Fuel Pump Not Priming / Starting & Running Problems

[krista]

We are working on a solution for replacing the wiring in flanges. This is becoming very common on plastic-tank'd monsters. We're getting calls from people with < 3 years old and under 10k miles. We're trying to get the parts made in the USA and hoping I don't regret it... (I think if it was being made in China, we'd have product on shelf already)

[Blackboar19]

Chris, a replacement harness would be great.  It's a shame that Ducati does not make this part available as it is SUPER EASY to pull off one retaining clip and slide the whole harness out.

Fixed is sometimes a loose term, as it turns out, JB weld did not hold up to being submerged in gasoline.  I'm trying out a potting compound from 3M now that should do the trick, but it's not fully cured yet so I won't know for another day.

[David_wmd]

Hey I have a similar issue where sometime my bike does not start. It seems to be as if the pump is not priming. But now my main difference is that the bike has not shut off on me once running. Also sometimes if I just leave the bike and go back to it, it will fire on the first crank. Do you thinks I may have the same issue?

[iltl32]

I have this exact problem on my 620.  If you don't mind, can you answer:

How did you replace the harness on the pump?  Is this a part you ordered somewhere, or were you able to remove and re-seat it?  I'll need to run a new wire and I do NOT want to splice inside the tank, obviously.

Thanks!

[krista]

Oooo, I forgot about this thread and just was reminded of it via PMs.

Update: the Made in USA people were 5 times more costly than having the parts made in China. So they're being made in China. I'm on the 2nd sample and the oring grooves are still too deep... iteration 3 should be the charm.

For those attempting a repair:
I've suggested this to a couple mechanics: you can re-purpose wires for a temporary fix. There are normally 4 wires, (+)(-) for fuel pump and (+)(-) for the fuel level sender. You can combine the (-) leads together and then re-locate the "spare" (-) lead on both sides to work on the (+) for the pump.

Or using eyelets, ground the (-) connections to the flange itself on either side, freeing up those 2 conductors for use on the pump(+) and the fuel sender(+).

The way to construct fuel tank passthroughs is to have the wires soldered to posts in the middle of the plug. Then fill the plug with gasoline resistant epoxy. This is what eliminates the hope of a repair; the epoxy is too aggro. I suspect that the wire break is on the outside of the plug where the wires are soldered to the pins or where the wires enter into the epoxy.

To try and improve the design, I have changed a few aspects of the design... I'm basically having 1098 fuel pump wires being made and then adapt those to work in the larger openings on the Monsters.

No word about an ETA for these. Each rev takes a couple weeks then once we get everything sorted, it'll be a couple weeks for the production run. So by year's end, I'd say. It'll be in the 2013 catalog, for sure.

Thanks,
Chris

[iltl32]

Alright, I so I dug out the epoxy from the inside-the-tank side of the assembly, and 3 of the 4 wires just fell loosely out.  I'm ready to re-solder, but I have one last question: when I'm soldering, should I put the wire in the hole and then solder around the edge, or should I put some solder on the wired and then hurry up and shove it into the hole?  Or is there a third method I haven't considered?

Thanks.

[iltl32]

Also, to David:

There are a few things that could cause what you're describing.  The quickest way to test this is: when it's failing to start, check that you're getting power to the harness that goes into the tank when you turn the key.  The fuel fump power will kick on for a second and then kick back off when you turn the key to "on".  If you're getting power all the way up that point, but the pump is not priming (you should hear it fire up when you turn key to "on"), then you either have this issue or a bad fuel pump.

[krista]

Alright, I so I dug out the epoxy from the inside-the-tank side of the assembly, and 3 of the 4 wires just fell loosely out.  I'm ready to re-solder

Hmmm, I suspect that when the wires were soldered, one side got hot enough for the OTHER to melt the solder. I would tin the wire with solder first. Then heat the socket until the wire will go in and immediately remove the iron from the socket / pin.

[scaramanga]

 iltl32
when you dug out the old epoxy was it mushy or still solid?
I think whats happening is the ethanol in the fuel we buy is leaching through an incompatible epoxy that ducati uses.
when the ethanol reaches the electrical connection it eats away at the solder joint leaving it brittle and prone to cracking.
Solder is made up of a tin/lead alloy and is NOT chemically resistive to ethanol.
I think the key to a perfect repair is to make sure the epoxy we are using is truly compatible to our fuels.
I used jb weld pro and i will wait until ~January before opening it up to check how well its holding up.

chris
your soldering technique is spot on. I have an electronic background with 30yrs as a process control tech and i've always soldered using this technique. good recommendation chris

[iltl32]

I would not say it was mushy.  It was flexible, but still very firm.  Kind of like digging at a big pencil eraser.  I used a tiny drill bit and a dentist's hook to remove it all while leaving the wires intact.  I'm not sure if it's supposed to be that way or if it should be rock-solid.

Anyway, most of it is out now.  I got some J.B. Water Weld, which is supposed to fuel-resistant.  I'm going to solder everything back up on Wednesday and I'll post the results here just for the record's sake.

[scaramanga]

its supposed to be hard like the epoxy on the outside of the flange.
There is another epoxy available from Permatex, # 12020. I haven't used it but its supposed to be gasoline submersible.

[iltl32]

Re-soldered wires and re-sealed with the J-B Water Weld.  Hooked it back up (not inside the tank, just sat it on the seat) while waiting for the epoxy to dry, turned the key, and the pump primed up like it's supposed to.  Everything looks good.  Thanks to everyone for their time and help on this, I definitely would never have been able to figure it out by my newb self.