My 1978 W123 280CE Mercedes-Benz Engines Hesitates

[Edmund]

My 1978 W123 Mercedes-Benz 280CE got fully restored (including the engine) less than a year ago. Recently the engine hesitates. The worst case is that it can only go up to 30km/h. The mechanic told me that I was running it with extreme low fuel level and therefore sucking up the residue at the bottom of the fuel tank. After that the fuel pump, the fuel hose & filter were replaced. The fuel distributor & injector were also cleaned up. However, the situation only improved but not solved. When I accelarate hard, the engine is still choking. Even if I accelarate "smoothly", the car cannot go above 100km/h. Should I consider to replace the Fuel Tank or if there is anything I can do to solve this problem completely? Please help me...

 

[spanners]

Poor acceleration.

It could be a blockage in the fuel return line.

Does the engine plutter when you rev it hard from idle if the car is staionary? If it does, then disconnect the return line from the fuel distributor and divert into a jug or similar container. Then start it and rev it.

If it revs OK, you have identifed the return fuel line and and if it still splutters it clearly isn't the return line.

 

[Edmund]

Thanks for your suggestion.

The engines seems running OK when I rev it hard from idle if the car is staionary. The choking problem only happens when the transmission is engaged.

Please help me if you have any idea as I do not want to make unnecessary parts replacement.

 

[TimN]

Have you totally eliminated the timing. If the engine has been completely disassembled then when rebuilding it the ignition timing and the timing of the camshaft to the crankshaft may not have been done correctly. It won't cost you a penny to check! Also is the butterfly valve on the throttle opening properly. They may have knocked out the adjustment on the inlet flat which would cause it to run lean or rich.

 

[Andy]

Hi


It sounds to me that firstly you get the engine tunned correctly. Making sure the emissions are correct. Then check the fuel pressures & check that they are correct & the correct delivery rates are attained. The problem will more than likely in the fuel system. But a good garage should be able to check the spark lines on the ignition system with the aid of an oscilloscope. But check that the fuel pressures are ok. Changing and cleaning stuff will not help. You need to find out what is ACTUALLY happening with the above.


Regards


Andy@ www.mercedesservicing.com