Thursday, July 24, 2008

Some days.....

This 2006 Chevy Malibu came in with a serious fuel leak from
mice chewing threw the plastic fuel line at the sending

A new pump module was installed. The FP module was a GM
unit, part number #10374394.

The job went well. Along with the FP module and some other
wiring repairs the customer also had me do a four wheel
brake job. After the car was done, a test drive confirmed
(or so I thought) everything was fine. The wiring repair
also took care of a evap code present due to the mice
chewing threw that sensors wiring.

When we dropped the tank it was half full, I did check the
gauge when it came in. We did not drain it since there was
no way too and the fuel leak had covered the underside quite
nicely. When we had the tank on the ground I swapped FP
modules, and set it back in place and plugged everything in.
The fuel was clean, and I took care not to allow any debris
to get in.

The customer picked the car up and was happy. That night he
filled it with fuel and then called me in the morning. "The
fuel gauge dropped to empty." I asked if he had filled it,
he said yes. We set up a time for him to come in and for me
to inspect my work. At first I ass-u-med it was something
with my wiring but I hadn't done any repair to the wiring on
the sending unit or it's harness, just the evap but
regardless, I thought I screwed up.

Once he arrived he had the good knowledge to tell me that
the gauge was acting in reverse, it was going from empty
towards full as he put miles on. Now I knew something was

I dropped the tank, pulled the module and could find nothing
wrong. Then I compared the two modules side by side (which I
hadn't done before) and knew what was wrong.

The one on the left is correct, the one on the right is
upside down. From the factory whoever installed the sending
unit installed it upside down, the sending unit worked, just
the wrong way! If you look closely at my terrible blurry
picture you can see the one on the left has the wires at the
bottom. The one on the right, at the top.

A new module from GM and all is well.

Some days it drives a guy to drinking......oh wait.....


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