How To Not Burn Your Fuel Pump on Your Tow Rig

This article covers one of the most important things that are a lot of times over looked.  The tow rig, we get all wrapped up in getting the boat or travel trailer ready for the trip we sometimes neglect the tow rig. Then tragedy hits and the truck breaks down and you have to get the truck towed into the dealer ship on a Friday only to be told that your fuel pump is bad and 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 is 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 pissed off 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 night mare 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 are going to address that.

But first let’s get into how an electric fuel pump works. The fuel pump is basically electric motor that runs on 12 volts on the bottom of the pump it has gears, or impellers if you will, housed in the pump. 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. When you turn on the ignition there is a reference signal from the E.C.M.  that is sent to the fuel pump for about 5 seconds and pressurizes the fuel system. When you go to crank the engine it energizes the fuel pump again but also the ECM is opening and closing 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 E.C.M. is getting 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.

                Your engine comes to life now you have full fuel system fuel pressure going to your fuel rails that your injectors are plumbed into. Rule of thumb and it varies from manufacture to manufacture but about 35 PSI. The fuel it continually flowing through the fuel rails to the injectors and the E.C.M. controls the pulses on the injectors what fuel is not used by the engine is plumbed back through on a return line off the fuel rail back to the tank, it’s a continual process that happens over and over 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 wears on and the miles start climbing on the truck more and more fuel is introduced into the tank that has water, dirt and rust in the fuel. If you use the truck for commuting for work during the winter with stop and start traffic a lot more condensation and contaminates are introduced into the tank and fuel system.

                Then the fuel filter starts plugging up with contaminates and and gets to the point it can no longer filter the fuel coming coming through. Now the fuel pump is straining and working harder to pump the fuel through the filter to your injectors. It is like making a tight fist and covering your mouth and trying to blow through your fist, it’s going to be very difficult to push air through.  It is the same concept on a fuel pump.  Not only is the pump straining to keep up with the demands of the engine but now those contaminants are by passing the fuel filter going up into the fuel rail and into the injectors. The injectors are very a precision device 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 plugging up then they stop misting from the plugged ports to dribbling into the combustion chamber. Now your performance suffers and your fuel mileage goes way down. Also the those dribbles cause an over rich condition and the excessive fuel is introduced into the catalytic converter through your exhaust system  and it will start plugging it up and 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 the fuel pump it works so hard to get the fuel to the engine it will just give out and short out from being over burdened with back pressure. Another mistake people make is they think it’s ok to run the tank dry or close to dry before filling 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 no longer will 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 the ruined vacation.

                But 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 have to either have all the injectors replaced or flushed if the injectors will flush, and now you also have plugged catalytic converters  and more than likely damaged O 2 sensors.  Now you are going to have to really dig deep with the possible injector replacement and Cats now a fuel pump and fuel filters you are probably going to have to cough up close to $5,000.00 to $7,000.00 or more in repair bills. Needless to say it will be a long time before you will ever have the money to go on another vacation.  Once you pay for all the repairs plus Hotel and meals now you’re close to 10 grand! Ouch! This was one expensive vacation. 

So 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 don’t let it run bellow a quarter of a tank if at all possible. There will be times you are on a long trip and you have no choice but don’t make a habit of it. My Mom told me something that my Grand Pa said a long time ago: It doesn’t cost anymore to keep the top half full than the bottom half. Grand Pa was a smart man. When I go on a trip with my truck and trailer I try and keep them topped off. You will thank me when you are out on one of those long stretches of road late at night and the nearest gas station is 200 miles away and you are getting 7 to 8 mpg towing a heavy boat or RV.

• 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 also clean out your combustion chambers.

• The most detrimental thing you can do to an engine and fuel system is excessive slow driving in traffic stop and start and driving very slowly especially during the cold winters months. About once a week find a  highway with very little traffic , do this on a Sunday if you are in a City and get on a on ramp check to make sure you are clear , no traffic approaching and punch it on to the freeway . You will see a bunch of black soot come out the exhaust. Don’t worry that is what you want you are not only cleaning out the combustions chambers you are blowing out the cats and exhaust system and the ejectors .  Do this a few times during the day when possible until you no longer see soot coming out.  You will be surprised how much power and more smoother and engine runs when you clean it out. Dump some fuel system cleaner in first then fill it with high quality fuel to mix up the fuel system cleaner and take the rig out on a long trip and blow it out, that is the best thing to do. Throw the kids and wife in and go on a drive and have a picnic. Call it a blow her out trip. You will love the improved performance and fuel mileage. I recommend Sea Foam fuel system additive but you can use any good quality fuels system cleaner.  Follow the manufactures instructions on the bottle.

• Keep your engine tuned to manufactures specs and always check your air filter when it gets dirty replace it.

If you do 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