Death, taxes, fuel pump failures

[ds99]

Hey! I did my own fuel pump for $320 U.S. And I had a 1/2 tank of fuel in it. All in my driveway and a simple floor jack with a 2x4 board to spread the weight. Does that mean the Wife has to pay me the difference?!?

[BillHarris]

Holy pocketbook, $800-$1500 for a fuel pump replacement? The part cost is bad, but the labor is highway robbery. Unless there is more involved in the newer models, I can't see much more than a couple of hours of labor in dropping the tank and popping a fuel pump in.

On the older TBI models, the fuel pump (doesn't need a "module") costs only $45 or so (aftermarket, from NAPA).

--Bill

[BillHarris]

Last week I did a pre-emptive replacement of the fuel pump on my '92, and being the inquisitive sort, I disassembled the old pump to see what was worn in it. This is a TBI "Z" engine with 215,000 miles on the clock.

Interesting design of the brushes on the motor, and I'd say that the motor fails when the brushes/commutator wears out.

The usual thought is that running the tank below 1/4 causes the motor to overheat. The motor gets a lot of cooling cooling from the gasoline being pumped through it, but I don't know how much an effect the tank level has on that ('cept for running it dry).

The first picture is of the pump and motor with the aluminum casing removed (the assembly is shown upside-down).


The second picture is of the brush holder and brushes and the pump outlet and check valve. The brushes are starting to wear at an angle, so failure is close.


This picture is of the commutator, which is axial instead of radial (first time I've seen something like this). It looks to be designed for long wear, and it looks quite worn. I'd guess that it would have failed within the next few months since there is only 0.020" of copper left before the brushes wear down to insulation.


The last picture is of the impellers of the two-stage pump. Rather neat design-- I wonder why the impeller vanes are asymmetrical?

[trybe13]

Thanks for sharing the photos Bill. My van is a 90 with just over 100k on it. Fortunately I had my fuel pump replaced just a couple of years ago when all the bad gas was going around, so I'm pretty well set on the fuel pump and hopefully won't be seeing one in person for many more years. Now I know what one looks like in the real world as opposed to just seeing them in the ads.