fuel pump question
Thread Starter
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Freshman User
Joined: Feb 2009
Posts: 45
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fuel pump question
On these newer pumps, 2002 SD, they run for a few seconds when key is turned on and stop. Is there a pressure switch that tells it to shut off?
And the two lines that come off the fuel pump assembly, is one a return line?
And the two lines that come off the fuel pump assembly, is one a return line?
Elder User
Joined: Nov 2008
Posts: 668
Likes: 6
From: Northfield, MI
There is no pressure switch on any SD truck of that year. The pump is controlled by the PCM and is turned on with the key. On gas trucks, if the PCM doesn't see the engine cranking within two seconds, it turns the pump off until the engine is cranked. When the engine is running the pump runs continuously. Fuel pressure is controlled by the fuel pressure regulator.
The same is true for diesels, except the pump runs for 20 seconds.
And yes, there is a supply and return at the pump.
The same is true for diesels, except the pump runs for 20 seconds.
And yes, there is a supply and return at the pump.
Thread Starter
|
Freshman User
Joined: Feb 2009
Posts: 45
Likes: 0
There is no pressure switch on any SD truck of that year. The pump is controlled by the PCM and is turned on with the key. On gas trucks, if the PCM doesn't see the engine cranking within two seconds, it turns the pump off until the engine is cranked. When the engine is running the pump runs continuously. Fuel pressure is controlled by the fuel pressure regulator.
The same is true for diesels, except the pump runs for 20 seconds.
And yes, there is a supply and return at the pump.
The same is true for diesels, except the pump runs for 20 seconds.
And yes, there is a supply and return at the pump.
That's when I wondered if there was some kind of pressure switch telling the pump to start, or not to start, that could have been froze instead.
The old pump I took off spun over good when I tested it with some jumper wires, but I'm pretty sure that was the problem, maybe just getting week.
Everything is running perfect now.
