Sticky Fuel Distributor in 1987 300E

Our 1987 300E has been in the shop for almost two months now with a fuel distribution problem. At first, we thought the fuel distributor was bad, but the mechanic took it apart and found the piston stuck with some sticky substance. Carburetor cleaner woundn't remove whatever the residue was and he could only get it off with degreaser. After getting the piston cleaned, he put the distributor back together and the engine ran fine at first, but then the fuel distributor piston siezed-up again. When he took the distributor apart, more of the sticky substance was there. He has repeated this process about five times total and the substance keep returning. He has also removed the gas tank and cleaned it out completely, along with the gas lines, but the substance is still there.

Prior to this problem, one or both of the fuel pumps were squealing and we were told that the bearings were going bad. After we had both fuel pumps replaced, we ran into this fuel distributor problem. I don't know if the two problems are related, but my suspicion has alway been that some kind of degradation product from the fuel pumps got into the fuel system.

Anyway, has anyone ever ran into this type of problem with the fuel distributor? If so, any recommendations on how to purge the system of this residue?

Thanks.

[Duke2.6]

Is there a possiblity that someone put sugar in your fuel tank?

Duke

Thanks for your response.

The mechanic brought up the possibility of sugar in the gas as he had seen it once before. We always lock the car when we leave it anywhere in public and when the car is locked, the door to the fuel filler cap is also locked. Thus, we don't feel sugar in the gas tank is the problem, but we can't rule it out 100%.

Could "bad" gas do this? If it was sugar, do you have any idea how to confirm it and, more importantly, how to purge it from the system?

[Duke2.6]

It sounds like you have some kind of fuel contamination, which could originate either with "bad" fuel from a supplier or vandalism to your car. Sugar will dissolve in the small amount of water that is usually present in automotive fuel systems and then deposit out on surfaces. Even more will probably dissolve in fuel oxygenated with ethanol. Petroleum solvents won't dissolve it, and I'm not exactly sure how you remove the deposits other than by abrasive mechanical cleaning. On vintage carbureted cars is was certainly a nuissance and required a complete fuel system cleaning, but on a KE car with all the precision machined parts, it can be a very expensive propositon.

I suggest you talk to your insurance company and see if fuel system contamination, either intentional of inadvertent is covered under your comprehensive coverage. You might also want to investigate your fuel sources and their suppliers to determine if others have had similar problems.

Duke