Tom's BMW R850R: Defective Fuel Pump Connector
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Broken BMW motorcycle fuel pump connector and associated parts The actual broken connector is on the upper left. I've turned the connector so that the face shown in the following photomicrographs is up (although rotated counter-clockwise about 90 degrees). The details here are much easier to see in the larger image. There are three brass connectors with copper wires soldered on to them. All three wires originally had insulation, and the entire collection of connectors was sealed inside a white plastic connector.

My guess is that the broken connector was bent and half-broken at the factory before being sealed in plastic. The plastic held the partially-broken connector nearly immobilized for 15 years, which I guess isn't too bad. Heat and cooling cycles eventually completed the break, and my fuel pump stopped working. This manifested as an intermittent fuel pump malfunction when the bike was warmed up.

Broken fuel pump and sender connector This is the normal position of the broken connector. Everything in this picture was encapsulated in plastic at the BMW factory. Here the encapsulating plastic has been carefully removed with a hand grinder, and the insulation has been stripped from two of the wires. Tracking down this problem was difficult.

Broken electrical connector A broken connector. This is a (slightly out of focus) photo micrograph of the broken face of the connector. The break is at the top of the brass connector, facing the viewer. The break occured just beyond where the connector made a 90 degree bend. This seems like a typical place for a break, although I suspect that the connector was flexed after the initial 90 degree bend was made. In other words, it got an additional bend or two after manufacture. It should have been thrown out, but the assembly line worker installed it regardless.

Close up of a broken connector. An extreme close up. Note that the upper face of the metal is several colors. I am supposing that the connector was only half intact. In this image I see a band of bright metal at the top and a band of darker metal along the bottom. Probably only one of these areas (the brighter area) was carrying all the electrical current to the fuel pump for 15 years.

Color highlighted regions on the connector. Here I have outlined the various areas in color. The yellow outlined area is what I'm guessing was intact and carrying the full current load of the fuel pump. The area in red was probably broken. The blue areas seem to be darker and may have been burned by arcing over the years. I may have things backward as far as the broken/intact areas, but it seems clear that the connector was cracked half-way through.

This means that the connector has been on the brink of failure since it was manufactured.