'85 380 SE
 

my '85 380 SE has a "Miss-fire".I have developed this problem after rebuilding the right head and replacing camshaft on the same side.(car was running fine except the head gasket went bad which opened this "can of worms")
at this point I have narrowed my problem to valve adjustment or fuel distributor.
I called my local indie shop today for a quote on a valve adjustment on the right side only.
How straightforwad is this job.I am not attempting it myself because I beleive it requires a special tool and also having the shims needed on hand.
I am waiting to hear back from the shop with quote,The counterman wasn't sure about the job and wants to talk to the tech when he arrives in the morning.
Does anyone know if the fuel dist. is the same on an '85 380 SE and a '86 420 sel ?

380SE
 

The fuel distributor from a 420/560 is different for a 380SE. Also, I dont believe you can do a valve adjustment on your car. They are hydraulic. I could be wrong though. Check your intake gasket. Does the idle get better when the car is warm? Try to narrow it down some more.

thanks!
 

My problem is more than the usual idle problem,I fixed that last year with a tune up and a bottle of "Techron"
I have a definite miss.
it doesn't change when warm
But I can hear the valves when cold,that noise goes away when car is warmed up,that leads me to beleive it needs valve adjustment.
The valves are hydraulic but can be adjusted.The "shims"must be replaced with the correct thickness shims to do this.
I have had a lean spark plug problem on the right side,and not much pressure when I crack the lines at the fuel distributor.
However I did not have this problem at all before the head rebuild.
I also may suspect plug wires/ends ?

The valve adjustment that you speak of is part of doing the head job. If you have a running problem because of this, the job was poorly done.

The adjustment made is only to the preloading of the hydraulic element. The only way this can cause a problem is if you are bottomed out and the valves aren't fully closing.

You probably have an airleak at the injector rail or the plug wires are a common problem. An experienced tech will not take long to ID either.

miss fire 126
 

I appreciate your response steve.
so far up to this point I have done all the work myself(other than the machine work) with lots of help from this site.And this is the first time I have done this job.
I just replaced the plug wires on the right side with the wires off my 450 sel ,and it is running the same.
At an Idle,if I push down on the "throttle housing butterfly" the cars dies immeadately.???
I have cracked the fuel lines coming off the fuel distributor and I get lots of pressure on the left 4 but none or very little on the right 4.
I had these lines off for over a month,could this ruin the fuel dist?
I have pulled and replaced the plastic injector rail,making sure it is in correctly.
I have sprayed wd-40 around the intake looking for idle increase.
the car starts right up everytime.but misses pretty bad.
any ideas?

rough idle
 

David,
I had a similar problem on my'85 500SEC.
It turned out to be a vacuum leak, under the air sensor plate.
There is a snorkel type piece that is an oval with a rubber piece that attaches to the bottom of the air plate. It cracks as it ages.
I had my injectors and the air rails along with this snorkel piece replaced and the idle smoothed out.
Good luck, John F.