Smell Fuel?

 By Brandon Baldwin

I’m doing this one a little different.  This time I’m making this column related to one of the jobs I’m working on right now.  The 2003 Trailblazer’s first complaint was that it had a hard start.  This particular hard start was that it simply took longer to start than normal.  Then, the driver said that he thought he smelled gas.  Finally, he saw some dripping occur from the frame near the driver’s door.  Yes, it was fuel.  This is dangerous.  If someone was to drop a cigarette near the vehicle, since he commonly parked in public parking lots, the TB would start on fire and may even cause fire for other cars or structures nearby.  If you smell gas, or something like gas around your car, or someone else’s.  Do something about it ASAP. 

In this situation, the Trailblazer fuel leak required that I lower the tank to locate the exact leak.  The only metal part left to the fuel system was the sending unit.  The elbow coming out of the sending unit for the  pressure  side  of  the  fuel  supply  had  rusted  thin.  Therefore, it only leaked when the pump was running.  The fuel would drip down the lines, down the tank to the tank support strap which holds the tank to the bottom of the truck. 

The fix requires replacement of the sending unit, and the hold down ring.  I say the hold down ring too, because, the hold down ring often distorts or breaks due to rust.  I tried to get new parts in the area, but the local parts stores were out of stock on everything needed.  Must be popular.  It will soak for a few days in penetrating oil while we wait for the new parts to come in.  Do NOT use a drop light around any of this  while you  are  working  on  or  around  fuel.  The  drop  light  is  a  source  of ignition.  Use a flashlight instead.  I know of 2 shops around Buffalo who used a drop light.  Both resulted in a fire.  One burned the shop down, the other burned a hole through the roof.

The other source of fuel  smell  can  be  rich exhaust.  Many people mistake a rich exhaust smell for fuel fumes.  If you don’t know what rich exhaust is, it’s exhaust  that has a little too much fuel left over after having gone through  the  engine’s  combustion chambers.  Current vehicles have a catalytic converter to run the  rich  exhaust  through  which  takes any left over oxygen and combines it with any left over hydrocarbon (fuel) in the  exhaust.  You  might  think  that  you will always hear an exhaust leak, but you won’t.  If you are able to smell the exhaust  in the car,  there  is  a leak before the tailpipe.  If you smell exhaust, there is the threat that you may be breathing carbon monoxide, which is colorless and odorless.  It will be with the rich smelling exhaust that you can smell.  This is life threatening as well.  (Even if you weren’t concerned for you life,  the oxygen sensors will read the oxygen pulled in the exhaust leakage hole between exhaust pulses.  This  will  make the computer add more fuel to compensate for the oxygen, so you fuel mileage decrease.)  Replace the exhaust, or the bolts that have broken on the exhaust.  

Both  these  situations  need  to  be  taken care of ASAP.  Like I said, this one is a little different, but I thought we had better address this as it can be dangerous, and I just happen to run into both recently.  

Good luck.  Ž

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