Not a problem. I had to duck out for a few minutes to help my wife.

The style of Bosch lift pump that you have is by far one of the most common. It is a service able lift pump and can be easily tested.

First of all one of the common problems with these pumps is the hand primer. If you notice that the hand primer leaks fuel when pumping then there is a good chance that it sucks air when the mechanical pump is operating preventing good fuel flow. If you remove the suction line from the pump and crank the engine with your finger over the inlet you should quickly feel suction on your finger. If you do not notice suction then there is an internal problem.

The pump has three main components for pumping, the two check valves #4 in the diagram and the main pumping plunger under the #7 cap. When the check valves fail it becomes difficult for the pump to hold suction and often you will experience fuel bleed back issues. If the main pumping plunger fails then it is most often due to it seizing in the bore.

The two check valves can be removed and inspected for wear or damage. If the check valves have circles worn in them or chips (they are ceramic) then they should be replaced.

You can remove the #7 cap and disassemble the pumping plunger. Inspect the plunger and housing for scoring. If you find the pumping plunger seized in place or very scored the whole pump should be replaced.

If this has completely answered your question please hit the green "Accept" button so I get paid for helping you. If you need further assistance simply reply to this message and I will do my best to help you out.

Thanks,

Kevin