Another day: fuel pump died, or so I thought...
My driveway at home has a slight 10 degree upward slope. I came home from work, parked the truck as usual and went inside. Following morning when I tried starting it, motor turned over but it would not start, grrrr. I started going down the list. Spark plugs and wires are good, and plugs have a spark. I was getting P0200, P0300, P0302 and P0303 codes lately, sounds like a possible fuel delivery problem and bad 18 year old injectors. I checked the fuel pressure at the fuel rail: 5psi, 7psi when the key is on and priming! I was excited that I was able to find a busted fuel pump within a few minutes of trouble shooting.
I replaced my fuel pump 3 years ago while on a cross country road trip and paid good money at the dealer to do it, thankfully the ump came with a lifetime warranty. All I need to do now is get it out, go to the dealer and replace it. How to get it out... Do I drop the tank or do I cut a hole in the floor to easily access it? All literature I have seen makes dropping the tank sounds miserable even if you have all the tools and a couple buddies to help. But I did not want to cut my floor.
Dropping the tank by myself took 15 minutes and was one of the easiest jobs I have done in the Suburban, 3" body lift probably helped a little. 2 15mm bolts for the tank straps, 2 bolts for evap canister, 2 hose clamps for fuel fill and vent hose and 2 fuel line quick disconnects that come undone using my fingers. I didn't even use a jack, the tank slid right out.
I pulled the fuel pump out and hooked it up the the battery, it worked as it should. I ran my ohm meter and the resistance was within factory specs. Oh crap, I just dropped the tank for no reason. checked the wiring harness for the pump. One wire read 5volts, other 3 read nothing.
Wire C had 5 volts and wire B had zero volts. I found my problem the second time: power wire needs to be replaced, or the relay is bad.
I went into the fusebox and played with the relays.
I checked the fuel pump relay and it did not function properly, I switched it out with the horn relay and the horn worked as it should with what I thought was a defective fuel pump relay. I then checked the power wire running from the relay to the pump, it was good. I took the entire fuse panel apart, cleaned it and added grease on the connections, put it back together and still no power to the fuel pump.
I was stunned, all the wiring is good, fuel pump is good but no pressure at the rail and the fuel filter is two weeks old.
I decided to clean out my fuel tank to clear my mind... Drained the fuel from the 33.5 gallon tank and only got 1/2 quart of fuel from the tank. All of a sudden it hit me, I dropped the fuel tank, pulled the fuel pump, ripped apart the fuse box and fuse panel only to find out that I had no gas in the tank. And I remembered that the fuel light turned on 60 miles and 2 day prior but I was so tired at work that I forgot to fill it up.
I put everything back together, hooked everything up, put 10 gallons of gas in the tank, primed the fuel rail by running a wire from the "prime" plug int he fuse ox to the left of the fuel pump relay to the battery, turned the key, and what do you know, it fired right up and fuel pressure at the rail is 52psi.
Good times, I just spent 6 hours trying to trouble shoot my entire fuel system only to find out that I just needed gas.
Stay tuned for more shenanigans!
