e28 M535i died cold :(

[Toomas]

Hi all, im new here, it seemed like good place to ask for some help to identify some engine trouble.

Anyways its a '85 M535i (euro version, with 218hp M30 engine, no cat) and when i accelerated out of some corner it just died cold (made no remarkable sound) and wouldnt start (turned the engine but nothing else), few hours later it started up again but when i started to drive away it died again.
So i pulled it home and next day started again, i let it run like 5mins then started to play with accelerator, after some reving up and down it started to do those little booms (really quiet ones from exhaust) when i let revs down after that it kinda wanted to die but managed to pull back to idel from about 300-400.
Day after that it started up fine again but i dindt test it.

Symptoms it had before (propably still has):
sometimes would start after like 5sec of starting (used to start right up)
some shakeing at idle speeds
exhaust fumes have unburnt gas smell
some hichups during acceleration

BTW does anyone know if i could manually adjust fuel mixture (havnt really managed to find any scre for it)? And is there some easy way to test the air sensor thingy (the one right after airbox)?

Forgot to add:
Last year the distributor rotor was changed cause it wouldnt start, then few months ago i had to change spark plugs then i measured the resistance of the ignition wires and the 6 cylinder ones had similar resistance but the 7th one that goes to the ignition thingy had less resistance also the connectors inside the distributor cap were somewhat burnt (sanded them clean).

PS sorry for my english, im from Europe

Thanks for reading and have fun :)

[winfred]

best guess would be a dieing crank sensor, on that car there will be two on the bellhousing of the tranny by the starter, one reads off of the teeth of the flywheel(speed sensor) and the other reads a tit welded to the flywheel(refrence mark sensor) they are the same unit. 3 wires on each, one outer is a shield the center and other outer are signal, if i remember right the resistance should be around 540 ohms, while cranking you will be able to read ac voltage, it depends on cranking speed and which sensor on how much, usually a volt or so, if you have access to a lab scope you can read the waveform as a ac pulse. the plugs crumble and fall apart and cause problems also

[MarkD]

Hi all, im new here, it seemed like good place to ask for some help to identify some engine trouble.

Anyways its a '85 M535i (euro version, with 218hp M30 engine, no cat) and when i accelerated out of some corner it just died cold (made no remarkable sound) and wouldnt start (turned the engine but nothing else), few hours later it started up again but when i started to drive away it died again.
So i pulled it home and next day started again, i let it run like 5mins then started to play with accelerator, after some reving up and down it started to do those little booms (really quiet ones from exhaust) when i let revs down after that it kinda wanted to die but managed to pull back to idel from about 300-400.
Day after that it started up fine again but i dindt test it.

Symptoms it had before (propably still has):
sometimes would start after like 5sec of starting (used to start right up)
some shakeing at idle speeds
exhaust fumes have unburnt gas smell
some hichups during acceleration

BTW does anyone know if i could manually adjust fuel mixture (havnt really managed to find any scre for it)? And is there some easy way to test the air sensor thingy (the one right after airbox)?

Forgot to add:
Last year the distributor rotor was changed cause it wouldnt start, then few months ago i had to change spark plugs then i measured the resistance of the ignition wires and the 6 cylinder ones had similar resistance but the 7th one that goes to the ignition thingy had less resistance also the connectors inside the distributor cap were somewhat burnt (sanded them clean).

PS sorry for my english, im from Europe

Thanks for reading and have fun :)

It may be a bad connection in your DME. The 3 solder joints to the ignition coil transistor are a known failure point. I mentioned a fixed for this on a few forums some years back and someone documented it here:

http://members.roadfly.com/louielouie/dme_fix.html

This problem is not only in the 059 DME, but in any other "0 261 200 0xx"
unit also. (059 to 081 or so)

MarkD