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How To Not Burn Your Fuel Pump on Your Tow Rig
We often get so wrapped up in getting the boat or travel trailer ready for the trip that we neglect the tow rig. Then tragedy hits, and the truck breaks down. You have to get the truck towed into the dealership on a Friday only to be told that your fuel pump is bad, they don’t have it in stock, and your truck won’t be done for another week.
They also inform you that the pump and installation are going to be close to $1,500.00! So you have to drag the kids and family to a hotel and get ready to hunker down for a week full of expenses and angry kids and a wife to boot.
Not only that, you have to call the boss and tell him you can’t make it to work next week. That dream vacation now has turned into a nightmare that is going to cost you thousands of dollars. And now you don’t even know if you are going to have a job when you get back home.
Could things have been prevented to save the fuel pump from premature failure or prolong the life expectancy? We're going to address that.
First, let’s explain how an electric fuel pump works. The fuel pump is basically an electric motor that runs on 12 volts. On the bottom of the pump, it has gears, or impellers, housed in it.
There is also an inlet screen that snaps on the bottom of the pump to pre-screen the contaminants in the fuel from getting into the pump and plugging it up and burning up your pump. Without the screen, the pump would not last long and would fail in a very short time.
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When you turn on the ignition, there is a reference signal from the ECM that gets sent to the fuel pump for about five seconds to pressurize the fuel system. When you go to crank the engine, it energizes the fuel pump. The ECM opens and closes the injectors to let the fuel into the combustion chamber at the right time for each cylinder. These are called injector pulses.
When the engine fires and the ECM gets the signals from the sensors, it sends the signal to the fuel pump to stay energized when you release the ignition from start mode to ignition.
Now that you have full fuel system fuel pressure going to the fuel rails that your injectors are plumbed into, your engine comes to life. The fuel is continually flowing through the fuel rails to the injectors. The ECM controls the pulses on the injectors.
The fuel not used by the engine is plumbed back through on a return line off the fuel rail back to the tank. This continual process happens repeatedly while you are driving.
When the truck was new, the filter was clean, the pump was new and the injectors were clean. Everything was performing as it should, but as time wore on and the miles started climbing on the truck, more fuel was introduced into the tank that had water, dirt and rust in it.
If you use the truck for commuting to work during the winter with stop-and-start traffic, more condensation and contaminants are introduced into the tank and fuel system.
Next, the fuel filter starts clogging up with contaminants and eventually can no longer filter the fuel coming through. At this point, the fuel pump strains and works harder to pump the fuel through the filter to your injectors.
It's like making a tight fist, covering your mouth and trying to blow through your fist. It’s going to be very difficult to push air through. It's the same concept as a fuel pump. Not only is the pump straining to keep up with the engine's demands, but now those contaminants are bypassing the fuel filter and going up into the fuel rail and into the injectors.
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The injectors are very precise devices and have very tiny holes in them that spray out a mist. The mist is what you want to get 100% performance from your engine. When the injectors start clogging, whether from rust, saltwater or other contaminants, they stop misting from the plugged ports to dribbling into the combustion chamber.
Now, your performance suffers, and your fuel mileage goes way down. The dribbles cause an over-rich condition, and the excessive fuel is introduced into the catalytic converter through your exhaust system, where it will start plugging up. Then, your performance and fuel mileage will really suffer.
Eventually, if your rig does not get the fuel filter serviced, the injectors will plug up, and now you won’t get fuel to the cylinders, and you will have misfires. The next thing to go will be the fuel pump. It works so hard to get the fuel to the engine that it will just give out and short out from being overburdened with back pressure.
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Another mistake people make is they think it’s ok to run the tank dry or close to dry before filling it up again. The pump is cooled by fuel. As long as there is sufficient fuel in the tank that covers the fuel pump then it will get the proper cooling it needs.
Once the fuel level is below the pump, the pump is exposed and will no longer cool. This is detrimental to a fuel pump and will cause premature failure. This is when the truck breaks down and will no longer run, and we get back to that ruined vacation.
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Now, things are a lot worse because you didn’t have the rig serviced. You not only have to have the pump replaced, but you also have to either have all the injectors replaced or flushed if the injectors will flush. You also have plugged catalytic converters and, more than likely, damaged O2 sensors.
You're going to have to really dig deep with the possible injector replacement, catalytic converters, a fuel pump and fuel filters. You're probably going to have to cough up close to $5,000.00 to $7,000.00 or more in repair bills.
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What could have been done to prevent premature failure of the fuel pump, injectors and cats? Let’s dive into that right now.
- Keep fuel in your tank at all times. Don’t run it dry, and if possible, don’t let it run below a quarter of a tank.
- Have your fuel filters changed at regular intervals. I recommend every 12,000 miles.
- Run injector cleaner at least every 2000 miles. This will keep your fuel system clean and clean out your combustion chambers.
- The most detrimental thing you can do to an engine and fuel system is to drive excessively slow in traffic, drive in stop-and-start patterns and drive very slowly, especially during the cold winter months.
- Keep your engine tuned to the manufacturer's specs. Always check your air filter. When it gets dirty, replace it.
If you follow these important steps on a regular basis, you will have years of trouble-free miles and, most importantly, more time with the family to make fond memories.
Roger Hockemier
Performance Tech