I have a fass frame rail pump that has been installed for quite a while... 8 years? I have just had a no start/ no fuel pressure issue. I just replaced the lift pump relay, because the no pump issue seemed sporadic. This was not a fix. I jumper the relay harness and I can turn the pump on every time. Put relay back in, try again, walla she goes. Shut down, try again no pump. I put it to bed, tried in am, pump goes, shut down and next time no pump. Almost like it is on a timer...

Of course it is cold and rainy, and I have no dry place to work. I am planning on running a jumper wire between the 30 pole on relay and the 87 pole on the relay just to get me home (300 km drive up the Island). I don't think this could screw anything up, just need to open the hood and pull the jumper when I shut down. Any thoughts on my logic?

 

Jumper it and run it. Get home, then fix it. The only drawback to what you're thinking, is in an accident, it will keep pumping fuel until you pull the jumper wire.

This is called a field fix. Do what you have to, to get it home the safest way possible.

 

That is a fix that will get you running for sure, but what pind says is true if you get wrecked and the battery survives, so that is a risk you could probably take the odds on in your favor....

Also, I went thru two relays until I got one that actually worked for my back up lights, just a thought if you bought a cheaper one.... I hope that is all that you need!

 

If the FASS relay is not switching ON then it could be that the trigger pin is no longer receiving a signal from the ECM, or the relay is faulty. I'd seriously look at the voltage signal coming from the ECM first because if the ECM isnt sending the voltage to the fuel pump then the relay wont switch ON. But, you can still energize the relay by jumping it which could allow it to remain on as long as the switch is energized.

If you find that the ECM isnt sending any voltage signal to the relay then you can try cleaning and tightening the connections at the ECM but if the ECM simply stopped sending any fuel pump signals then you may have to wire the relay to a keyed source. Everything will be fine and work perfect except you'll loose the priming features of the fuel pump. The initial 2 second prime and the 25 second starter bump prime.

 

Thanks for the assistance so far! I made it home safe and sound, now I need to solve the problem. I did buy a Bosch relay, and it did not do the trick. When I initially tried to do some diagnosis, I put a meter on the relay harness, and found 8.5v at the switch source, which I thought was odd, figured it should be bat voltage. I wonder if between the original harness at factory pump location on up to the fass harness/ relay assembly if I have some crappy connections and have enough voltage drop to prevent the delivery pump relay from closing? How do I go about checking the output of the ECM directly? I do have a factory manual in front of me, but have not figured out exactly what I should be testing and finding. Does the ECM control the lift pump by providing ground?

 

The ECM sends 12 volts to the OEM lift pump. When the engine is cranking that voltage is transitioned on/off to reduce the overall pump pressure to about half.
The aftermarket fuel pumps pull more amps than the Carter lift pump so to remove that added stress from the ECM, pump manufactures like FASS add a relay. But if the relay isnt getting the proper 12 volts to switch the pins then they relay wont work and neither will the fuel pump.

At the engine you'll find a short wire and connector where the OEM Carter lift pump was mounted. That square connector plugs into the FASS wire loom. You can verify the voltage at that connector to assure the ECM is delivering 12 volts.

 

Thanks Katoom, I am going to give the engine a bit of a shampoo and rinse before I continue digging in to this. Thanks for the advice, will next check out put out of the factory connector.
Cheers,
Alan

 

I just recently went through this with my DDRP pump cutting out. The power wire on the lift pump harness (yellow wire with white stripe) had been worn through. Mine was just short enough and had to make a 90º turn into the connector with the OEM lift pump, putting strain on the wire. Throw in engine vibration and I am suprised it lasted as long as it did. Once I repaired the wire, everything is good again.

Here's a picture. The yellow wire (+12 Volt) had completely seperated. The damage to the black wire (ground) was me cutting it before I decided to take the picture.

 

Looks like you have a problem with vermin, not vibrations. Little buggers get up underneath there and can take a taste of random things.

 

Definitely not rodents. They would have made much more of a mess with multiple wires. The mess further up the wire you see was the Dodge factory wire tape. It's fabric based instead of vinyl like with electrical tape. I had to unravel that old tape to expose the wires, so I could splice in new wire to the connector.

Not sure why my pump wire seemed short, but it was clearly strained and bent back over the connector shell. Only happened with the OEM lift pump since it has a mounted socket for the connection. The DDRP I have has a short pigtail from the motor giving the power wire much more flexibility. Won't be a problem anymore at all either, since the new section of wire I spliced in is a few inches longer than it originally was.

 

Dodge plastic for those years was all crap. Worst is the dashes of course but even the wires were awful. My fog lights stopped working one day a bunch of years back and after almost a month of troubleshooting I found that there must have been a porous part of the insulation in a wire and it had rotted the wire on the inside without showing any sign on the outside.

I did have my FASS pump stop before too. It kept intermittently stopping and popping the fuse and I thought it was just burnt out. Turns out there is a prefilter on the fuel line before the pump that was shedding little bits of silicone sealer. The littlest ones would just kind of stutter the gears but when a little bigger piece broke loose it stopped the gears cold. I discovered this because since the warranty was out anyway there was no downside to tearing down the pump. When I pulled the top off the pump to start the teardown I immediately saw the strip of white silicone wedged in between the two gears.

If your pump was sucking little chunks AND had a section of bad wire I could see it doing exactly what the picture shows.