Monday, May 6, 2019

Once More Unto The Breach...

The new fuel pump we recently installed when we replaced the new sending unit in KARR's fuel tank was defective.  It worked but it made a horrible constant high-pitched whine.  It was driving me crazy and made KARR unbearable to drive.  Even with my music cranked, the whine was persistent.  I did some troubleshooting with The Fiero Store where I bought the fuel pump as well as with my mechanic friend Troy.  The Fiero Store suggested the pump was just noisy and not actually defective.  Troy took one listen and agreed with me that it was a bad fuel pump.  I decided to go with my gut feeling and buy a new fuel pump.  I went with a Bosch, which was Troy's recommendation.

I also noticed KARR's starter had been hesitating lately and would not start on every try.  I decided to replace the starter when I replaced the fuel pump.

So... Sunday found us once again dropping KARR's fuel tank.  With my faithful assistant by my side I was ready to begin.

We raised KARR back up on four jack stands with the jack acting as a safety support.


We thought to measure the clearance this time.  We have almost 21 inches of clearance from the rocker panels, and 22 inches of clearance in most parts of the underbody.  There's more than enough to comfortably work underneath.

I started by disconnecting the hoses from the fuel lines.  Sara asked if there was anything else she could get me and I told her yes, a pillow for my head.  Too bad there is not one in the garage. :)  We did not use a blanket on the floor this time and instead I laid on carpet squares.

We did not take a lot of pictures of this process since we had just recently documented it.  The tank came down a lot easier this time since we had done it before and knew what to expect.

The tank had around two gallons of gas in it, so it was much lighter than the first time we dropped the fuel tank.

Once the fuel tank was down I just had to disconnect the electrical harness.  With the car in the air, this required using a step ladder and then laying over the trunk and engine bay.

Next I removed the fuel sending unit lock ring so I could remove the fuel sending unit.

I suppose this is a good time to mention that in addition to the fuel pump being noisy, I still have not been able to calibrate the fuel gauge properly.  This was the entire reason for replacing the fuel sending unit in the first place.  After watching the behavior of the gauge over the last few weeks, I was convinced the float was getting stuck on something inside the fuel tank.  I tried looking in with a flashlight first but was unable to see much.

I ended up using the inspection camera I got from my father-in-law and could see there were two plastic pieces that were cracked on the baffle inside the tank.

You can see the two broken pieces on the camera display.

Once I had secured the two broken pieces, we decided to cover the tank with a layer of Ensolite.  This sound deadening should also help quiet the fuel pump (just in case the noise was amplified from the tank being in contact with the underbody of the car).

Once we had covered the top half of the tank with Ensolite, Sara inserted the inspection camera in the fuel filler opening and watched as I raised and lowered the float while holding the sending unit in as close to its proper position as possible.  We could clearly see the float was hitting on the front of the baffle at about the 3/4 point.  This would explain the erratic readings I was getting where it seemed to get stuck at 7.5 gallons and then suddenly plummet to three gallons.  I bent the float arm back very carefully to allow it to clear the baffle.  We then repeated the procedure of using the inspection camera to watch as I raised and lowered the float.  This time it cleared fine so we reassembled and reinstalled the fuel tank.

I had disconnected the battery before removing the fuel tank but was dying to test out the fuel pump before starting on the starter, so I reconnected the battery.

Turning the ignition on, I heard the fuel pump kick on and pressurize the lines.  It was quiet!  I then disconnected the battery so I could replace the starter.

Here is the new starter.

Here is the old starter with the wire connections for reference.

Old and new starters side by side.

Another shot of the starters side by side.  You can see the shim that was removed from the old starter laying beside them.  This will need to be reinstalled with the new starter.

View of the flywheel with the starter removed.  This is very easy to get to on the Fiero.

Installing the new starter.

New starter installed.

Wires reconnected.

Dropped the fuel tank twice, installed a new fuel pump twice, and installed a new starter.  Just another day in the garage.

The last step was to lower KARR back to the ground and take him for a test drive.

I am happy to report there is NO WHINE from the new fuel pump.  The starter is working perfectly.  The fuel gauge, after being reset to full, seems to behaving much better.  I will provide an update once I have had time to thoroughly test it.

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