Problems with FASS pump
 

Hi, I am having fuel delivery problems on my 01 and thought I would post the question here.

I have a FASS 150 pump

The other day I started the truck and and noticed the fuel pressure gauge was reading 7.5 psi.

Didn't notice the pump pressurizing.

The truck started and ran but I did not run it for long.

The pump doesn't seem to come on when I turn on the ignition switch.

I bought a new relay and replaced it with no change.

I can jump out the FASS relay and get the pump to run.

I measured voltage at the batteries and found both at 12.2 volts standing with engine not running and sitting over night.

The alternator is puting out 13.8 volts with the engine running so it looks like batteries may be one problem

I placed a battery charger on one of the batteries and sounds like the pump will start some times but not every time.

I checked voltage at the relay and main voltage is 13.5 + with the charger running but the trigger voltage is 9 volts with the ignition switch in the on position.

Is 9 volts strong enough to trigger the relay or is there another problem?

Sounds like my batteries may need to be replaced so I will be pricing them out

Sounds like I am rambling so I will leave it at that.

Any help would be great.
Thanks, Ken

This morning I thought I would check to see if the fuel pump on the truck would trigger with the key switch.

It did so I drove the truck to work with good fuel pressure the whole trip (5 miles)

When I got to work I shut the truck off and restarted.

The pump did not trigger and fuel pressure went to 7.5.

I checked the battery voltage and it was 12.54

I may have a charging issue with the alternator because voltage should be higher. I will have to check off idle voltage