98 F150 crank no start
#1
98 F150 crank no start
Truck cranks but will not start. Ran fine, shut off and left overnight, next day would not start. No stumble or pop. WOT, closed, partial, doesn't matter.
4.2L V6. Not equipped with anti-theft. Fuel topped and ran about 1/4 tank.
No codes
Fuel rail 40-50 lbs during ignition ON and crank
Fuel smell from exhaust after extended crank
Injected known good fuel behind throttle body, no difference
Fuel inertia switch button depressed
Good spark
Shotgun replace crank position sensor
Swapped around relays
Battery voltage nominal
Thoughts?
4.2L V6. Not equipped with anti-theft. Fuel topped and ran about 1/4 tank.
No codes
Fuel rail 40-50 lbs during ignition ON and crank
Fuel smell from exhaust after extended crank
Injected known good fuel behind throttle body, no difference
Fuel inertia switch button depressed
Good spark
Shotgun replace crank position sensor
Swapped around relays
Battery voltage nominal
Thoughts?
Last edited by cowboypilot; 11-19-2018 at 12:43 PM.
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In your first post, all items reported show normal operation.
Crank sensor should have not been replaced under those condition because everything was working including relays.
Assuming nothing was missed, the ECT code suggest a simple 'flooded' condition.
An ECT code can cause excessive richness because the sensor controls 'average' fuel delivery level at all times.
Be awhere on a V6 there may be two sensors. Be sure you got the one that feeds coolant temperature signal to the computer. At cold starting, the sensor indicates to the computer the coolant is cold along with the intake air temp sensor. This causes the fuel tables to be set rich, advances ignition timing and opens the intake Air Controller to raise the cold idle.
All the same things a carbed engine does with automatic choke.
I would be sure the motor is not flooded first before taking any other action.
The gas smell in the exhaust would be the tip-off because fuel injection does not just stop with a no start unless there is a fuel system fault or extended cranking without ignition. This would be a normal result.
Check the fuel regulator vacuum line for presence of gas. If yes it indicates gas is leaking by the vacuum side into the intake and causing excess richness.
Good luck.
Crank sensor should have not been replaced under those condition because everything was working including relays.
Assuming nothing was missed, the ECT code suggest a simple 'flooded' condition.
An ECT code can cause excessive richness because the sensor controls 'average' fuel delivery level at all times.
Be awhere on a V6 there may be two sensors. Be sure you got the one that feeds coolant temperature signal to the computer. At cold starting, the sensor indicates to the computer the coolant is cold along with the intake air temp sensor. This causes the fuel tables to be set rich, advances ignition timing and opens the intake Air Controller to raise the cold idle.
All the same things a carbed engine does with automatic choke.
I would be sure the motor is not flooded first before taking any other action.
The gas smell in the exhaust would be the tip-off because fuel injection does not just stop with a no start unless there is a fuel system fault or extended cranking without ignition. This would be a normal result.
Check the fuel regulator vacuum line for presence of gas. If yes it indicates gas is leaking by the vacuum side into the intake and causing excess richness.
Good luck.