I have a 1998 F150 4.6L 4x4

So i was driving on the freeway today and i was doing about 70 MPH and then my engine cut off... Temperature was fine my oil was low so i added 3 quarts to bring it up to par. Still nothing so I had it towed by my brother to my house and am now trying to figure out the problem. It cranks over but wont start. I have used starter spray and it will start up with that but wont stay on. I have heard of a safety sensor for low oil that cuts off you engine to protect it from dmg? Is that a possibility? And if so why wont it turn over now? Sorry I am new to all this but due to the poor economy i am forced to fix my own problems. I am a contractor so i am used to getting my hands dirty so i dont mind that. I just feel bad for whoever is going to help me through this might be talking to a 4 year old. lol.....


I have not done much. Read a couple of threads some are close to my problem but not my problem.

Any advice will help.

 

Check for fuel pressure. There is a test port on the fuel rail, you can borrow a gauge kit from most parts stores. If you have no fuel pressure, the fuel pump relay could be bad, the inertia switch may have tripped, or the fuel pump may have died. The fuel filter could possibly be clogged.

It has to be a fuel issue if it fires off with ether.

 

Ok thank you! I will try that in the morning and see where it goes from there. Also i have a 1997 f150 4.6L in my driveway has its own issues but i grabbed all the relays and swapped them out and still no fire. I forgot to mention that ealier. And i have checked my switch and it is not tripped.

 

When was the last time the fuel filter was changed? I'm suspecting that. When you were on the highway and it died, had you just started to accelerate? If the filter is full, one small surge, and you are done. A fuel pressure check will tell you for sure, but if you don't remember when/if the filter was changed, I'd start there before I even checked pressure. It may solve the problem.

Hunt4Fun

 

This morning I checked the fuel pressure and it doesn't even register the pressure on the gauge. It does however fill the line leading to the gauge so it seems like the pump is still working. I'm thinking it probably is the fuel filter. Is that what it sounds like to you?

 

Yes! I never buy a new vehicle without changing the oil, fuel filter, differential fluids, transfer case fluid, and transmission fluid.

 

Ok so i changed the fuel filter and still not getting enough fuel. And yes when i was driving on the freeway it cut off right when i was trying to pass someone. so i did give it a good surge of fuel. It definitely tries to start more now than it did before the fuel filter change. But still nothing on the pressure gauge. Also one more thing i forgot to mention. Prior to this episode every time i would start the truck it would almost always barely turn over.... But i thought it might be a starter problem and am just realizing it could have been my pump slowly dying out on me. Thanks for all the help so far. You guys are definitely making me think more about everything.

 

When you turn the key on, do you hear the fuel pump run for a couple seconds? If not, it's shot or you have an electrical issue.

Normal fuel pressure is 28 to 40 psi.

 

You have not said, so I'll ask the question, after you changed the fuel filter did you try a few times to start it? I ask because it takes a few seconds for the pump to build up pressure. But if you have a fuel pressure gauge and you not seeing any pressure at all it sounds like either the relay or pump. I would double check the inertia switch. I would even pull the wiring harness off of it and put it back on just so that you know that's not the problem. Or you can always jumper the switch temporarily to verify that it is working.

Someone else may have some suggestions on testing the relay and pump or you may try a search for those terms.

 

Yes i did try to start her up quite a few times. I will check the inertia switch again also pull the harness and reconnect it. I know all my relays are good. And how (if not to hard to explain) do you jumper the inertia switch? I am very close to narrowing it down to just the fuel pump thanks to you guys But would like to try that jumpering before i dig into that mess.

 

There are two wires for the switch. If you remove the wiring clip from the switch, make a short piece of wire that is stripped on both ends. Insert the ends of the wire into the clip. The wire is then your "switch" that can't fail. If that doesn't give you fuel pressure, I think the pump has gone out.

You also might check the fuel pressure with the vacuum line removed from the fuel pressure regulator. If the pressure goes up, the regulator could be at fault.

See http://www.ford-trucks.com/forums/98...re-issues.html

 

most likely its a bad pump. 15 year old pump..

 

There won't be any vacuum if it's not running. With it running, the pressure SHOULD go up with the vacuum line removed.

Tyler, can you hear the pump running when you turn on the key? Open the gas cap and listen when someone turns the key on for you.

 

Yes i can hear the pump and yes my bed is off. I am getting 6.5 volts to my pump. from the next connector before the fuse box is still 6.5. I can here the pump trying to work. I was wondering if there is some kind of sensor that could be bad? I have recently replaced my regulator and my MAFS. My connections look fine but still trying to figure out why im not getting the volts i need. I have 12 volts from my fuse and 12 volts from both #87 on my relay and only 6.5 volts on #30. I dont know if im checking wrong or looking for the wrong thing. Thanks for all the help thus far.

 

Ok thank you all for some awesome advice!!!! I removed my bed and to check the pump i bypassed the relay and made sure it got the 12 volts. I heard it working like crazy still no fuel pressure. So i removed the out hose from the pump and hooked up a hose and put it in a pan and nothing came out. So i figured my pump is bad. Replaced it and it fired right up. Also i am still only getting at most 6.5 volts to my fuel pump. But my pressure valve (hooked up to the fuel rail) says its at 40 psi. And i think thats normal so its running im happy!