2006 f250 txr no spark

[boscoe99]

Let's see! My guess is the 5 amp fuse to the lift pump blew.

Here is a hint.

"intake air pressure at key on engine off 17.6"hg.
baro at key on engine off 29.6"hg."

If the actual barometric air pressure is 29.6" Hg but the engine is reporting that air pressure as 17.6" Hg, might there be a problemo?

[oldmako69]

One hell of a hurricane!

[rodbolt17]

at key on engine off baro and intake air should be the same.
at key on the engine baro and then looks at intake air once running as an indication of engine load.

the culprit in this case you ask?????

the last mukanik broke the oil pressure sensor while changing the oil filter.

the 5V ref was shorting and loading down the circuit.
the MAP,water pressure,speed and oil pressure share the same 5V ref.

another dealership had given up on this motor.

took me about 10 min to find and fix it simply by observing.

turned the key on, opened YDIS.
as soon as I saw the descrepincy I unplugged the speed sensor, no change.
I then unplugged the oil sensor, bingo. baro and intake air both read about 29.6"Hg.
replaced the oil sensor and it ran.
this motor did not have a water pressure sensor.

yea
sometimes it is that simple.

[johnny1984]

Rodbolt, A development! Motor will start 5 out of ten times, if it does not start, I just touch the trim button (up or down) starts every time. I dont even have to move the motor up or down, if its right down I just can press down (one touch) and it starts.. trim/tilt relay? or problem in the harness? or.....?

[pstephens46]

Bad connection somewhere......

Well maybe...Just reread the part about motor not needing to move

[99yam40]

bad connection .
could be + or-.

bumping the T&T gets a current to jump across the bad connection and get a temporary bridge across the bad connection.
my guess anyway

[rodbolt17]

my guess is a bad connection or keyswitch.
when you hit the trim it must wake up the ECU.
the ECU controls the trim motor relay.
when you hit the trim listen for the throttle assy and the fuel pump to wake up.
it should do the same at key on.
when you hit the trim with the key off you should hear the throttle assy whine for 10-15 seconds.
at key on it whines all the time.

[johnny1984]

Thanks all.

Rodbolt, what can I say, you were spot on! It was a bad connection, just that. I passed on your message to the "mechanic" after an hour or so, he found it.

thank you so much and everyone else (Trump supporters or not) for your helpful replies.