db2 injector pump technical question

[vincentnova]

hi everyone

i have here a 1985 cucv that Im working on.
Im trying to understand few things here any help would be appreciate . thanks

question : with the engine off and with the shut off solenoid ON to let go the fuel in :
if you send fuel via ONLY an electric lift pump , does the fuel goes all the way up to the return port/line on the top cap of the db2 ?
or does the db2 pump has to rotate at the same time to have the fuel going all the way up to the return port/line?

thanks a lot

 

[Barrman]

You can get fuel to the IP with an electric pump. But, the engine and pump have to be turning for the fuel to get to the injectors. An electric pump only helps so far. Then it comes down to battery guts and starter health.

I replaced both fuel filter hoses and the filter on one of my trucks today. I pulled the pink wire, bled the filter, installed the pink wire and fired it up. It ran for about 4 seconds and died. As I knew it was going to With the entire hose from the filter to the IP full of air. I cranked for a count of 15, walked away from the truck for a timed 3 minutes. Repeated 2 more times. Then, on the 4th cranking session I gave it about half throttle and it started to jump around finally starting a few seconds later.

That was with only a mechanical lift pump. Electric pump will cut maybe 1 of those cranking sessions out. Here is a demonstration video: