got an ?
Lead Driver
Joined: Sep 2002
Posts: 9,182
Likes: 12
From: Gateway to the West
Nothing holds it. The system pressure should eventually leak down but if everything is sealed properly, it takes a day or more to reach absolute zero pressure. The pump primes the system when the key is turned to the "ON" position to compensate for any leak-down since the last time the truck was run. I am making a rather broad assumption that the truck in question is fuel injected.
Junior User
Joined: Jun 2002
Posts: 91
Likes: 0
From: Nevada
If your pressure bleeds off almost immediately, it's most likely your fuel pump. If that's the case the engine may be difficult to start after setting for awhile. I had to crank mine two to three times to start. After changing the FP everything worked fine.
Here's what I did to prove my fuel pump was bad:
1) Turn the key to 'RUN' (Don't start) Let the fuel pump run until it stops.
2) Turn key to 'OFF'
3) Repeat step 1 and 2
4) Repeat Step 1
5) Start engine.
If your FP is weak it will take a few runs to build the needed pressure.
Here's what I did to prove my fuel pump was bad:
1) Turn the key to 'RUN' (Don't start) Let the fuel pump run until it stops.
2) Turn key to 'OFF'
3) Repeat step 1 and 2
4) Repeat Step 1
5) Start engine.
If your FP is weak it will take a few runs to build the needed pressure.
Junior User
Joined: Jun 2002
Posts: 91
Likes: 0
From: Nevada
Originally Posted by dub8
could it be a bad presser reg.
