F0rd06

I have a 2006 F150 5.4L xlt with some starting issues. what happens is the vehicle will not start the first time and will have a drawn out crank time. then when I turn the key on a second time it will start but have sort of growl like it doesn't want too. once running though the truck runs great except I get the codes p1071 and p1074. those codes used to show up either one at a time sometimes they would never show up but not they are both showing up almost instantly after starting the vehicle. now when for in the winter time the vehicle will start no problems at all and hardly any crank time. so basically the vehicle will not start correctly in the summer but will start really good in the cold. and help would be greatly appreciated and I am new to the site and couldn't really find anything with my exact problem. thanks for any help.

Marc D

Did you mean p 0171 and p 0174? These are lean codes R&L banks. Sounds like a fuel pressure/delivery issue. Plugged fuel filter, bad fuel pump or a bad injector bleeding down the fuel pressure when you shut it off. This would account for the long cranking on startup.

F0rd06

yes I did mean those codes, but I ended up replacing one of my o2 sensors and I got one of the codes to go away. so I ruled out that problem. I have replaced the fuel filter and the fuel pump with no such luck. I also unplugged each injector one at a time with it running to see if I would hear a difference in how the motor ran, and I heard it on every injector. my hope was if it was stuck open that it would make no effect. but I guess this would be a bad test if it was just partially open. but say if it was a bad injector why was I able to start the vehicle with no problems in cold weather.

Marc D

like any engine they like to be choked when it's cold. An injector that's bad can be flooding fuel instead of the fine mist it's supposed to. Unpluging each one won't tell the real story since it will spray a small amount of fuel all the time if it's bad, power or not. The computer sends a pulse to each injector at the right time and opens it to the fuel in the rail (that is under pressure all the time). The true test of the bad injector(s) is to test the fuel pressure at the rail test port after the motor is off. You may need someone to do this since it takes special equipment. No or low pressure means it's bleeding down through one or more injectors. Fortunately new injectors are only $35 to $40 each (diesel inj. are $300 to $500 each) Try looking on a web site called Parts Train.com

F0rd06

so you think that I should just replace everyone? or is there anyway that I could possibly test them?

Marc D

You can test each one off the truck but it requires removing the fuel rail then separating the injectors one at a time, inspecting for spider cracks around the tip. If there are cracks it's bad.Next using a small bottle of gas with a hose, attach it to the top of the injector, see if it leaks. If it leaks it's bad. Then you can use a battery charger to give it 12 volts and see if it sprays or dribbles. It should spray a very fine mist. If it dribbles it's bad.
I know this sounds like a lot of work but it could save you some money. If your truck has over 150K miles chances are a full set would bet recommended anyway.
As for the testing most diesel pump repair shops can do it for you pretty cheaply

F0rd06

alright thank you for all the help I'm going to take the fuel off and do a visual inspection. if I don't see anything I just take it to a local shop and have them pressure test everything for me and I guess see where that gets me. once again thank you for all the help