1985 325e intermittent rough ride and black smoke?

[iceshark]

Wierd, Car will idle smooth and run fine and then all of the sudden chug for life at idle and miss as I try to give throttle and black smoke will come out. Then after alittle while I can get it going like it never happened with no black smoke.

Then sometimes (allot lately) I will notice a a big surge on and off at driving speeds. Feels like when you have an under powered car and air conditioning makes it sputter when engaging on and off while driving. (I am not using AC)

Today it got really bad. I was at light and started to sputter. I stepped on gas nad it was missing something fierce and a cloud of black smoke came out. Finally after goosing the throttle it started running fine and smoke was gone.

Any ideas?

 

[iceshark]

fixed my belts tonight and drove around for an hour with hardly a miss. However I did feel some hiccups while shifting into 3rd. Also can see some very black smoke coming lightly from exhause while at idle. Idle is smooth however. Also I removed plugs and most had some black on one side. Not oil soaked but smelled of gas like running rich. The last plug seems to be frozen in place. I can turn some but its very tight and does not seem to be coming free. Left it alone for know. Dont want to deal with that yet.

I dont have a Bentley.

This car was sitting for 4 years and I have changed all belts and oil. However the gas was old. I have run a tank of new gas with a can of Seafoam thru it. Could it be filter? Cant even find a gas filter.

Thanks for the help!

 

[E30m42cab]

It sounds to me like that plug that has been in there for more than 4 years, it won't turn without stripping the head, so its been left in for a reason. It's probably misfiring, and the valve seals are shot, causing oil to leak into the cylinder from the topside. Check all your plug wires and make sure they're firing, and change those old plugs for sure. Also, since it's been sitting, make sure some little furry creature hasn't made a home in the throttle intake boot or air filter box (change air filter). Check your ground too (often a braided wire from the engine to the top body of the car or shock tower on the passenger side.) Your other cause of oil black smoke might just be a bad cylinder... bad compression becuase your rings are shot. Happened to my 86' 325e. Your valves are probably a mess... either sticking or in desperate need of adjustment... (clickety clack).
The fuel filter could also be clogged a little... you'll find it on the inside of the frame rail under the PS reservoir and the brake booster/MC.

 

[iceshark]

I have checked wires and all including the last stuck plug are firing. I hope your wrong about the valves. Yikes. I would think it would be consistant if the valves were leaking and bad.

Example, Today it drove no smoke and great all day. Then I stopped at store and when I went to leave it was cutting out horrible at idle with black cloud of smoke. Ran okay after awhile but still spewed black smoke between gears and at rough idle.

So its not all the time?

 

[Doughnut]

Does your 1984 325e have a catalic converter?

If it does sounds like that to me.

 

[iceshark]

It does have a CC. Let me know what your thinking?

 

[dbmw]

it could be that you have a clogged bmw catalytic converter. try also checking for some leaks.. a bad oxygen sensor signal, airflow sensor signal or MAP sensor signal that is upsetting the air/fuel mixture. give us an update of what other things did you notice.. good luck

 

[E30m42cab]

Your best bet might be to have it plugged in to a code reader and see if the MAF and o2 sensors are giving you a good mix.... but it sounds to me like you're missfiring, and burning oil because of bad vavle seals.... A clogged cat is definately something to look into.
When you say it smokes, I'm assuming its not pretty... like a big cloud! I don't see how it could be intermittent. I'm stumped.

 

[iceshark]

I am baffled as well. I disconnected the big cylinder thing on passenger side on top of rear valve cover near firewall. It had a square plug with 2 prongs in it. It seems to be a main vacuam component. The motor started immediatly reving up and down. No smoke could be seen.

I have checked air filter and all vacuamm hoses.

What I notice is that when driving it while its running smooth I smell and see no smoke. My friend behind me sees none as well. Then when it starts to sputter and miss and I gun it, a big constant cloud of black smoke will come out. Plus come out while I drive.

After awhile it will start running good again and I see none or little black smoke.

Also, Any ideas how to get the stripped tight plug out. Can head be heli coiled?

Another thing I noticed today was that when I stop the car and let it idle I may see no smoke. But after a minute it will start to come out lightly to more depending if its missing.

The idle will go up and down some just like the power going up and down some while at crusing speed. Kinda like a momentarty push on the accelerator.

I looked for O2 sensor and cant find it. Manual says on exhaust near manifold. I dont see it?

 

[E30m42cab]

On my old '86 325e, the O2 sensor was down under the car closer to the CC, not visible from the engine compartment. That thing you pulled the plug on was your ICV (idle control valve).

Black smoke is (as far as I can tell) oil burning... but I don't see how its intermittent.

I probably would have hit the thing with a hammer by now.

 

[Big Daddy]

Why is there smoke coming from my exhaust?
Blue smoke usually indicates that engine oil has entered your exhaust system. You should have your vehicle checked as soon as possible. Black smoke means that your air/fuel mixture contains too much gasoline. Your oxygen sensor or engine control computer could require adjustments. White smoke is usually just steam; however, if accompanied by a strong odour it could indicate that you have an internal coolant leak which should be promptly treated.