[ST] Fuel leak

[Steve Lawler <slawler@xxxxxxxxxxx>]

For a while now I have had a slow fuel leak. I could smell it and my 
mileage had dropped from about 190+ miles per tank to about 175 miles. 
The problem showed up a month after I had the fuel fittings replaced 
under the recall. I thought that it might be the cheesy new ones so I 
replaced them with the better steel ones from Team Triumph. That didn't 
solve it. I had removed the tank several times in an attempt to find the 
problem. But could never isolate it.

During my 24,000 mile service I explained the situation to the shop 
manager. They couldn't find anything. The tech told me that my exhaust 
valve shim clearance was too tight and that I might have been smelling 
unburned fuel and that would also explain the decrease in mileage. One 
tankful later and I knew that wasn't the case.

I suspected the fuel pump gasket so I replaced it. I was careful to not 
over-torque the screws as I knew that this was a problem from earlier 
posts. The problem continued. Next I gave every bit in the fuel system a 
good wipe down and went through a few tankfuls. Saturday I removed the 
tank for the umpteenth time this year and closely inspected everything. 
EUREKA! I found crud built up around the fuel pump gasket! I removed the 
pump plate and looked at the gasket. It was fine. I checked the surface 
of the tank and discovered that the areas between the threaded inserts 
were significantly lower than the holes with the threaded inserts. 
Hmmmm. Some of the inserts wee closer to the surface than others. I 
surmised that some monkey had over-torqued the screws and caused this.

I drained the tank and grabbed a small block and some 150 grit sandpaper 
and slowly went to work. After quite some time I started to sand the 
inserts while there were still areas between them that were untouched. 
Between moments of clarity and annoyance I decided to remove the fuel 
sender and look at the inserts there. The gasket was the same type, the 
inserts were well below the surface of the plastic and the areas between 
were depressed. I knew that I had to do something about the raised 
inserts. After trying to gently push one back in I knew it meant surgery.

My Dremel tool was locked safely in the shop at work and going to get it 
would mean over US$10 in gas and tolls. Instead I drove to Sears and 
bought some bits and "borrowed" a Dremel tool.

Back in my driveway, I prepped the patient for surgery. I removed the 
tank cap, irrigated the tank with water followed by a healthy dose of 
compressed air to remove any fumes that might get ignited by a spark, 
propped it up on a furniture blanket and an empty 5 gallon bucket and 
started gingerly grinding away. I used a tungsten ball to remove most of 
the meat and then leveled off the areas with the flat end of a 
cylindrical "diamond point" bit. Only 5 of the 14 inserts needed the 
procedure. Afterwards, I sanded the the surface smooth with some 400 
grit wet-or-dry sandpaper. Irrigated and blasted the patient. Wiped 
where I could reach with paper towels and set it in the sun to dry. I 
closed up the patient and reassembled everything. I should know by the 
end of the week if the operation was a success or not. I'll let everyone 
know.

While waiting for the tank to dry I got bored so I removed the end cap 
on the fuel sender and made an interesting discovery. Inside the tube is 
a float with a small magnet that travels along a printed circuit with 
several magnetic reed switches sealed in glass and several resistors. As 
the float goes up and down it closes different switches and the change 
in impedance tells the gauge where to point. I actually thought that 
that was quite clever.

The other thing I did while waiting for the tank to recover in post-op 
was write on the fuel pump plate in huge letters "6Nm" twice. Once 
upside down.

I will also be writing a letter to the dealership to let them know how 
unhappy I have been lately.

--
Steve Lawler
Verona, NJ, USA

2001 Sprint ST "Blue Devil"

"Mit der Dummheit kämpfen Götter selbst vergebens." (Against stupidity 
the gods themselves contend in vain.)
            -- Friedrich von Schiller
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