Hello,
I'm in the middle of my dual fuel pump replacement on my newly acquired 99 XJR The pumps don't match my stock connectors (close but no cigar) and I need to splice on new connectors. The pumps came with crimp splice connector which are probably fine but I was going to solder and heat stink the new connectors. I always hate to trust those crimps. Does anyone know if heat shrink tubing does OK submerged in gas? Thanks.
Doug

 

There is heat shrink tubing made for submersing in gas and chemicals

 

Thanks for the tip on heat stink. I found a slew of recs on the web after I started looking into the subject and have some fuel resistant material coming from McMaster-Carr. I was looking over the wires to make sure I knew which way they needed to be hooked up and noticed both harnesses from the evap flange to the pumps are the same (except for the blue or white connector at the flange. Any idea why the colors are different? Also one harness was wire tied to a fuel hose below the "black box" in the middle of the harness, I thought I'd find that one was longer but they're the same length. Should they both be tie wrapped below the box? Does anyone know what the black boxes are? My schematic doesn't seem to mention them. One thing I did think was peculiar is one of the white wires was off white. I'm not sure if that's a sign of over heating or just one part aging a little differently from its neighbor. I'm making a little more out of this job than I need to I know but it hasn't been fun (especially disconnecting the pipes under the car) so I'd like to only do this once. When the car showed up I had a code regarding a bad fuel pump relay and found a jumper (not stock & very light wire) connecting the grounds of both relays to a chassis ground point. The car wouldn't run without the jumper so I put it back but I'll have to look at the trunk mounted fuse box next. Are these weak points as well?

 

Overheating of the wiring is a known problem.

The "black box" is a noise suppression device you can well do without.

 

Plums, I was suspicious that the black box was for noise. I'm wondering now about the overheating issue as adding a splice isn't going to help the wire pass current. Is there a solution other than just replacing the harness with heavier wire? I can redo the whole harness and delete the boxes but I wonder if that's just allowing another part of the system to see to many amps...

 

The overheating is normally at the connection to the plate at the top, so the
splice further along the wire is not going to hurt.

I have a pet theory that it is the black box itself that induces the overheat.

 

Plums, that's a good point with 4 connections, minimum in the box they can't help. If the materials are at all close to their design limit for current carrying they'd easily affect things. The funny part about my harness (the off white one) is that the whole white wire looks discolored. The harness connection to one of my pumps was pretty easy to disconnect so the loose connection would look like extra resistance to a current carrying part and allow it to heat up. Fortunately the wires at the flange look good so this might just be a discolored wire (insulation) issue.

 

A good crimper will produce extremely secure connections, better than a soldered one, as soldering makes the connection brittle and the joint can fatigue fracture.

Most people's impression of crimped connections results from the use of poor quality tools.

The best way to connect two wires is with a heat shrink crimp butt connector, like this :

ANCOR MARINE Heat Shrink Butt Connectors | West Marine

 

Mr SF,
I agree about the poor quality crimps from poor quality tools. I think I have a pretty pedestrian, all in one crimper in my tool box so I only use it for connections I can get at easily or don't really consider essential.
I think a heat stinked and tie wrapped solder connection should be pretty safe from fatigue and although I've heard just what you mentioned about brittle joints haven't had any trouble with a solder splice myself.
What would be good to know though, along with the west marine connectors is what tool would give a secure crimp connection that wouldn't over stress the plastic or metal of the connector. Usually when I get a nice crimp that doesn't damage anything the wire pulls out the back on my check. Then I proceed to crank down.
If you've got a recommendation pass it along, I'm always looking for something to add to my tool box!

 

I got home from work and found my fuel resistant heat stink waiting for me on the front porch. I enlisted my son's help holding the wires while I soldered and had the pumps wired up and the tank in the car before supper. Everything looks to be leak free and the restricted performance message is gone.
I can't seem to erase the codes with my reader and am wondering if it's something to do with needing to go thru a certain number of key on-off cycles before they'll clear. I was actually surprised to see the restricted performance message gone but I've never been one to look a gift horse in the mouth.
Now my attention goes to the none too gracefully installed jumper that runs from one fuel pump relay ground to the next fuel pump relay ground and over to the bolt holding the fuse box to the trunk floor (ground). I'm not sure why one of the previous owners decided this was the fix his (or her) cat required but it won't run without it and I won't be happy until my fuse box looks stock.
Any thoughts would be appreciated as would any recs for a quality crimping tool (mfg & source) for simple butt splices. Soldering's fine but as MR SF pointed out not foolproof.
Thanks again for the help.
Doug