Right heres the story..Had been driving the 635 for a week no bother.Parked it outdoors overnight raining(its been out in the rain beforeno problem).Went to start it next morning and it seemed to be down on a cylinder immediately put it down to condensation or dampness so left it there planning to look at it the next day.

Next day went to start it and it seemed to be worse(down on 2 or more cylinders) then it progressed to turning over and making an attemp to start but not actually starting so i got straight at it off with the distributer cap and out with the damp start spray( cap was bone dry along with plugs and everything else i could think of)

So out came the credit card and joe duffy`s ph number.

New plugs,distributer cap,rotor arm,plug leads and feul pump..OUCH.

Still no luck.i gave up and up to a mechanic friend of mine it went..

Since then its had new fuel tank,another fuel pump(incase first one wasnt giving enough pressure),all new fuel lines,assorted relays and fuses and a new fuel sender unit...OUCH,OUCH.still no luck

Next step is new distributer unit and E.C.U.(i dont think its either.

There is fuel and there is a spark at all the plugs.

The mechanic is not a half arsed chap and is usually excellent with the older cars but we`re both stumped by this..

Before i bring myself to my knees and buy the distributer and ecu does anyone have any ideas or suggestions..

The mechanic has tried just about everything and there is no crankshaft sensor on my car..

Sorry for the long post but im desperate and have even thought about putting it on ebay no reserve.

THANKS

P.S its a 1980 bmw 635csi manual,original irish car

Have you dun a compreshen check, Pluss check to see if there is a injection pulse at each cylinder? You can get the injecters cleaned witch is well worth doing.

Hi there

all of the above is worth checking, as a spark doesn't mean it's strong enough to fire up the car. Did you take out the plugs again to see if she gets flooded? The fuel pressure can be checked quiet easy by connecting a pressure tester in the fuel line at the pressure regulator in the engine bay. Are all the temp sensors working ok?

Airflow meter and lastly idle control valve (also the car should start with a fully depressed trottle [careful you have to let go as soon as she fires to not race the cold engine]) and lastly whats the voltage on the battery and does the battery collapse under cranking?

1980 635i, did you change the 10mm low pressure fuel line between the tank and the pump, if it's gone porous ( it might look great) it will draw in air with the fuel and give you poor pressure, mght also be the vaccum controlled fuel bar pressure regulator on the return line to the tank  

Lastly and somewhat unlikely check the  expansion fuel tank built into the fuel pump cradle at the rear of the car, these can deteriorate internally and can give a partial blockage, I'd still bet it's a fueling issue.

Best of luck Tom

First..return fuel line etc.replaced(had that problem last year)all fuel lines now replaced..coil working..temp sensors replaced..airflow meter good..battery good.

Ill take notes on the other stuff(pressure test/injector pulse,etc.) and check with the mechanic if he done them.

@ CURLEY..I thought it was fuel also which is why i went for new tank/lines/pump/ and everything else fuel related and now im lost as to what it is.

Ill keep posting as i go along..

On another note i bought myself a new toy a 1985 bmw 525i,left hand drive on german plates and it drives as good as new(for now).

P.S thanks for all the replies and suggestions.

Luckily enough its an original irish car,demo car for bmw on the naas rd when it was new(nice reg too "635 AZJ").

On an update note i was talking to the mechanic and fuel pressure test was done(thats grand) and pulse at injectors fine.

I think ecu and distributer unit are going to have to be got.

P.S @kbannon,did you mean the german 525i? i bought that for an engine for my 325touring but it is in so good nick that i cant bring myself to break it so im going to drive it (on trade plates ) for a week or so and then ill either  use it for the track or store it with the rest of `em. 

It's a big conversion shoving the e28 m30 525i pony into the e30 so I'll be interested to see how that progresses.

The 635i I purchased was also a non runner with a deffective auto box. My issue was fuel related with the 10mm hose gone porous along with a fuel pump that wasn't delivering enough pressure for the injectors, two replaced and its purring like a kitten, Now it just a matter of reparing the auto box, only got 1st N and reverse along with a broken kickdown cable. It may be related but I'm guessing its a blockage.

Best of luck with it, Curley

@ curley,when i first bought mine it was a non runner also, it was the same problem as yours so thats sorted,every fuel line and component is brand new at this stage,the only thing left as far as fuel is concerned is that a bit of dirt may have got up to the injectors so the mechanic is going to clean the injectors when he gets a chance..though at this stage we`ve moved to thinking its an electrical fault.

As for the m30 engine going into the e30touring,im going to scrap the touring(too many cars and not enough time too give all of them).

LOL..ive just seen the amount of cars you have,looks like we have the same disease