littlebuddie

Apparently code 1693 is a companion code which means that something else is going on and you will need a code reader to tell you what that might be. The on board diagnostic ignition on/off feature has limitations which will not tell you the whole story. I don't know, but you may have to take it to a dealer for complete code diagnostics. Someone on this board may chime in with better information. Is it the fact that you can't hear the FASS that you believe there is a problem or is the truck acting up in another way? I am guessing that you don't have a fuel pressure gauge.

mishkaya

Now we are getting somewhere. I am not quite sure how the FASS setup is hooked up, but I would think there would be a fuse on their harness somewhere. I would give Dan a call at FASS otherwise to explain the problem they are great guys and can help you out. I do know that the lift pump is controlled by the ECM however. You should check your grounds, and also check for codes.

lezmark7

when the engine started coughing and spluttering, the first thing I checked was the fuel pressure guage - zero. With the ignition on, I have poked into the wiring under the hood with my test light and get no power - I will call FASS - thanks for the input.

thumper549

Look at this........I have had similar problems..but in your case the ECM has to supply voltage to the L.P.(safty issue )
What I ended up doing was rerouting power from the heater / blower circuit to the VP and to the L.P so as I could at least shut it off and have it run...
There is the danger if I go up side dwn the L.P.will keep running.
You either have a open in the wire from the ECM to L.P. or a ECM with a glitch in it.
ether way I would re rout PWR rather then buy a new ECM (If your relay turns out OK )

Black sheep

I am having the same problem as lezmark7. Just wondering what you ended up doing to fix your truck or if anyone else has had the same problem.

Junk Man

On my 2000, the lift pump (airDog) always kicks to 15# with key to run and then drops to 0. Do you still have the stock fuel pressure test port? Parts store may have a FP gauge to loan. Harbor Freight sells a kit with connections to test nearly any system. Pull codes with a scanner. While you're borrowing tools, you can borrow a scanner also.

Black sheep

Found the problem the fuel pump relay was bad. The Fass Pump came with a wiring that included a fuse and relay.

Socalmat

Same problem with my Air Dog. Found the relay, thanks to your message, banged it around a little, and now it is working again. I want a new relay for the harness. Is it over the counter Napa stuff? I just called them and gave them the number on the sides of the relay, but they could not identify it over the phone.
Thanks again.
Socalmat