OPS switch/sensor

[mhotao]

Can my OPS switch/sensor cause my lift pump not to work? Should my overflow /fuel bleeder for my water Also always squirt fuel when truck is running. Also in what area is the OPS located on the block.

[JohnC]

Can my OPS switch/sensor cause my lift pump not to work?

Yes...


Should my overflow /fuel bleeder for my water Also always squirt fuel when truck is running.
Only when open.


Also in what area is the OPS located on the block.
Depends on the year. Earlier blocks have it at the rear of the driver's side cylinder head. Later blocks on the driver's side under the intake manifold.

[mhotao]

Thanks for info I have been told a non working lift pump can cause my PMD/FMS box to fail. I assume it is because the fuel is susspossed to help cool it. What other symptoms of a non working lift pump are there ? Thanks MHO