2003 Toyota Sequoia approximately 216,000 miles I had began to notice a slight drop in fuel milage over the past week or so before the problem began. I drove the truck to work, in Tuscaloosa, on Sunday 30 August with no real issues except the noticed fuel economy issue and I noticed a light that appeared to me to be low wiper fluid. I went to leave on Monday morning 31 August. When I attempted to crank the truck, it would start for a half second or so and then cut off, kind of like it was starved for gas. I checked the fuel pump relay with a meter, found continuity and activation with continuity after jumping it from the battery. All fuses related to the fuel system appeared to be ok and also had continuity. My assumption was that the fuel pump had gone bad. The fuel pump, tank strainer, and fuel filter were replaced, but the problem persists. All relays and fuses that I could find related to the fuel and ignition system were checked and found to be in working order. I have checked for spark and spark was confirmed. When the key is turned on I do not here the pump priming. The tank was dropped again to be sure I had not wired the fuel pump with reverse polarity, but running direct power to the pump produces fuel from the supply side. I have looked at the wiring inside of the relay box but could not find any frayed or loose wires. A jumper wire ran between pins 3 and 5 on the COPN (?) relay causes activation of the fuel pump relay but the truck still will not run. I pulled the supply line from the fuel filter and jumped the pins mentioned and I get a good flow of fuel. Pulled a return line after reconnecting the fuel filter, and also get a flow of fuel from it Used a code reader but no codes are stored in the computer.
