Mercedes: No Start for 89 190D 2.5, answer mark, water in the fuel

Question
QUESTION: I have a 89 190D 2.5 (non-turbo)that I started last week and ran for 10 mins doing errands.  I shut the car off for five mins and tried to restart and it turned over but would not start. I have owned this car for 8 years and have never had this situation before. Had the car towed home and I checked the glow plugs with Ohms meter and found three bad plugs.  While this would make it hard to start when cold...with the engine hot the bad glow plugs should not have been an issue.  I will change out the GP's but think there may be another problem that I should be looking for.

Thanks

Mark

ANSWER: Mark,
Yes the glow plug would make it difficult to start cold. But hot should fire right off. With a diesel it is either loss of fuel flow, or loss of air intake. Have you emptied the fuel separator and filter/ If not you may have water in the fuel and that will definitely not fire off. Or, you may want to check the kill solenoid. If it is closed then you are not getting air to allow the fuel to atomize.

When you turn off the vehicle it engages a circuit to starve the engine of air and that is what stops the combustion.
Hope this helps.
Rob



---------- FOLLOW-UP ----------

QUESTION: Rob,

I did check for water in fuel and its clean but will replace the separator and fuel filter as a precaution.  Is the "kill solenoid" electrically driven or does it use vacuum to close the air intake butterfly and is there a separate solenoid to shut off fuel when key is turned to off?

Thanks
Mar

Answer
Mark,
I have done a little research and found this suggestion: This may be more likely the problem. If you you try the hand pump and get these results, then it most likely is the strainer.

Hello I'm an M.B. tech.. It sounds like the fuel strainer is clogged. It is a very common problem on M.B. diesel engines of that era. Diesel fuel develops algae inside the fuel tank and after a period of time it clogs the strainer. The strainer is at the bottom of the fuel tank where the big fuel hose attaches to the tank. The hose unscrews from the strainer and then the strainer unscrews from the tank. There is a filter on the strainer that can be cleaned and reinstalled. In the engine compartment there is a small primer pump that is by the fuel rack inline with the feed hose from the tank. If you turn the knob(clear or white plastic) on the pump it will retract allowing you to use it as a hand pump. If when attempting to retract hand pump it is sucked back down and will not stay retracted that means you have a restriction in the line- your fuel strainer is clogged is the most likely problem. replace both fuel filters during repair for best results.

If this does not cure your no start problem, then the vacuum pump diaphragm or shut off valve may be the problem.
Rob