I have a 2001 Lightning that won't start. Cranking is not the problem. I read that the fuel pumps are suppose to prime for 2 seconds. Well, on a lucky day my pumps will prime for 2 seconds and it will start right up. However, every other day they will only prime for maybe half a second and truck will not start. I changed the Fuel pump relay, Fuel pump fuse, Fuel pump Hi/lo relay and still no 2 second prime. Me and some friends ended up sliding the bed back a foot and removing the pumps. We decided to test them and hook them to the battery and well they work. I have pumps on order but I am considering cancelling them. We put the pumps back in, connected the battery back up and what do ya know the pumps primed for 2 seconds and it started. It actually kept starting. Something is teasing me because we all cleaned up and went inside for ten minutes came back out and tried to start it and it would only prime for half a second and not start???? The only think I can think of is because we disconnected the battery and reconnected it which reset all electrical and allowed it to start. So if the pumps are good (Tested it with the battery but who knows thats straight up hotwired), relays are changed....could it be the pcm. I need help. Please someone help me. Any help would be greatly appreciated. Thanks.

 

What to look at:
1. The inertia switch above the right kick panel.
2. Measure the actual fuel pressure at the rail.
3. There is a fuel pump module involved.
4..The PCM power relay powers all these operations including the PCM, injectors, fuel pump and many other functions.
Just have to test and sort it all out.
Good luck.

 

Well, im out of things to try now. New fuel pumps are installed yet they're still only priming for half a second or so. I finished replacing all the relays and fuses. Only thing left to do is take it to a dealer unless anyone has any ideas. O and the Inertia switch...I can't depress the red button. I tried to push it in and it won't go nowheres. Does it automatically reset or do I need to try and raise it? Please help

 

Looking at the 2001 lightning wiring diagrams ther are three relays that control the fuel pumps the fuel pump relay high low fuel pump relay and also an inertia switch relay also located in the same under hood box also there is a resister located behind the bumper cover mounted with the intercooler pump. I believe this resistor is used for normal operation so if you had a coroded plug or bad resistor it may cause this problem. I would check this circuit the resistance is 7 ohms also check the ground circuit at the fuel pump. you may have a problem back there as you state that it did work after you were in that area. I had a ground problem with some Autometer guages that drove me nuts, I had grounded them with an eye on a large dash bolt at times when i turned the dash lts on the boost guage and egt would not work had to remove bolt and sand paint from mounting surface thats how touchy these grounds are. The ground for the resistor is on the drivers side of the rad support.There are two connectors that I would check for any corrosion etc. one is near the fuel tank in the center of the truck and the other one is under the hood near the relay box. GOOD LUCK

 

Thanks CHuck, It's 10:30pm now ill check into it tomorrow after I get done work. It makes sense that it would either be a resister or ground because it just gradually got worse and worse. It's probably the ground wire back by the tank. We may have moved it a little when we slid the bed back. That would explain why the pumps actually worked for bout 10 mins then stopped. Anyhow im not going to get my hopes up but ill check all that stuff out tomorrow. By the way, do you have an actual book on the lightning or are you using an F150 book? I can't find any Maintenance books for just the lightnings.

 

I have several service CD's from Ford they are a little hard to use but better than nothing. Once you get the hang of not being able to page through a book. There is a spacific section for the lightning in most of the sub topics (although the book calls it F150 sport) I was a Ford service mjr. most of my life so I still have a few connections for some left over books and info. If you need some spacifics I will be home most of the evening as far as I know, I can look up what you need and help with locations or wire colors. There are a few steps and test that you can't do because they test through the Ford scan tool, but with the wiring diagrams we can work around that it just will take a little effort. If you want to get info faster than the forums feel free to email me direct my adress is mayerchak@comcast.net I will try to help in any way I can.