Starting problem Help, engine runaway - PeachParts Mercedes-Benz Forum

whunter · #1 02-27-2013, 02:08 PM

multiple calls (hours) walking through diagnosis.

Please note this is a conversion 1987 300DT OM603 installed in a 1991 300GD SWB.

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Turbo breather intake hose removed, lightest possible (normal) oil trace found.

Turbo charged air (cross over) pipe removed (left off for diagnosis), lightest possible (normal) oil trace found.

Attempted to start, no joy.

Loosened injector line #1 and #2, cranked the engine, no fuel flow.

Removed the vacuum shutoff hose.

Attempted to start, no joy.

Removed ALDA, left off for further diagnosis.

Attempted to start, no joy.

Removed fuel return hose to test fuel flow (not pressure).
Looking for 150 CC in 30 seconds of cranking = 5 oz.

Output = 4 oz.
I suspect this is acceptable, the fuel tank is lower than the engine on the 300GD body making it work harder.
We discussed replacing the mechanical lift pump with an electric unit at a later date.

Random thought:
The oil pressure sender wire was removed.

Attempted to start, no joy.

The shutoff valve was removed.

Attempted to start, no joy.

The injection pump side cover was removed

Everything is visually functional.
Everything that was removed previously was reassembled/installed.

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OK, we have a tentative diagnosis of internal governor damage.

The old ALDA was tested before reinstalling and found to be broken = not holding pressure.
No start.

He installed a spare good ALDA, and the engine started instantly, revving hard to 4000 RPM before he could shutdown..

After shutdown the electric governor was unplugged.
No start.

Reconnected the electric governor.
Again, No start.

Removed the spare good ALDA, and it is now wrecked.
STOP, at this point since he has a complete spare injection pump available.

I will post links to the required procedures, shortly (quick parts run to MB).

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