Anyone here have any experience with troubleshooting a fuel suction leak? How did you troubleshoot the problem and what did you do to fix it? I have reason to believe that our diesel engine might have a fuel suction leak.... I don't know for certain but this the direction that I'm leaning towards.

I have some ideas on how to tackle this, but would like to hear from someone that might have some experience with dealing with this sort of thing. Thanks in advance.

What type of locomotive or engine is this?

GE FDL-12 engine.

My first place to look on a GE is under the running board on the suction pipe between the tank and the carbody GE installed a compression connector which used 2 rubber like compression rings. It is common for these rings to shrink and crack with age and allow air to be sucked into the fuel system. You also may want to check for high suction vacuum as perhaps there may be an obstruction in the suction line, such as a rag being sucked up into the suction pipe. We found about 20 red wiping rags in a GE unit that came off lease from a railroad that was experiencing labor management difficulties. A partially blocked pickup pipe which causes high vacuum will cause an air suction leak in a loose fitting which will work fine prior to the obstruction.

For diagnosing fuel suction problems we made a clear flexible line and replaced one of the hoses in the fuel header going to the injector pumps so we could get a visual on what was happening and then proceeded covering each fitting in the suction line with a medium coating of a thick grease, giving sufficient time between coating fittings in order to determine where the leaks actually occurred when the air bubbles were no longer visible. If memory serves me correctly the big fuel filter on the floor was under suction and when someone would over tighten the cap the gasket surface would become distorted and allow air in to the fuel system. Please let us know the outcome of your diagnosis.

Mike Tillger