71 USA 280 SL , after 5 - 10 km power loss with misfiring

[schadiqi]

Who can help me to find the problem ? I am very grateful for every answer!
 
The engine of my 280 SL (built in 1971) Automatic running in cold condition very good. Always starts well and also does not go out . If the engine is warm it beginns with misfiring and a slight loss of power. I wonder The motor rotates at very low at about 300 revolutions . Water temperature gauge is rated at 85 ° C.
 
Unfortunately I had no success so far in the repair-shops . USA Model engines (late 280s ) and there is still some very special components , which hardly one knows her in Germany
 
 Offen I heard from the repair shop ,. Rebuild the injection pump ? But why is injection pump running cold well? According to the forum I have found that there are more than 80 % of cases of non- interference on the causes
Injection pump!
 
What has been done so far:
 
1 ignition
Engine Basic setting: ignition dwell angle exhaust ( the candle picture ok) were set 2 years ago. I have read in the forum that the dwell angle should lie at transistorrisierter mm coil ignition , the setting at idle at 30-36 degrees (0.4) . I do not know if the repair-shop has done right ?The pagoda has installed a new engine from Mercedes Benz  (1st  owner) . He has till now 8000 km mileage)
 
Did last week, a new ignition coil ( Bosch 0221122001 ) built-in ( no change)
Capacitor I have ordered !
 ( Bosch 0231116062 ) (with new cap, finger , cable etc ( mechanical wear ? )
New 100 degree temperature switch (no change)
I do not have valves adjusted for 6 years !
 
 
2 air
 
The following things struck me :
 
2.1.I found out  that is in the air filter of the injection pump sucked no air in the cold or warm condition . Function of the expansion element ?
When I look in the hole where the air filter sits on slide ever ! Oh cold start where he would actually suck extra air ? ( Warm-up facility)
 
 
 
2.2 Idle is always very low and the screw to adjust the air intake ( idle ) does not react in several revolutions ?
 
 
The error lies somewhere in the air intake?
 
3 gasoline supply
 
Fuel filter I have not yet checked
Should I have cleaned all filters and fuel lines ?
 
 
The big question is where is the problem : ignition, fuel or air supply
 
As I said I 'm no expert and I am grateful for any hint or clue.  . With the repairshops in our area , I was not very satisfied so far and it has not yet led to success. ( Time and money)
 
Thanks in advance
 
regards
 
Dirk

[garymand]

2.1.I found out  that is in the air filter of the injection pump sucked no air in the cold or warm condition (THIS IS PROBLEM) . Function of the expansion element? (very possible, or stuck piston)
When I look in the hole where the air filter sits on slide ever! (? the piston is there, it should be up when cold, closed when hot.)
Oh (On) cold start where he would actually suck extra air? (YES)

2.2 Idle is always very low and the screw to adjust the air intake ( idle ) does not react in several revolutions ? (easy trouble shoot, disconnect shaft/link/rod to FIP, push shaft/link/rod down = more gas.  If idle RPMs go up, = lean.  If RPMs go down = rich.)  

The error lies somewhere in the air intake?  (Probably the WRD.  Easy/low cost problem to fix.  See this link  http://www.sl113.org/wiki/Engine/WarmRunningDevice.

(WRD needs troubleshooting and repair.  Take WRD off FIP (The FIP is OK, it works good cold)
Analyse the WRD Function of the expansion element -put WRD in 65 C water, up to 75C.  Shaft should extend, air hole should close.)

 1) I think air piston is stuck.  Just clean, light oil to prevent oxidation/corosion, assemble, put in 70C water.  Piston will close air filter passage.  2) Maybe new expansion element?

Report back for more help

[Benz Dr.]

I've seen where the housing that the thermostat for the WRD sits in is filled with sediment and this shuts off the coolant supply. Easy test is to touch it to see if it's warming up. Don't do it once the engine is hot or you may burn your fingers. 

[stickandrudderman]

Bring it to the UK and I'll fix it for you!
I have an amusing anecdote about german taxi ride that I've postyed on here somewhere. It's surprising how few german garages are able to deal with the older cars.

[garymand]

Sorry all that text is red.  I was trying to only make my answers red not the whole text.  You already know the air piston is not working: "the air filter of the injection pump sucked no air in the cold" So, take the WRD off and find out why the piston is not moving.

[rogerh113]

Hi,

I had a very similar problem on my '66.  After a lot of checking, it turned out to be the coil to distributor wire.  The wire looked fine from the outside, but when I pulled it out of the distributor cap it was clearly damaged (I think there is a resistor in there, and maybe that was what fried). I replaced the wires and all was well.  Never would have thought a bad wire would have caused those symptoms......

Good luck -- Roger

[Rolf-Dieter ✝︎]

Gary, You can change your text with a very simple edit