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82 380SL rich/lean problems

12K views 23 replies 7 participants last post by  cjloy 
#1 ·
Finally the heat is gone in Alabama and I can start working on my car again in the garage.

I bought my car last year and replaced all the normal stuff: cables, plugs, fluids, points, NEW warm up regulator, ect....

The problem now is this: When I start the car cold is runs like it is supposed to run, engine is responsive en the transmission shift perfect, it only smokes a bit (too rich?)
I can run all day like this, but......

When i turn of the engine and start again.....it is sluggisch, hardly accelerates( to lean?), and the transmission shifts with a jump. It also looks like the economymeter pegs in the red much quicker.

I think it is vacuum related, I checked all the hoses and connected everything like I think it should be, but there seem to be some discrepancies in different manuals about how too hook up all the hoses.

Particularly the WUR has a lot of different options to hook up, wat is the correct one for a 1982 380SL, where does which hose go, to which manifold outlet? How many hoses go to underneath the breather to where you cannot get to?

Any other suggestions are welcome, maybe it is not a vacuum problem....

thanks
 
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#5 ·
sorry for not replying earlier, I thought I would receive a email if there was a reply....

Car has 97000 miles, my mercedes mechanic told me that (he did not see the car yet) he thinks it will be a vacuum advance problem. So probably a vacuum leak somewhere.
 
#8 ·
I can't think of anything that should change by just turning the car off and then back on, which should effect the performance and the transmission. There is a vacume line that comes off the back of the engine, right hand side that runs down to the transmission modulator that is known to deteriorate, and that would effect shifting, but that should occure all the time...Let me think about it for a while, I'm at work right now, but in the mean time,. check out this thread for vacume diagrams, this should keep you busy for a while.....

http://www.benzworld.org/forums/r-c107-sl-slc-class/1453268-107-vacuum-diagrams-6.html#post4361216

Tom
 
#13 ·
The transmission modulator has been checked and works ok. But seems to get not enough vacuum from the manifold after the second engine start


This part makes no sense to me. The modulator's vacuum source is directly from the manifold. If the modulator itself is good, any shifting issues would seem to be a throttle and or shift linkage adjustment issue.




I think.
 
#14 ·
ok, so why can it be that after the first start the car shifts perfect continuously. Untill i shut down and start again. Is there extra vacuum provided when cold? After the 2nd start it is also very slow on the accelerator. So it goes from very responsive and shifting perfect to slow and jerky on the shifts after I shut it down for the first time. No difference if that is after 5 minutes or 3 hours.
 
#19 ·
What happens if you start the car, then imidiately turn it off, then restart? Does it run normally with the rich fuel, or does it defer to the rough, no power mode. Just wondering if it is electrical causing the vacume isse, or if it's temp related??/
 
#20 ·
rowdie said:
Nope. It is connected to manifold vacuum. If the passenger door and fuel door don't lock with locking the drivers door you have a leak somewhere. Not until 'the '86 MY was there a separate system.


While cjloy's earlier engine management and central locking systems do have a common vacuum source, the locking system is separated by a check valve. As long as that central locking valve has not failed a leak down in that system will not effect the engine management vacuum controls.
 
#21 ·
rich/lean problems solved

After a year of struggling I finally decided to drop my car off at the mercedes dealer and let them figure out what is wrong. It took em a few months but they found it.

Bad gastank which clogs the warmup regulator and thus loosing vacuum and/or fuel pressure, sounds easy but I quess with these cars sitting for a while, replacing/cleaning the gastank is a must...

Finally it drives like it should.

Now I only need and original oxygen sensor and harness for my 82 380SL.
The one on there is connected with the inner wire only. My mechanis says it is to fast after warmup and needs to be replaced
 
#23 ·
The single-wire type O2 sensor is correct for my car and thus yours, too. The other wires are for heaters which bring the sensor up to operating temp; ours uses the exhaust stream to heat it. It cuts in when the coolant temp reaches 60C I think (might be 60F). You should hear your frequency valve buzzing after the sensor warms up and the ECU takes over.

If you have a sensor with multiple wires on it then you should get it replaced. They're cheep, $50 or so and they make all the difference.
 
#24 ·
I quess mine is a single black wire to but has the big black plastic connector on it with a inner and outer core. I thought that was a double wire one. the cut of both connectors and put together. my mechanic says that i need to get it back to original to have it work correctly.
 
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