite rich and after 5-8 seconds it relaxes into quite a lumpy idle - If I then drive away, for the 2-3 mins or so of driving its pretty sluggish and really lacks power - a real flat spot (at this point if I kick the car down it comes to life and runs fine) It may run a wee bit more lumpy until it reaches running temp and the car then runs perfectly (still rich and an idle of 750-800 in D and 900-950ish in N, which I think is a bit too high).

For the rest of the day the car functions perfectly (it still might not start immediately on the first turn of the key, but its much faster, and most times it does). Its still ever so slightly lumpy but its barely perceptible and I guess that a 36 yo M30 engine running 98 RON will always run a bit rich and a bit lumpy (Its only got 75k on it so its not a high mileage engine)??? 

Given the rich running, initial startup issues, lack of power etc I would've thought leaking injectors/cold start injector.........(I've replaced the FPR with new genuine)

I've had all the vaccum pipes checks and replaced and I don't think this is the issue here.

The in-tank pump has been replaced with Genuine BMW and the external one is making fluctuating buzzing noises (and will be replaced next week, along with the Dizzy Cap & Rotor)

I'd love to change the ECU, DME Relay, AFM, but these are prohibitively expensive so want to leave these til last.

Any further ideas - DME Temp sensor? 

I know the above is all over the place..........fairly similar to my head-space regarding this.........

Any similar stories or woe out there??? How did you fix???





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Before you bin the old one try opening up the black cover and shifting the track /wiping surface a mm or so. This gives a fresh surface for the wiper arm and can restore an old afm. 


With spares getting rarer it’s always handy to have a spare in stock. 

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Hi Al,


Do not bin the old AFM as they are a "core" item from the main stealers.  This means that they charge a deposit (core) on a new item which they hold onto until you return an old one.


So your old AFM has a value for somebody looking to purchase an AFM to hold as a spare as they can return an addition duff AFM so as to recover the "core" and hold a spare.


Just been around this AFM buoy with the Diamantschwartz eta  :rolleyes:






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Thanks guys, was defo holding onto it and was going to get it refurbed (or use it to lower the price of new, which I think I'll do in the next few months) - I did previously take it apart and delicately tried to alter the track (and moved the cog two to three spaces to lean out the mixture and it helped a wee bit). The replacement AFM has totally transformed the car - its up on power all through the range and idles as steady as a rock now.......I'm bloody over the moon as it was the ECU next and then god knows where (needle in haystack, I feared). 

I'd honestly forgotten how smooth an M30 could be when running really well. Its taken 9 months and approx $15k (GBP7-8000) but its now there (whispered, in case the fecker hears me!).

Really want an Eta too now (My first E28 was an '85 Saturn Blau 525e in perfect condition and still my favourite E28)

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