Update on 1984 325e with Intermmittent problem. Black smoke.

[iceshark]

Well I went ahead and fixed the 3 V belts by replacing them today. I then started car and it ran smooth but did have some black smoke. I drove to get new gas and when I went to restart It did the surge and not idle thing. After gunning it some I was able to get it back to idle and drive home. I noticed black smoke on way home.

I had taken the front 5 plugs out early in week as you remember and saw the platinums were half dark and half good color of brownish white.

Well taking a chance I remembered that although it can be bad for the head. Sometimes a stuck plugs only chance is when motor is warm. Seeming that I had not driven the car but up the block and it was only warm. I sprayed some easy out spray and let seep for a half hour.

Then I tried again. What do ya know I was able to get that last plug out. The plugs threads look good and showed no metal! YES! So hopefully I will be able to put some thread goop on new plug and get it in and not repeat the problem.

The guess that I would find an old plug was accurate. It was a non platinum Boshh plug with green stripes. Probably 20 year old, Who knows! First thing I notice is its dry but black as coal. Well then it gets more interesting. I go ahead and remove the other 5 plugs and guess what!? They were no longer running normal like last week. They all were DRY but black as coal. No oil or wetness present but all black as they can get.

Now I am not an expert but as I remember over the years that not all valves would have went in last week. Each cylinder is independant. So I am hopeful this shows its not a valve or ring problem.

The question now becomes. What the heck Do I check next?

Lastly, When pulling off the middle wire I accidently pulled wire out of sleeve. These wires were just put in by last owner and were expensive. Did I just ruin the wire or can I just put the wire back in. I am assuming the worst for the wire.

Thanks all!

 

[Doughnut]

If you are refuring to the spark plug wire (the part inside the plug that holds onto the spark plug nipple) and you haven't pulled the metal off the end of the wire you should be able to just slip it back in no worries.
Pull off your rocker (valve cover) and inspect the cam, lobes should be shiney with no excessive wear more inportantly towards the top of each lobe.

Anyone else feelin' mushroomed cam lobes?

 

[iceshark]

I will look at that. But again, A week ago no carbon or little on other plugs. Now black as can be. How about the airflow meter? I have read some other posts with same symptoms that turned out to be this thingy.

Oh and the end of the wire was bare. Like if you took the wire and cut off a section. I looked in cup and see the metel clip.

I have read these may the the main culprits.

On an E30, some of the things that can cause it to run rich ar:
- coolant temp sensor bad, DME always in warmup mode
- fuel pressure regulator bad, causing fuel pressure to be more then low 40ish psi
- bad or mis-adjusted air flow meter
- bad O2 sensor
- also, stock plug wires normally last 150k-200k miles, and normaly you should replace with stock ones, the aftermarket ones are usually more expensive and lower quality then stock in this case.

 

[Aquaro]

Re black smoke..

Giday from downunder..
Sounds like your airflow meter is not getting power if you changed the belts you may have inadvertidly disconnected the clip to the air control box in the middle of the air intake..
With you finding it hard to start it would have to build up vacum before opening the valve far enough to get enough air to run..
To prove this point try disconnecting the air intake and hold the valve on the air box open so the engine gets air then start with no throttle.. It will not matter how far the valve is open cause you have the throttle valve further towards the manifold to stop it getting away from you..
Regards Aquaro

 

[Doughnut]

Giday from downunder..
Sounds like your airflow meter is not getting power if you changed the belts you may have inadvertidly disconnected the clip to the air control box in the middle of the air intake..
With you finding it hard to start it would have to build up vacum before opening the valve far enough to get enough air to run..
To prove this point try disconnecting the air intake and hold the valve on the air box open so the engine gets air then start with no throttle.. It will not matter how far the valve is open cause you have the throttle valve further towards the manifold to stop it getting away from you..
Regards Aquaro

Good test to run mate.

 

[RBThompsonV]

Update....MAYBE getting closer to a fix...
replaced fuel pressure regulator and cleaned AFM contact....it seems to have changed the issue... i can actually throttle it and she'll run up in RPMs but still stalls...backfires, buy MUCH less...can someone give me accurate test readings from a knosn good AFM?
may also be DME, but i'm unsure which of the boxes it is/exact location...any help?

 

[Kirby]

Black sooty plugs mean you are running rich. With all the trouble you are having, I am not surprised that the new ones are black. This does not mean you have a major mechanical problem at this point in my opinion. Still a tuning issue.

I have heard people claim that Platinums in older BMWs are a problem. If you are using platinums of any type, I personally would go back to Bosch regular old plugs until this problem is sorted out.

Sorry,don't know the DME location on E30s.

 

[RBThompsonV]

regular old plugs were fi3st thing in...

 

[Doughnut]

Your ecu is located on the glove box side, in your left hand drive car.