A friend of mine has a 96' 3500 2wd, 5 speed with something like 260,000 mi. Recently he has noticed a significant loss in power. Someone told him it was most likely the fuel transfer "switch". I ask if they meant the fuel tranfer (lift) pump and he was not too sure. Any idea where I should start diagnosing his problem? This friend came to me a year ago with the same issues he has now and I adjusted his valvetrain for him and that solved the problem at the time. I don't believe he's logged enough miles for another valve adjustment yet. Any ideas would be greatly appreciated!!!

 

what characteristics come with the powerloss. is there white smoke? if so, retarded timing, advancing it will help along with adding a pinch of power as well. another thing is making sure the fuel filter isn't plugged, or the air filter. restriction on either one will cause loss of power. if he still has full exhaust, the catalytic converter may be plugged as well. the fuel solenoid, might be out of adjustment(it might not be lifting up all the way, restricting fuel flow) the overflow valve on the exit side of the injection pump may be worn out letting the fuel pressure drop(also a loss of power, they are a cheap fix) i doubt the lift pump is bad(they rarely fail but you can check the pressure on from the banjo bolt on top of the fuel filter housing. we might be able to narrow it down if you can give a few more characteristics of the "loss of power", let us now.

 

That's pretty much everything to check I can't think of anything.

 

the fuel heater strainer is probably gummed up if its never been cleaned or replaced it also probaly needs new fuel lines. Any of the things in the other post as well as this stuff would cause a power loss.

 

Thanks for the input I'll have him bring it by and take a closer look and get back to y'all when I know more.