Replacing fuel pump undertank electrical harness.

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BillB01
Posts: 40
Joined: Mon Oct 07, 2019 7:24 am
model: 907 I.E.
year: 1991
Location: USA

Replacing fuel pump undertank electrical harness.

Post by BillB01 »

My fuel pump began to not activate at times and after a lot of diagnostics verifying that the relays, pump itself and other wiring are OK, I found that the harness piece that goes to the tank has turned to stone from engine heat over the years. Are there any recommended wiring parts that work best or tricks to doing this? I see it needs a 4-wire waterproof plug, but before I order one, what have others done?
Bill
91 907ie
Buckeye, AZ.
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Derek
paso grand pooh-bah
Posts: 768
Joined: Thu Nov 03, 2011 10:13 am
model: 907 I.E.
year: 1994
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Re: Replacing fuel pump undertank electrical harness.

Post by Derek »

Later Multistrada 1000/1100 and the 749/999 series suffer from this issue where the wires break internally inside the potting compound. For these bike's there is now a replacement part available but many owners fixed them by digging out the potting material, replacing the wires and re-potting then with a fuel proof epoxy. The fuel gauge which included the gland assembly isn't listed as available on Stein Dinse's website.
If it's just the connector you are replacing that's easy. It is a 4-way Ampliversal Superseal and these are readily available.

http://www.polevolt.co.uk/acatalog/Smal ... tml#SID=54

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1994 907ie
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BillB01
Posts: 40
Joined: Mon Oct 07, 2019 7:24 am
model: 907 I.E.
year: 1991
Location: USA

Re: Replacing fuel pump undertank electrical harness.

Post by BillB01 »

The major issue for me is not the connector, but I will replace it with something like you suggest. The problem the wires from the connector up to the tank. They are right on top of the engine with nothing but a common harness sheath to protect it. Everything is brittle. So, I suppose there is nothing more to this than wiring in a new connector with some new wire to the tank inside a heat shield sheath. Tanks for the link.
Bill
91 907ie
Buckeye, AZ.
BillB01
Posts: 40
Joined: Mon Oct 07, 2019 7:24 am
model: 907 I.E.
year: 1991
Location: USA

Re: Replacing fuel pump undertank electrical harness.

Post by BillB01 »

This is the harness in question.  The sheath and the exposed wires are stiff as a board.
This is the harness in question. The sheath and the exposed wires are stiff as a board.
20200927_140507s.jpg (171.46 KiB) Viewed 5301 times
Too bad it had no heat shielding.
Too bad it had no heat shielding.
20200926_195825s.png (932.5 KiB) Viewed 5301 times
The wire colors are not all the same as shown in the color wire diagram.   All except the black ground wire change color at the 4 wire plug.  All but the ground wire have tiny plastic lettered identification labels around them.  These can be moved to the new wires.<br /><br />V --&gt; W/R  (White with Red stripe) = + 12V, label +<br />Bk --&gt; Bk = - Ground, no label<br />B ---&gt; Br =  Fuel level sensor, label W<br />Y ---&gt; Gr = Reserve fuel level sensor, label T
The wire colors are not all the same as shown in the color wire diagram. All except the black ground wire change color at the 4 wire plug. All but the ground wire have tiny plastic lettered identification labels around them. These can be moved to the new wires.

V --> W/R (White with Red stripe) = + 12V, label +
Bk --> Bk = - Ground, no label
B ---> Br = Fuel level sensor, label W
Y ---> Gr = Reserve fuel level sensor, label T
20200927_105132s.png (694.1 KiB) Viewed 5301 times
My crude revision of the color wire diagram to show the change in wire colors in this harness section
My crude revision of the color wire diagram to show the change in wire colors in this harness section
2020.09.27-21.43.png (92.67 KiB) Viewed 5301 times
Bill
91 907ie
Buckeye, AZ.
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randtcastell
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Re: Replacing fuel pump undertank electrical harness.

Post by randtcastell »

Thank you so much for your careful work and documentation.
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BillB01
Posts: 40
Joined: Mon Oct 07, 2019 7:24 am
model: 907 I.E.
year: 1991
Location: USA

Re: Replacing fuel pump undertank electrical harness.

Post by BillB01 »

I built a new harness with these parts from eBay.
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WhatsApp Image 2020-09-29 at 4.09.37 PM.jpeg (97.36 KiB) Viewed 4907 times
16 AWG GXL high temperature automotive wire in colors to match what is shown in the wiring diagram rather than what I found. So, Violet for +12V, Black for ground, Blue for fuel level sensor, Yellow for reserve fuel level.

One 4 Pin Delphi Weather Pack Sealed Connector Kit 14-18 AWG

Three 1/4" insulated male spade connectors (from my own supply)

One 4.8 mm insulated male connector (sold in pack of 20)

One insulated metallic heat shield sleeve 1/2" (sold as 3 ft strip)

I connected the other half of the Weather pack connector to the main harness. The final product worked well, but it did not solve the problem. Rechecking everything, one of the relays was not reliable I cleaned the contacts and it's good for now, although I need to replace the two FI relays.
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WhatsApp Image 2020-10-06 at 4.01.27 PM.jpeg (127.99 KiB) Viewed 4907 times
Bill
91 907ie
Buckeye, AZ.
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