Injector pump problems

[4bt power]

OK so here's what's happening. My 7.3 IDI turbo rpm wonder's at idle and is really jerky at low rpm like 800 to 1900 rpm range but when I unplug the back wire on the IP it stops and runs fine. So what's that wire do?


PS. It's a 1982 f100 with a 7.3 IDI turbo with zf5 speed and 2.75 rear

 

[Thewespaul]

Welcome to the forum, the rear prong activates the cold advance solenoid. This solenoid moves a check ball out of the return fitting and drops housing pressure to aid in cold starts and to advance timing. If the pump is not getting solid fuel pressure and the cold advance is on often times people experience the surging/bucking/snappiness you are describing. The solenoid is really not a critical item for the operation of the truck so you would be fine doing without it. I’d recommend replacing the fuel filter and running some hotshot’s diesel extreme through the whole system to help clean it up.

 

[4bt power]

OK thanks for the reply.


Trust me it's not fun when you're going 50mph. And it does that the tires actually spin