Discussion Starter · #1 ·
I have a 1988 isuzu pickup, 2.3 liter, carbureted, 4ZD1 engine. Recently got this truck and was looking it over; found the mechanical fuel pump under the intake manifold, it was not easy to see but noticed one of the "outlets" on the pump is not connected to anything. No one seems to know what this is for, except to suggest it is some sort of vent. If it is supposed to be connected to something I would like to make sure I do that, so thought you folks might be able to help. Otherwise, truck runs great, gets 22 mpg city - don't know if that is good or bad for the model. So if anyone has any info. I would sure appreciate the help.