Hello and thank you for viewing this thread.
I am in quite the quandary with my 99 F-250 super duty.

Sometimes it runs and sometimes it doesn't. It really has a mind of its own.
When it does run,it starts beautifully and runs like a dream. When it doesn't run, it turns I to an awful crank but no start situation.
I will give you some background on the truck. As stated, it is a 99 F-250 super duty and it only has 75k miles on it. It is a very well maintained truck. I recently had the clutch rebuilt and did my own tune up. I did not have a single spark plug break in the engine thank god. I replaced the ignition coils witch set me back a hefty $350. I put all top of the like plugs and coils in. While I had the fuel rail off to replace plugs 4 and 8 i inspected the injectors and they look almost new.

What I gather is that my problem is not electrical as I have changed all relays for the fuel pump and checked the inertia switch. I have no fuses blown.I have narrowed it down to the fuel system or a faulty powertrain control module. When it does not start I can hear all the relays clicking as they are supposed to.

The reason I think it is the fuel system is because when the truck does not start I have my girlfriend turn the key over so I can listen to see if the fuel pump is priming itself. And I can't hear it at all.

Here is my issue. I believe the fuel pump is going bad on me. But once the truck starts on my I can litterally drive all around town with no issue. Wouldn't a bad fuel pump stall me out at a red light or even did while I was driving? My only other option is the powertrain control module as I have tried everything I can. No loose wires, no corroded wires. Nothing.

If anyone has advice or can steer me in the direction I need to go please help me out!
Thanks!

Nick

 

Welcome to the site.....

Its your pump most likely...Next time you turn key on and hear nothing have her crank engine and bang hard on bottom of the tank. I'll bet she starts right up..Fuel pumps fail in this manner often. could be a bad connection or bad bearing etc inside pump..I'm thinking bad bearing with just enough friction to keep it from initially turning. Let us know what you find..

Dick

 

You can continue to guess and randomly replace parts until you go broke and you MIGHT fix it.

OR, you could do proper troubleshooting, locate the fault, replace only the faulty part and for sure fix it.

The next time that it doesn't crank, check fuel pressure, check voltage at the fuel pump relay, etc.

If you don't know how to do these things, get help from someone who does.

Random parts replacement is a BAD way to repair any vehicle.

 

What he said also...

 

Thanks for the input David, I appreciate it. When it does not start fuel pump relay is at 12 volts and fuel pressure is at 3 psi. If I'm not mistaken the pressure should be at 55-80 psi. The 3 psi is with three turns of the key

 

Yep my money is on fuel pump, fuel pump relay, or crankshaft position sensor.

 

You definitely have a fuel problem, as you already know. Before testing the pump, be sure that you do not have a clogged fuel filter and that there is plenty of fuel in the tank. Now, how do we find what is causing the low pressure? You should not replace the fuel pump until you know for certain that it is bad. You can check the voltage at the fuel pump relay to verify that the PCM is trying to turn the fuel pump on. You may need to get a helper to do the test, because you will only have voltage on the load side of the relay for a couple of seconds after the key is turned on. If you see the "prime" voltage on the load side of the relay (battery voltage), then you need to make sure that the voltage is reaching the fuel pump. Make sure that the fuel pump inertia safety switch is not tripped. If that is Ok, then you need to check for voltage at the fuel pump. (Check both power and ground. If either is missing, you may have a wiring problem.) If power and ground at the pump are OK, then you have a bad fuel pump. Now, what if you did not have battery voltage on the load side of the relay? Check for voltage on the control side of the relay. If it is there, but is not on the load side, you have a bad relay. What if you did not have voltage on the control side of the relay? You could have a blown fuse or a sensor input to the computer could be bad. Let's leave it there until you do some voltage checks, then, if necessary, we can talk about PCM inputs and outputs.

P.S. I suspect that your fuel pump has a bad section on the commutator and when it stops on the bad spot, it will not turn. You can try banging on the tank while someone turns the key to attempt cranking it. If it starts, you need to replace the pump. However, what if that does not work? See above for troubleshooting procedure.

 

Thanks David! Sorry for the delayed reply. I got married this week and I have been a little busy. However, I did try everything you suggested and I have narrowed it down to the fuel pump. Thanks for all your input. It really helped. I have the pump on hold and I'm going to pick it up tomorrow.

Instead of dropping the tank, I'm going to take the bed off. It is a 99 with low miles but in Omaha, Nebraska the salt they use on the streets really creates some rust and corrosion. I don't want a tank strap or hose to break on me so taking the bed off will probably be the easiest

Thanks again guys, I really appreciate the help!

 

Unless the bed has been off those bed bolts are probably going to be WAY more work than dropping the tank, and very likely they will have to be cut off and replaced. You may want to look at your bed crossmembers too. They tend to rust before anything else does, if you remove the box and they fall apart you will have to repair them to even get the bed back on and tight.

I just did the pump in my 2000 over here in SW Iowa and dropping the tank was simple. It has 125k on it, the straps are pretty heavy duty and were still in good shape. I siphoned all but about a gallon of fuel out; after disconnecting the fill line from the neck it's much easier to get a siphon hose in the tank. I held the tank up with a floor jack and removed the straps, there is a bolt on the hinge side so they can be completely removed, this gets them out of the way making it easier.

I lowered the front of the tank down enough to disconnect the vent lines at the front and rear. There is enough slack in the fuel lines and electrical to lower the tank all the way and set it on the ground. You will need the fuel line disconnecting tool to get the pressure and return lines off. I disassembled the module and changed the pump inside because everything else was working and in good shape. It's cheaper that way and the parts store didn't have the assembly in stock. Even with my stock height 4x4 there was still plenty of room to work without lifting the truck, even working on a creeper. Start to finish I probably spent less than 3 hours and that included another trip to the parts store due to parts missing from the pump kit.

 

I would take the bed off then drop the tank and see what needs to be replaced behind it like brake lines or those vent metal parts that rust bad. Plus if it needs tank straps replace them..


Dick