if the fuel pump does not go off after 5 seconds, koeo will the fuel pressure go to 75lbs?
8 Answers
make sure that the black wire with a pink stripe at the fuel pump driver module is not contacting the car frame. use a multimeter set to ohms. if the black and pink wire does contact the car frame the fuel pump will come on with the koeo, and stay on and not go off . this will cause fuel pressure to be high, 255lbs on the code reader. 255 lbs will cause a code to be sent, p0191. the real pressure is 75 lbs, at the fuel filter, even though the code reader says 255 lbs. if you remove the black and pink wire from the car frame the code reader will say that the pressure is 127lbs, this is the correct pressure reading from the code reader. at this point the code p0191 can be cleared from the pcm and no codes should be present. this information cost me three ford manuals. one month of reading ,manuals and internet. around $500.00 in new parts for my 2003 ford taurus. you are welcome :) sadot.... :)
the black wire with a pink stripe is the output from the fuel pump driver module pin number 3 to the fuel pump. the fuel pump driver module grounds this wire to turn the fuel pump on . page 24-7 fpdm 9h307 574 / 16 BK / PK PIN 3 OUTPUT NEG. FPDM CONTROLED, TO TURN ON FUEL PUMP
I have the same problem with my daughters car. I removed the rear seat and accessed the black/pink wire. I pulled apart the harness from the fuel pump driver module to the wires at the top of the tank. The wire was not grounded. I cut the wire at the fuel pump driver module and the pump still ran. I can only assume that the fuel pump is getting a ground internally inside the tank. Anybody ever hear this one? Its happened twice. p0191- I check it out and then it goes away for awhile.
Under the car ,passenger side is a connecter that is connected to the fuel pump. At the rear of the car ,under the rear seat /or at the right rear of the trunk. Any way,Jack up the Car .block the wheels and put the parking brake on. After Jack ing Cking up the car. Put support under the car so you can work safely under the car. You will find the pink /black wire from the pump. Has been cut and grounded. Take the ground wire Off and solder and wrap with electric tape. Reconnect battery. And you should no po191 And o The pump should go off after 5 seconds ....good luck. Sadot :) the pump
Thanks for your response. As I stated I my previous response I removed the rear seat and fuel pump driver module. Lowered the fuel tank and separated the harness from the top of the tank to the fpdm. The blk/pink wire was not grounded anywhere. With the koeo I cut the blk/pink wire at the fpdm The pump still ran. The only possible explanation is the wire is grounding inside the fuel tank. Has anyone ever come across this before. My background is 28 years as an ASE Master tech. I have never seen anything like this before.
The last time the pink/black wire was next to gas tank under car. Your statment said you dropped the gas tank and checked for a wire under car. It is possible but not likely that the computer has a hard ground. The ground is at the rear of the car I think. Check with ohm meter to see if pink /black wire is grounded. With battery positive disconnected ok.
Again, I thank you for your response. I want you to understand that I had this car on a lift. I had the fuel tank partially down to access the wiring. I had the rear seat top and bottom out of the vehicle. I had the fpdm unbolted from its mounting place and the wiring harness from the fpdm to the top of the fuel tank totally exposed ( all wires separated and exposed ) the blk/pink wire was not contacting the body or any other wires. Koeo the fuel pump would run constantly. While running I cut the blk/pk wire near the fpdm and the fuel pump continued running. The only possible explaination I can come up with is that the fp wiring is shorting out inside the fuel tank. I will be dropping the fuel tank and removing the fuel pump module this coming week. I will let you know what I find. Thanks again for your input. Happy New Year.
