94 x wont start

[atv nut]

Hello to all. Im new to posting on the internet but I am goin nuts finding a solution to my non starting 94 x with a 4.0. Has 99000 miles on it and the problem started as the weather started getting colder.Now its 25 out and she wont start.New crank sensor,fuel pump,fuel reg,all new relays,air temp sensor,coolant sensor,plugs ,wires,battery.When starting pump primes,but when i let off switch dont hear pump.Cel stays on when starting, but if i keep trying, light goes out and can hear pump for a second,try again and she fires up.Fuel pressure is at 35,although overnight it drains off but quickly primes back to 35. Also new filter. Any help would be very appreciated. Christmas is coming and rather spend money on grandkids than throw parts at the Ford.

 

[MrShorty]

Does the fuel pressure stay at 35 or so while cranking? Does it have spark?

 

[atv nut]

X has 35 psi at start and spark

 

[atv nut]

Took an old spark plug and gronded it,had spark but dont know if its ample . Also checked compression...same on all cylinders within a few lbs.

 

[atv nut]

The problem seems to be with keeping a signal to the fuel pump while the engine turns over.I got a code for a pip signal but dont know if it was caused by engine starving for gas or otherwise. Hoping it is not the camshaft position sensor..toooo expensive and also cant find just the sensor. Could the pcm cause this?? Runs like new whenit does start, with absolutely no problems. Also once it finally starts, will restart perfectly as long as I dont let it sit too long in the cold.

 

[MrShorty]

The problem seems to be with keeping a signal to the fuel pump while the engine turns over.

Why do you say that? If the fuel system is maintaining 35+ psi while trying to start, that suggests to me that the fuel system is working just fine. Unless the injectors are also not firing, which would suggest to me something in the PCM power supply circuit as a first place to look.

A bad PCM could cause this, the difficulty is getting that diagnosis. At this point, it would be a "guess and check" diagnosis. Otherwise, diagnosing a bad PCM is by process of elimination (eliminate all other possible causes and, if they check out, then replace the PCM).

At this point, assuming the fuel system is staying pressurized, I would be checking the PCM power and ground circuits to make sure the PCM, fuel pump, and injectors all have power.

 

[atv nut]

Thanx Mr. Shorty, Ill be checking that the injectors are firing. Just replaced the icm to no avail.

 

[Turdle]

Thanx Mr. Shorty, Ill be checking that the injectors are firing. Just replaced the icm to no avail.

Have someone crank the engine while you feel the injectors
you should feel them "clicking"

 

[atv nut]

UPDATE>>>I had the problem progress as cold weather came in so after the help i got on this forum I thought about what Mr. Shorty said, and i went out and removed my pcm ,took the cover off and heated it up with a hair dryer. I went back out and layed it in the floor, hooked it up and it fired right up. Must be a bad solder joint in the board.. Thank you tremendously for your help.

 

[atv nut]

Thanks also to Turdle for your input....the fuel injectors were not clicking. This is a very good site, especially for someone like me who doesn't have the money to pay someone else, but has enough ability to do for themselves and have some good input by others to help brainstorm a problem..Thanks again.