Injector Pump

[drenfroe]

How can you tell if an injector pump is going out? I have an intermitten fuel leak that is sometimes very bad, sometimes just a dribble and sometimes it does not leak at all. Mostly it just leaks. I know I need to change the PMD because my truck is stalling and hard starting and I've went through everything else, but does the injector pump "weep" when it's going out? Since it is only leaking occasionally I don't think it could be a line or o-ring. I've run my hands all around the fuel filter housing while it is leaking and it doesn't seem to be coming from there. PLEASE HELP!

[john8662]

I was about to say the fuel filter housing after my troubles with a few as of late with mine. I just smelled fuel all the time, turns out I had to go through two bad fuel heaters on the bottom (swapping in used parts, oh well). You'll need to un-bolt the housing (when the engine is cold) and run your hands all the way to the bottom of the housing, if your fingers come up wet, it's likely the housing.

Check the fuel line connection on the injection pump, GM uses spring-type quick clamps on many hoses. Also verify that the hose coming out of the injection pump (fuel return) is not broken or the connection loose.

But yes, the injection pump itself can leak, there are some panels on the pump that have gaskets that can fail. The top cover of the injection pump also has a large sealing ring that can fail and leak, causing other starting issues and issues with running due to housing pressure.

Are there any Diagnostic codes stored in the computer for the injection pump? Usually a bad PMD will not set a diagnostic code.