While trying to help a good friend of mine who’s ’02 Chevy Suburban had broke down on him and thinking it was a fuel pump, we finally decided to take a look at it to test it to see if it was electrical or the in-tank fuel pump.
The first part of troubleshooting an electrical system is you check fuses or relays first as they are the weak point that controls most of a cars electrical system. So we accessed the fuse box first. The fuses turned out good so then we tested the fuel pump relay and to test the relay is a two-person job when it comes to the fuel pump.
One person has to be holding the relay as the relay is just barely touching the contacts in the fuse box as the other person is turning the ignition switch over. While the one is holding the relay, you will hear a light clicking and feel the clicking as the relay is doing its job properly. If it’s not doing this your relay may be the problem.
We discovered that it was NOT the problem. Then we decided to down the harness to the fuel pump connection which we had unplugged from the tank without lowering the tank. We found we had had the power there and this was a good sign. At this point, we knew it had to be the fuel pump. So we decided to go to the parts store where he had bought the last one. Lucky for him it was still under warranty. My friend had a unique idea of not dropping the tank to replace it. Instead, we would cut a hole in the floor above the fuel pump in the tank to make access to this fuel pump much easier for any other times if this ever has to be done again in the future.
So we had to remove the backseat and that took six nuts to remove the seat and we had to remove some plastic moldings on the passenger side. And wow! How much room we had after taking the seat out. Now, all we have to do is cut into the rubber flooring and the insulation for sound deadening and then we measure about where the fuel pump is located underneath so we don’t cut too big of a hole we can’t patch after we’re finished.
Now when we planned to cut this hole out we used a drill bit in four corners for starter holes, then we used a metal cutting bit on a jigsaw as neither one of these tools will cause a spark and won’t go in to deep to hit the tank or the frame or our fuel lines and would do the job efficiently. When using a jigsaw be patient don’t rush it and try to keep the jigsaw as straight as you can and not to bend your blade.
This was tedious because we were working around a gas tank and I am always a little scared when working around flammable products. For extra precaution, we moved our cars away from the Suburban. When we finally got to the fuel tank and the pump, we got a long flat bit screwdriver and a hammer to release the ring lock to release the fuel pump from the tank. Then we removed our lines and they were damn determined with our line disconnection tools that they did NOT want to come off! So we unplugged our electrical connection. Once we changed out the fuel pump and everything was reconnected our Suburban still refused to start. Now the new pump came with a new wire connection to tap into the Suburbans harness. Once this was done we connected it to our fuel pump. But still, it wouldn’t work. Then we thought, with the old fuel pump connection we added some primary wire to it and connected the positive and ground wire to a spare battery then hooked our reconnected our connection to our new pump in the tank, then we tried to start the Suburban. After a couple turns of the starter she started right up.
Then we shut her off. At that point, we knew she had fuel in the lines and the engine itself so we reconnected the harness and fuel pump connection back into the new fuel pump and tried to restart the Suburban again, and this time was a NO GO. Then we knew at this point there was another electrical problem existing. So we put our heads together to diagnose where it could be.
We looked at the harness from the pump forward, but be didn’t have to go too far from the tank. Only about 12 to 18 inches forward and found about 2 wires completely fried. And THERE was our culprit! When I first tested the wires in the initial electrical problem my connection I was testing from the fuel pump, my friend had taken it off and it was hanging over the left side of the frame by the left rear door. At that point where the burnt wire was actually showing me power because at that point it was actually making a connection.
Then once up top in its normal position, it wasn’t. We should have tested it once again before removing the existing fuel pump in the tank before the hassle of removing the pump. But at least now we have a hole in the floorboard for easy access to the fuel pump for any other fuel pump repairs in the future. Having this hole was a brilliant idea from my Buddy. He will be going with marine type application for a door to close the hole off so we may never have to drop the tank for the fuel pump or electrical repairs in the future.