M51 Diesel Problem

Hi guys, sorry to come onto a forum not specifically for the vehicle i have a problem with, anyway cut to the chase i own a 95 bmw 5 series with the non intercooled m51 engine, im having a lot of hard time diagnosing a major problem and this forum seems to have lot more useful info than the bmw boards.
Anyway, car was absolutley fine, apart form an intermmittent starter motor which i was living with until i got a spare motor.
Saturday night i pulled into asdas, car off did a shop
came back to the usual starter motor problems, normally get it started in a couple of minutes :S until now..
I tried for 20 mins or so, clicking hte starter over and hearing it disengage itself while i waited for a mate to arrive.
After the 20 mins or so the battery sounded liek it had gone flat and wouldnt turn, tried to crank the car via leads and my mates van, more of the same.
Bit the bullet and decided to tow start it, it was havign hard time starting could hear the engine turning over and trying to fire. After a few goes we got it running, had to keep the revs up or it would die. Engine making a very loud noise, like the usual diesel noise only louder. I limped home to my friends house, car is very down on power, having to drive in 3rd with a large amount of throttle to maintain 25-30mph, lots of white smoke.
i have pulled hte starter to eliminate it meshing on the flywheel and remaining engaged jsut incase, same scenario.
Also after tow starting it last night (all the same) i realised it was running much hotter than usual, getting to 50% temperature within a few minutes.
In my mind it is one of two things:
Hydrolocked the engine from trying to turn over too much, flooded cylinders then locked it when the engine stopped turning over.
or my injection timing has gone out considerably, not sure for why it would happen
Oh, last time i filled up was on thursday, had approx 10 litres in the car put another 30 litres in, im confident it was diesel and not petrol i put in. we sniffed the cap to try and confirm i hadnt put petrol in (never have in 5 years)

Anyway, im trying to come up with a plan of action, any help greatly received, thanks.

Hgf

Head gasket would seem logical for the change in performance and white smoke. However, woudlnt diesel timing also present itself in that way?
ALso bare in mind hte car was 100% fine and then when restarted a few hours later it was pretty much as dead as dead can be without actually being dead lol

Oh one more thing, the noise and smoke literally disappear when increasing engine load, ie gentle acceleration, and as soon as you ease off to maintain a speed it returns.

ALready checked oil, its black but no signs of water, and water looks clean, however it hasnt driven more than 2 miles since this problem appeared.

Sounds suspiciously like a failed pump timing solenoid

righty, here goes
decided it is an injection timing issue,
took a look at the 4th injector but it was plugged in in some ungodly place so skipped the test on that and went straight to the crank sensor, pulled it out connected a meter to it measured resistance and waved a magnet/bit of metal in front of it and it changed, tried it on voltage too and there seemed to be a change, not sure of what i was looking for, thinking resistance but either way it showed a change so i was happy
especially since...

the flywheel showed major scoring, and the scores lined up with the flywheel sensor pins...
also when the starter was removed it was missing hte bearing of the end,
got me thinking the bearing has been tapping away at the pins, and eventually driven into the flywheel casuing hte seizure as i was trying to start it, was what i was thinking was hydrolock/flat battery..
so missing a pick up or 2 could effectively mess up igniton timing
next thing is to give the flywheel a visual in day light turn it over by hand and mark all the pins and possibly run htem past the sensor make sure they register

hmm
jsut had a thought, i assumed my buggered starter motor caused the scoring in the flywheel, but it cant have as it sits in line with the ring gear :S

Anyway, stil lassuming i have damaged pick up pins on the flywheel, does anyone know how many there should be? im assuming its either 1 per cylinder, or 1 say for cyl4 tdc...

If i can work it out i may be able to use a lighter petrol flywheel

Poor performance and lots of white smoke are also symptoms of a blown turbo.

nooo its much worse performance than a blown turbo, way to severe, plus ive had the inlet tract off and theres no more oil in there than usual lol,

The way I understand this, the EDC goes to the No.4 sensor for its timing info and uses the crank sensor to confirm that it's correct. I would have thought that a messed up crank sensor would not affect timing unless the No.4 sensor is already dead. Also even with both gone the ECU should just go to limp home mode with the injector light on, not give the symptoms you've described above.

Hard to explain the physical clattering, any chance you dropped a valve? But that doesn't explain how it cleared under light pressure. I've heard that when the timing is too advanced they do clatter like mad but the question is how could that happen from tow starting?

BTW the flywheel has 6 pins to signal the crank sensor.

thanks for the info
not sure, i dont really know too much about hte timing side of the system, i agree the crank sensor and no 4 sensor have to be checked in relation to each other to calculate correct timing, im mostly working on the premise that it was ok beforei turned it off, and during trying to start it the flywheel/pickups became damaged when tryign to start it
if i had of dropped a valve (my thoughts) temperature wouldnt increase as rapidly and woudlnt go quiet under light load
ill keep you posted, am trying to source a good flywheel right now

m51dieselowner said:

nooo its much worse performance than a blown turbo, way to severe, plus ive had the inlet tract off and theres no more oil in there than usual lol,

Click to expand...

Blown turbo, not serious? Blimey, I've seen a car with a blown turbo and it was pretty serious!