Thursday, April 11, 2019

What Fuels KARR's Rage...

After installing KARR's new digital gauges in 2017, the only one that we could not get to read properly was the fuel gauge.  Even after making the adjustments described in the installation instructions many times over the last year and a half, we just could not get the fuel gauge to reconcile with the tank.  This lead to me literally running out of gas twice (as in dead on the road) with the fuel gauge still reading more than five gallons.  I came to the conclusion that it had to be caused by the now 32-year-old fuel sending unit.  

I had been putting off replacing the fuel sending unit as it required dropping the fuel tank.  The fuel tank on a Fiero is in the center of the car between the seats directly underneath the center console.  The lifts at Troy's shop are center-post, so he is unable to drop the fuel tank at his shop.  This required us to raise KARR off the ground on our jack stands and wooden cribbing blocks.  We were able to get 22 inches of clearance, which provided us with ample working space.

We used four jack stands to safely and stably raise KARR.  For an added measure of safety, I used an old cinder block and another jack stand in the front of the car under the frame to catch if once of the other jack stands would fail.

We used our floor jack in the rear as a second safety measure, with the jack lightly touching the frame but with no weight on it.

Here you can see where the fuel tank is located.  It runs the entire length of the passenger compartment, right down the center of the car.  The two red jack stands in the lower corner of the picture is the front end of the car.  The fuel tank is secured with two metal straps.  The black brace that runs across the middle of the tank is the subframe connector.

The coolant lines run from the front of the car to the back, and they run along either side of the fuel tank.  In an effort to avoid damaging the lines, and to provide more clearance for removing the tank, we removed the following four brackets.

With the four brackets removed, we then removed the subframe connector.

Here is what the brackets look like removed.  They simply press the coolant lines against the frame.

The fuel lines are attached at the rear of the tank with hoses and secured with hose clamps.

I removed the hose clamps from the fuel tank filler line (large hose) and the vent line (smaller hose).  The vent line hose pulled off easily but the filler line seemed stuck.  I figured this was due to how the hose was bent within the cramped space without enough room to back it off.  I decided to leave this until the tank was dropped and then work it off.

Next I removed the clamps and hoses from the fuel feed line, return line and vapor line.  These hoses will be replaced.

We removed the two metal straps securing the fuel tank and allowed it to rest on the subframe connector (which we temporarily reinstalled to help support the weight of the tank).

We lowered the front of the tank down first and I easily slid the fuel tank filler line hose off.  The two of us were able to lower the tank to the ground, but not without spilling a little gas on the blanket in the picture below.  (Goodbye horsey blanket.  Thanks for your service.)

Fuel tank is out!  Not your normal looking fuel tank.

This is where the fuel tank was mounted.  The first picture is looking towards the rear of the car.  The second picture is looking towards the front of the car.

The bolts that secure the fuel tank are a t-shaped bolt and with a twist can be removed from the frame.  I ordered new straps, bolts, fuel sending unit and fuel pump from The Fiero Store.  I also purchased a new fuel filter and fuel line hoses from O'Reilly Auto Parts.

Next we removed the old fuel sending unit.

Comparing the old and new fuel sending units and fuel pumps.

New fuel sending unit with new pump and strainer installed.

Here is the new lock ring and seal.

Next I installed the new fuel sending unit in the tank.

New sending unit is installed with seal and lock ring secured.

I added the old line grommet/insulators to the new lines.

We used Gojo wipes to clean off the old dirt and grime from the end of the tank.  Unfortunately I do not have a before picture to show you, so picture the tank filthy grimy.  As you can see, it cleaned up nicely.

I secured the wiring harness to the fuel lines to keep it in place.

We installed the new hoses and secured them with the hose clamps.

One of the new bolts I purchased needed to be ground down.  The t-portion was too wide to fit in the rear frame bracket.  The bench grinder made easy work of this.

You can see one of the new tank straps in this picture.

The fuel tank is ready and waiting to be reinstalled. 

Fuel tank reinstalled!

KARR started up without any issues (Sara was excited when KARR did not explode).  Unfortunately it is too early to tell whether or not the new sending unit will resolve the fuel gauge issue.  There is a potentiometer on the gauge to fine tune the reading.  I will have to fill the tank a few times to make sure this is accurate, but so far it looks promising.

Two side notes:

We unfortunately did not take as many pictures during this project as we normally do.  We are both a little out of practice in documenting for the blog, but are excited to get back to the Project.

This last weekend when we installed the fuel tank it was 60+ degrees outside.  After the fuel tank project, we removed the snow tires from both our vehicles.  The joke is on us as four days later we are in the midst of a blizzard with over a foot of snow on the ground and still falling.  This snow is not helping with KARR's rage.

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