Bringing 280GE back to life

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MB4x4Can
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Joined: 31.08.2014
Location: Surrey, British Columbia, Canada

Hello from Canada!

I recently bought myself a 1987 280GE originally from Germany so LHD. It sat in someones field for the past 10 years so needs a bit of work. The fuel tanks are rusted petty bad and are out of the vehicle. I needed to replace the fuel pump, accumulator, fuel distributor, spark plugs, wires, filters, battery. I got it running using a fuel tank from a snow blower then it randomly stopped pumping fuel through the return line. it runs excellent if I pour fuel down the metering plate.  Anyone have any idea why fuel will not pump through the return line anymore? Do you think it needs a pressurized tank to work? This sure is one heck of a complex fuel system. Any advice would be greatly appreciated. I am tired of replacing $200 parts on educated guesses. 

Thanks

stubear334
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Joined: 25.12.2011
Location: Montgomery, AL, U.S.A.
Re: Bringing 280GE back to life

Sounds like your return line is blocked. After sitting for 10 years your G will need quite a bit of work. Mine had sat for about 10 years after the main drive shaft u/j broke & wrecked the powertrain.  Don't worry about the $200 parts, its the $800-$1,500 parts that test your resolve. Disconnect both ends of the return line & blow compressed air and check for flow. Watch the crud blow out the other end! LOOK for any crimps in the return line. Reattach and test.

Also, listen for the fuel pump to pressurize when the ignition is turned on before starting the vehicle.

Anyways this is left to be done:

Pull the fuel tank(s) and steam clean, replace the control pressure regulator mounted to the engine, replace the injectors ($20 each), learn how to use a fuel pressure gauge & purchase the Bosch fuel injector book.

Also, there are several fascinating Youtube Bosch training videos. After mastering CIS injection, you can work on everything from Porsche's to Ferraris.

Stuart

MB4x4Can
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Location: Surrey, British Columbia, Canada
Re: Bringing 280GE back to life

Thanks for the replies everyone. This fuel system has me confused. I think the no fuel going back to the tank was a minor leak off of the accumulator. Now... it still wont start on its own. If I prop the metering plate open with a screw driver it starts up really nice runs idles ect. If I hold it full open it will accelerate nice and stay running let off the gas dead again. Given all the parts i've replaced I'm pretty confused now. Recommendations as before are appreciated. 

Russ280
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Re: Bringing 280GE back to life

You're testing my memory cells now but an educated (well that maybe an exaggeration!) guess would be:

The metering plate relies on fuel pressure to open/position itself at idle, you are by passing that when you open it with a screw driver. As I assume you are starting the vehicle from cold I would suspect the cold start valve. Failing that I would guess fuel pressure. To figure that out you will need some test equipment.

When you first turn on the ignition you should hear a relay operate from the fuse box area and the fuel pump run for a few seconds and then stop. If it doesn't it will be the relay. These fail quite often and are pretty cheap. I can't remember the code for them but you'll find that online.

As stated above there are online resources for CIS. Once you know how it operates it's pretty simple and a great system. Unless you're lucky to find a mechanic who know the system you're better off figuring it out for yourself though. 

gav.helme
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Re: Bringing 280GE back to life

Russ280 wrote:

You're testing my memory cells now but an educated (well that maybe an exaggeration!) guess would be:

The metering plate relies on fuel pressure to open/position itself at idle, you are by passing that when you open it with a screw driver. As I assume you are starting the vehicle from cold I would suspect the cold start valve. Failing that I would guess fuel pressure. To figure that out you will need some test equipment.

When you first turn on the ignition you should hear a relay operate from the fuse box area and the fuel pump run for a few seconds and then stop. If it doesn't it will be the relay. These fail quite often and are pretty cheap. I can't remember the code for them but you'll find that online.

As stated above there are online resources for CIS. Once you know how it operates it's pretty simple and a great system. Unless you're lucky to find a mechanic who know the system you're better off figuring it out for yourself though. 

I will second all that, post or PM your chassis number and i can give you the Fuel Relay numbers etc

Gav

MB4x4Can
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Joined: 31.08.2014
Location: Surrey, British Columbia, Canada
Re: Bringing 280GE back to life

Hi All. Been a while since my last post this project, it has been on hold for the winter however thanks for the input. Gav my Chassis number is 46023317051XXX. I am at the point of considering replacing the engine with another M110.  I have found a running one from a 1981 280CE with aircon which my GE doesn't have. Does anyone think the swap should contain any hidden problems? From first inspection the 81 has a far more rudimentary EGR system than the 87 and the GE has an oil cooler where the CE doesn't. 

A side note if i may from the previous two comments. I understand from some searching that there are differences in warm up regulators but they are minor. The original one from this car had been taken and I replaced it with one from a early 90s 320. Could this cause the fuel pressure to force the metering plate closed on start up? The most confusing thing is that this set up has run and driven (slowly around the driveway).

Thanks again.