Ok, I don't know what it is called, but you know, when you first turn on the key and the lift pump runs for a brief period to prime the injection pump. How long is the lift pump supposed to run? Mine is only running about a half a second, it seems to me that it used to run longer. Is there a relay to replace for this? Any help would be greatly appreciated..

 

You have to bump the starter for the pump to run and time out.

 

Not on my truck, it has always run for a bit before the starter is engaged, as soon as you turn the key on

 

Now, if you do bump the starter, the pump runs for a good 10 seconds or so, I am talking about the initial prime though

 

Mine runs for five or six seconds when I turn the key on each morning..always has. You can hear when it when it starts and when it stops.

 

Well, there is something wrong with my timer then. Where is it?

 

Actually the manual says it should run for about 1/4 of a second. Like mentioned earlier by someone, it can run for about 25 seconds when you bump the starter.

The lift pump is self priming...I didn't see anything that mentioned a primer timer.

 

Mine has always run for about 4-5 seconds at key-on but lately it may alternately run for 1 second if that, so I am interested in learning from this topic also. Still runs for 20 seconds or so at bump but I shouldn't have to prime IP that way. But I don't have an in-tank lift pump so that might make a difference.

 

Mine only runs for a split second. But fass and airdogs are programmed to run for 25 seconds after a failed start(bumping the starter)

 

The ECM controls how and when the pump will run. Two modes of operation with eng running, 1, 100% duty cycle with min 10psi except when cranking then 2, 25% duty cyc with 7psi min when cranking. When key first turned on will run for up to 2 sec, pump will run up to 25 sec when starter engaged then disengaged with eng NOT running. (starter bump)
The 25% cycle is used to limit injection pump inlet press until eng running.

 

the orginal program it would run for about 5 to 10 seconds. If it has been to the dealer and has been reflash (programed) it will now run for a 1 seconed or so.