280 SL fuel injection pump works at half

[jcerazo]

Hi: I have a 1969 280 SL Euro wich was sit about 23 years. A few weeks ago I started the work on it, actually the car starts, but my mechanic says that only three cylinders are working, apparently the injection pump are not working properly. Whit the engine running, he opened the injectors and only three nozzles. I changed the spark plugs, points and condenser and fuel filter. I know the cost for a rebuilt unit it is expensive, may I have to do an additional work to solve the problem???

[Raymond]

Hi.  Welcome to the world of Pagodas. 

There have been a lot of posts about the FI pumps including one recently with a problem similar to the one you describe.  Use the search function and you'll find a lot of detailed information.  The FI pump is one of the more common issues discussed here.  Take the cautions about fiddling with the inner workings to heart, but if you get to the "tried all the other suggestions" place and nothing works, A) you will have learned a lot about the system, and B) you'll have nothing to lose by trying to take it apart.

Before dissassembly, make sure you have read the posts about removal and installation so you and your mechanic can get that right.  If your mechanic has never worked on these pumps before, be very, very, careful he doesn't overestimate his knowledge. 

If the pump has been sitting with fuel in it for 23 years, then the fuel must have turned to varnish.  Stuff will be stuck.  Rubbing alcohol does a good job of dissolving fuel varnish but you'll have to get to the parts that are stuck.  When you said "he opened the injectors", what do you mean.  Did he loosen the fuel lines at the pump or at each injector?

[jcerazo]

Thanks Raymond!! Definetly I have a lot of things to learn about MB Pagoda, a friend of mine says "a car made for the eternity". I began to read differents posts about it and I saw a problems like mine, but I a have a doubt about the type of the FI pump, because more of the post are related to 230 and 250, it is applicable for the 280?.
One of the most problem I have is the availability of parts in my country, the MB dealer do not have for those years, and if I will begin to dissasembly I run with the risk about that.
The mechanic did open each injector and no nozzles three of them, open th lines at the pump and the same thing.
Do you have some schematic or drawing of the pump?
Thanks again.

[66andBlue]

Hello jcerazo,
take a look at out technical manual there is quite a bit of information about the injection pump:
http://www.sl113.org/wiki/Fuel/Injection#Pump
And even if you cannot read German the photos in this article might be useful too:
http://sterntwiete.mparschau.de/html/einspritzung_2.html
It is very difficult to get parts for these pumps in any country not just yours and you might want to consider sending it to one of the better known repair shops here in the USA. Here is a recent discussion about repairing these pumps that could be of use to you also:
http://www.sl113.org/forums/index.php?topic=15130.0

[Benz Dr.]

Aside from a few small external parts you can't get anything from MB.
 Bosch is the place to go to but you won't get anything from them either. If they have parts they will only sell to Bosch agents or repair facilities.