This is probably my first post here. Been a long time reader. I have an 85 cat D6d with 3306 and the sleeve metering style injection pump with pencil nozzles. The pump will not stay primed. I can get the machine to run by priming the hand pump and it clears out and runs fine eventually. I have installed a new hand primer pump. I also recently pulled the governor off the back of the pump and rebuilt it due to a small leak. Fuel seems to be bleeding back from the transfer pump through the return line. I hav no external fuel leaks currently and no fuel in the engine oil.I see there is a bypass and a check valve in the main portion of the pump and was wondering about replacing those but I’m at a point where I’m about ready to pull the whole pump and take it to be rebuilt. Any suggestions would be appreciated
Did you purchase an aftermarket hand primer pump? Or, genuine Caterpillar?
The constant bleed valve and or siphon break on the top of the fuel filter housing could be causing you grief. Take them apart and clean them. Make sure the disc in the siphon break is free to move around.
Ok thanks. It is an aftermarket hand primer
I’ve had problems with the aftermarket primer pumps bad out of the box. I’ve never installed them, but my customers do. Then, they pay me to troubleshoot.
could be air leaking in a bad gear pump seal