'81 320/6 Starting Issues

[e21paddy]

Hello all,

Recently I was travelling down the road at about 60mph when I had a sudden loss of power and had to nurse the car to the hard shoulder.

Symptoms: the car would just basically turn over and turn over, no smell of petrol through no matter how much I choked or tried to flood. No start. The car was getting spark but barely any petrol spray in the carb.

I checked the inside of the small fuel pump and it had all kinds of crud in there, along with a perished seal.

Reactive maintenance: Changed out the fuel pump, distributor cap, rotor and spark plugs (they were due to be changed).

Now the same thing is happening, even though it's getting spark and fuel. I had a jumper pack hooked up to give it the best chance, and i got a sense it was near starting with the choke out. Once I let it turn over a while, it sparked up and was idling fine, albeit very rich (stain of fuel from exhaust on the drive). I was about to drive it to my mechanic, when I put the choke back in it immediately died. Hasn't started since.

Thank you in advance!

Car: 1981 320/6 with Weber carb.

[Jeroen]

Everything clogged up with residue from a hose being eaten internally, or with dirt from your fuel tank? Do you have an in line fuel filter in the hose running towards the pump (feed line)? These help keep things clean and you'll be able to see it when you have dirt build up. Perhaps your current fuel filter is clogged, or the pickup element inside the fuel tank?

[e21paddy]

Hello Jereon,

I also change the inlet and outlet fuel pipes. The carb itself is getting fuel, a healthy squirt into the carb!

I’ll install a small in line filter to see if it’s collecting any crap from the tank or pipes!

Could it be that the carb is tuned for the spent pump that was half working? Now that it’s grtting more fuel it could need to be adjusted?

[Jeroen]

Definitely likely it needs adjustment, you may be over fueling now. Spark plugs wet after start attempts?

[e21paddy]

Yes, smell of petrol. I’ve tried starting by just leaving the choke out a little, but this could also be too much I suppose. I will try and adjust and come back!

[Peter V.]

With all the shit which was going into your carb I think you need a good cleaning up in there. Make sure al your air nozles inside are clean. You may have fuel enough but when you have no air it wil do almost nothing.

[e21paddy]

So just a quick update:

I sent the car to get it’s timing done.
Changed sparks, distributor cap and rotor, timing and water pump.
While installing the distributor it was noticed that the shaft had some play, and thus when timing it, it had to be advanced. This means it’s running a little rich. Is this a detrimental issue, should I change this immediately or will it run for a bother while (how long is a piece of string!).

Two options: service (I haven’t seen anywhere that does this in Ireland)
Buy a new one (5-600 quid) which, so close to Christmas, I do not have.

[Jeroen]

And a good used example from Fritz's Bits or the likes?

[e21paddy]

Tried him after you suggested Jeroen, he said he has laid his hands on every M20 distributor, but cannot seem to find the one I’ve given!

There is a Dutch website called ADV automotive, has anyone heard of them?

[Jeroen]

You can try them but I don't expect any miracles. Why not put up a wanted ad here on the forum and please do add the Bosch part no. Together with some of the other Dutch guys I think we have a score of them so who knows one of us has the right one.

[e21paddy]

Just put it up in the wanted section!

Seems even a new one is hard to find with that particular Bosch OE number! Seems strange that they would have numerous Bosch part numbers for the one BMW part number? And if so, what is the difference between all these, can they be adjusted to suit?

[Jeroen]

BMW throws their part nos on one big heap so they only have to stock one model but I suspect mainly the vacuum advance/retard specs to be different. I'd defo try to get the right model.

[e21paddy]

That’s proving to be very difficult. I’ve been delving a bit deeper into it, and it looks like there are Bosch repair kits for them. Finding the right kit could be the issue though.

It doesn’t look like a hard job (famous last words). But my back is up against the wall at this stage!

I appreciate the guidance and information here, it’s the best website I’ve seen for E21 info

[e21paddy]

Short video of the play in the distributor shaft on removal.

Also I found a company in the UK who do reconditions for £155 (175 inc. cap and rotor).

[Jeroen]

Better do a full recon then, then you're also sure your vacuum advance is up to standard.