Author Topic: Fuel Injection Pump Problems 280SL  (Read 8209 times)

fabricio

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Fuel Injection Pump Problems 280SL
« on: June 19, 2011, 16:44:51 »
hello do you know something about problems in the injection pump  that can  cause  all the spark plugs get clogged after 10 minutes the engine is running and  then the engine stalls. I clean the plugs and starts smooth again  but repeats the problem again.  
I just replaced the fuel injectors.

thanks
« Last Edit: June 20, 2011, 09:57:55 by 280SL71 »

mdsalemi

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Re: FUEL INJECTION PUMP PROBLEMS 280SL
« Reply #1 on: June 19, 2011, 17:12:03 »
Guessing you are too rich.

Go to our Tech Manual and follow the instructions for linkage set up.

Ensure you do the "split linkage" test as well.
Michael Salemi
Davidson, North Carolina (Charlotte Area) USA
1969 280SL (USA-Spec)
Signal Red 568G w/Black Leather (Restored)
2023 Ford Maverick Lariat Hybrid "Area 51"
2023 Ford Escape Hybrid
2024 Ford Mustang Mach Ex PEV

ja17

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Re: FUEL INJECTION PUMP PROBLEMS 280SL
« Reply #2 on: June 20, 2011, 01:06:34 »
Hello,

Good advice from Michael, also check to make sure the WRD (warm running device) is not stuck. What is the history of the car?
Joe Alexander
Blacklick, Ohio
1969 Dark Olive 280SL
2002 ML55 AMG (tow vehicle)
2002 SLK32 AMG (350 hp)
1982 300TD Wagon turbo 4spd.
1963 404 Mercedes Unimog (Swedish Army)
1989 flu419 Mercedes Unimog (US Army)
1998 E430
1974 450SLC Rally
1965 220SE Finback

fabricio

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Re: FUEL INJECTION PUMP PROBLEMS 280SL
« Reply #3 on: June 20, 2011, 04:08:24 »
thanks mike and joe

The history is that the car was stand for 7 years and it started perfectly but after a little use it begun to get clogged so i found out the fuel tank had some rust, opened sanded and welded again. It happened 13 years ago and did the same and did well.
I just have changed the fuel injectors because a mechanic tried them in a bench and said they were bad. The problem still the same. The spark plugs get well soaked with fuel and the exaust is coming out with black smoke and strong gas fumes.
I read the technical manual and dont understand the split linkage test.

mdsalemi

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Re: Fuel Injection Pump Problems 280SL
« Reply #4 on: June 20, 2011, 12:00:14 »
Fabricio,

Wet plugs, black smoke, gas smell=too rich, for certain.

The question is why?  If your car sat for 7 years, this is not good.  My guess is something in the fuel injector pump is causing the over rich condition, OR, perhaps your cold-start injector is "always on", dumping extra fuel in when you do not need it.  When the engine is warm that cold-start should NOT be energized and no fuel should be coming out.

I'll have to go to the Tech Manual and see if the split linkage test be revised for better understanding.

The concept of the test is simple: at various RPM, Idle (<1000); Midrange (<2000) and High Range (3000) you separate the linkage so you have individual control over air (that is the top part) and fuel (bottom part).  You run the engine at these RPM and see if the engine wants "more air"; "more fuel", or is "just right" at the various RPM's.

So, for example, push down the linkage to acheive 2,000 RPM; separate and hold the parts together.  Now, add more air by leaving the bottom linkage steady and pushing down the top; this opens the air flow.  The car's RPM should go down.  Do the same with the lower linkage, adding more fuel; the car's RPM should go down, too, on a well-adjusted system.

If the RPM's go up with more air, you are too rich.  If the RPM's go up with more fuel, you are too lean.  That is the essense of the test, to determine where you are rich/lean at the full range of RPM.

Now adjusting it all is a different story.  There are plenty of places to adjust everything and plenty of places to mess it up.

We know you are rich because of the smoke and wet plugs.  My first guess is the cold start; second guess is something in your pump is stuck.  Try testing the CSV, when the engine is somewhat warm, remove the electrical connection to the CSV.  Maybe the relay is stuck on?
Michael Salemi
Davidson, North Carolina (Charlotte Area) USA
1969 280SL (USA-Spec)
Signal Red 568G w/Black Leather (Restored)
2023 Ford Maverick Lariat Hybrid "Area 51"
2023 Ford Escape Hybrid
2024 Ford Mustang Mach Ex PEV

ja17

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Re: Fuel Injection Pump Problems 280SL
« Reply #5 on: June 20, 2011, 13:09:00 »
Hello,

Check the WRD on the injection pump. It is easy. Remove the small round WRD air filter (check to see if it is clogged). Next leave the WRD air filter off and start the engine. Air should be rushing in the WRD when the engine is cold. The rushing air should stop after the engine is warmed up. If the rushing air does not stop when the engine is warm, dis-assemble the WRD and clean it up so it moves and works correctly.
Joe Alexander
Blacklick, Ohio
1969 Dark Olive 280SL
2002 ML55 AMG (tow vehicle)
2002 SLK32 AMG (350 hp)
1982 300TD Wagon turbo 4spd.
1963 404 Mercedes Unimog (Swedish Army)
1989 flu419 Mercedes Unimog (US Army)
1998 E430
1974 450SLC Rally
1965 220SE Finback

bonanome

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Re: Fuel Injection Pump Problems 280SL
« Reply #6 on: June 21, 2011, 13:33:50 »
 Thanks a lot mike,
I will work on it this saturday but i have to tell you also that i changed spark plugs and two of them were dry of fuel it seems that these two dont get gas  and the injectors are new, what do you think

I am fabricio`s father.
 

fabricio

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Re: Fuel Injection Pump Problems 280SL
« Reply #7 on: June 22, 2011, 03:49:18 »
THANKS MIKE AND JOE.
I FOUND ANOTHER PROBLEM GAS/PETROL IN ENGINE OIL 
I HAVE POSTED IT!

mdsalemi

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Re: Fuel Injection Pump Problems 280SL
« Reply #8 on: June 22, 2011, 10:53:54 »
THANKS MIKE AND JOE.
I FOUND ANOTHER PROBLEM GAS/PETROL IN ENGINE OIL 
I HAVE POSTED IT!

This is probably not another  problem, but rather just another result of this over rich condition.
Michael Salemi
Davidson, North Carolina (Charlotte Area) USA
1969 280SL (USA-Spec)
Signal Red 568G w/Black Leather (Restored)
2023 Ford Maverick Lariat Hybrid "Area 51"
2023 Ford Escape Hybrid
2024 Ford Mustang Mach Ex PEV