Greetings,
I've been registered here for some time now, but haven't posted much. I'm pretty good at doing what needs to be done, but finding the problem is what I have trouble with.
Here goes,
I have a 250 SD 5.4 gasser, working like a charm until last week.
Started fine, drove great, got a coffee at the drive thru and just died.( that made alot of friends)
-engine cranks great, just will not catch
-Have checked all fuses and relays that I know of (in fuse box and underhood drivers side)
-disconnected fuel filter, turned key, gas shoots out (changed while at it)
-no gauge, but pressure at the valve on the rail when valve is pushed in
-accessed throttle body, used starting fluid, cranks great but makes no effort to fire (tried a few times)
Changed the plugs about six months ago ( thanks again to some wonder posts here)

Will something else have caused this, again I'm not great at diagnostics, everything I've done so far has been a result of reasearching the site here, and a many thanks for all the dedicated people here.

Sorry for the long post, but I want to give as much info as I can so there isn't alot of back and forth

Thank You
Stuck in the cold
(literally, It's -5 here)

 

1st thing would check is the fuel pump switch. It is usually on the right side down by the floor. When you sit on the passenger side there is a hole in the plastic side. my understanding is there is a push circuit breaker that is designed to pop out in an accident so you dont pump gas on a burning engine ect matbe noth thopugh since you have gas shooting out.

 

other wise ignition??? what year is it?

 

Sorry, forgot to mention that the inertia switch was checked and seems ok (physically anyway)
Thank you
John

 

It's a 2004

Used a code reader also and nothing came up.

I checked the fuses and relays, is there something buried somewhere that is important

Thanks
John

 

OK 04 I will look it up

 

since you tried ether it is not a fuel issue. So I have asked around here and since it is not throwing a code, you have us scratching our heads.

The 5.4 is really reliable. Sorry. I will be watching this thread to so what it is. Has to be ignition though. Not even a back fire hu?

 

Thanks Mustang,
I have been happy with it, and still am.

No nothing is happening other than just cranking great.

Is there a way to test for ignition electrics and other related issues

Thanks
John

 

One could guess crankshaft positioning sensor??? but how much money do you want to throw at it with out knowing.. I even called a buddy I drag race with and he asked the questions asked. We both scratched our heads. HE is ASE certified and owns his shop.

It sucks in this cold weather At least it cold here. I thought you said it was cold also. Why cant this happen when it is 65 and sunny right??

 

Thats the thing, the less money thrown at it the better, thats why we start with the obvious first.

Well thanks for getting back to me Mustang, I'll probably have to take it in, more of a hassle than anything.

Of course I have been told:

"truck that won't start is inconveinience, truck that won't STOP is problem"

Thanks again
John

 

sounds like a spark problem. i would test the ignition circuit. unhook one of the coil packs and try a plug in it while cranking to see if you got spark. and also check the fuel pressure with a tester. fuel pushing doesnt neccessarily mean adequate pressure. your probably gonna find some stupid relay or sensor at fault. hope you find it!

 

Thanks Boots6868
Do I need to check every coil? If one is out does that cause a no start---just answered my own question-if no spark at one it would be ignition circuit.
If it is, is that some kind of a module that can be tested.


Thanks
John

 

I'm sure you lost the crank trigger or cam sensor or the wires to them. If it won't fire with ether or propane chances are you have neither spark or injectors firing...The problem could be wire related. Conectors, computer, Mice chewing wires etc. I would start with crank, cam etc...


Dick

 

Thanks 99f350sd,

Are there post here to tackle this.
Again, if I am pointed in the right direction I can usually get the job done, it's just finding out what to do with what.

Thanks John

 

first thing.you said you checked the fuses. did you check with a test light, or by eye. i have seen fuses that look good, but are bad.