When you think it´s the fuel pump but it isn´t quite ...

[Clemens]

My wife called me the other day that her 854 NA won´t start. It cranked, but wouldn´t fire. She said it didn´t smell like gas. So rather no fuel than no spark. I instructed her over the phone how to remove the fuel pump relay and knock onto it. Put it back in, car fired right up. I was very proud of her. On her way home she stopped somewhere. Bad mistake. Car wouldn´t start anymore. She tried jumpering the relay with a paper clip. Still didn´t do a thing. Grabbed a fuel pump relay out of one of my turbowagons and went to pick her up. Grrr, was I angry after it still had no fuel with the other relay. No pressure at the Schrader valve, I couldn´t hear the pump whining, so we had a no fuel issue. Found a contractor in a parking lot who gave me a few wires and with a bulb from the taillight I verified that I had power to the last connector of the fuel pump that was outside the tank. Didn´t want to replace the fuel pump out in the boonies so off onto the tow truck with the NA.
Orded a new fuel pump (pretty grumpy and confused because I had just replaced that one 3 years ago with a Bosch unit for over 100€).
Today I got it and just an hour later I was happy that my autoparts store let me return the pump because I could fix my old pump assembly for free. The negative wire must have had a bad connection which partially melted the connector and the insulation of the wire, thereby making everything super brittle. I just managed to leave the old wire long enough to put a new connector onto kinda solid wire and put it back together - and off the NA goes to great new adventures ...


Btw., if someone wants to reuse the plasic connector like I did - you can cut it open carefully and insert the new (or old) metal connector into it after crimping the connector to the wire. It clicks right back in, and the female connector on the pump motor keeps everthing tight together. Too bad I didn´t take a picture.

What I still don´t get is - why doesn´t the fuel short out the uninsulated wires that run in the tank? Leave alone the spark/explosion risk. I know, the theory is that there isn´t enough O² in the tank to cause an explosion - still creepy.

[abscate]

It is but it really works. The explosive limit for gasoline/petrol is quite narrow - like 2-8% by volume. A gas tank with any liquid in the tank is way, way above that.

[kranz]

What I still don´t get is - why doesn´t the fuel short out the uninsulated wires that run in the tank? Leave alone the spark/explosion risk. I know, the theory is that there isn´t enough O² in the tank to cause an explosion - still creepy.

I asked myself this same question the first time I replaced a fuel pump on a vehicle by a different Swedish manufacturer. It turns out that Gasoline is a poor conductor of electricity. So bare wires and connectors submerged in the tank are of no consequence.