'14 F150 no codes...no start

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3.7L, 130k , no CEL, running fine. Drove down to Tractor Supply for a few things, got in truck, turned the key and it spun fine (no battery issue), stumbled and died. Tried again, spun and spun and no start. Plugged in my Torque Bluetooth, no codes. Popped hood, checked all relevant fuses for PCM, fuel pump etc...no problem. I was about to call the tow truck, when I remembered that I changed the MAF earlier in the year after getting an Intake Air Temp code (part of MAF assy). As a matter of course,when I changed it out I threw the old one in the box and threw it in my toolbox. I located it, popped it in and it fired right up (yes I checked the connections on both the throttle body and the MAF prior to this). Not sure why it all happened the way it did...but hopefully it will help someone else. Enjoy !
 
Interesting... aftermarket or OE MAF?

Odd for it to fail to the point of a no start like that. Good thing you had the old one on you.
 
Something else is going on. Your car stars on an "Open Loop" system with factory preset values (other than the coolant temperature sensor) and then it closes the loop and starts listening to all the sensors. It's a coincidence that it started. I bet if you put the old one back in place it will still start.
 
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Autozone brand....and something else may be happening...but to work through all those things, only to have it start....could be a coincidence , time will tell.
 
A detail I left out...the first time , each time, after I would remove key, open door and check something it would kind of start, but never got to rpm, stumbled and died. If I never removed key...each time thereafter it would just spin but never catch.
 
I know it's premature but you have the symptoms of a failing fuel pump.
 
Originally Posted By: StevieC
Something else is going on. Your car stars on an "Open Loop" system with factory preset values (other than the coolant temperature sensor) and then it closes the loop and starts listening to all the sensors. It's a coincidence that it started. I bet if you put the old one back in place it will still start.


Plenty of cars will crank but not start if the MAF is disconnected
 
Originally Posted By: Ethan1
Originally Posted By: StevieC
Something else is going on. Your car stars on an "Open Loop" system with factory preset values (other than the coolant temperature sensor) and then it closes the loop and starts listening to all the sensors. It's a coincidence that it started. I bet if you put the old one back in place it will still start.


Plenty of cars will crank but not start if the MAF is disconnected


Fords Ive played with will start and even run reasonably well without the MAF. Ive done it a few times on accident (left MAF unplugged). What tips me off when I do it now is the transmission shifts rougher. The load in the failed MAF table is higher than what it would actually be probably for safety so it calls for more trans pressure.
 
Originally Posted By: travlnman
Autozone brand....and something else may be happening...but to work through all those things, only to have it start....could be a coincidence , time will tell.

I have tested these before disconnecting them and the engine should run.
 
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I always forget to reconnect the MAF when,changing air filters and never had one not start or idle. Driving is a different story.

It sounds like a fuel pump or heat soaked failing sensor
 
Originally Posted By: Colt45ws
Originally Posted By: Ethan1
Originally Posted By: StevieC
Something else is going on. Your car stars on an "Open Loop" system with factory preset values (other than the coolant temperature sensor) and then it closes the loop and starts listening to all the sensors. It's a coincidence that it started. I bet if you put the old one back in place it will still start.


Plenty of cars will crank but not start if the MAF is disconnected


Fords Ive played with will start and even run reasonably well without the MAF. Ive done it a few times on accident (left MAF unplugged). What tips me off when I do it now is the transmission shifts rougher. The load in the failed MAF table is higher than what it would actually be probably for safety so it calls for more trans pressure.


Zetecs won't. From what OP is saying, it sure sounds like the Duratec/Cyclone 3.7 won't.
 
I forgot to plug the MAF back in when I put the new intake pipe on my 5.0. It started but the cluster lit up like a Christmas tree and it was not happy at all.
 
Originally Posted By: Ethan1
Originally Posted By: Colt45ws
Originally Posted By: Ethan1
Originally Posted By: StevieC
Something else is going on. Your car stars on an "Open Loop" system with factory preset values (other than the coolant temperature sensor) and then it closes the loop and starts listening to all the sensors. It's a coincidence that it started. I bet if you put the old one back in place it will still start.


Plenty of cars will crank but not start if the MAF is disconnected


Fords Ive played with will start and even run reasonably well without the MAF. Ive done it a few times on accident (left MAF unplugged). What tips me off when I do it now is the transmission shifts rougher. The load in the failed MAF table is higher than what it would actually be probably for safety so it calls for more trans pressure.


Zetecs won't. From what OP is saying, it sure sounds like the Duratec/Cyclone 3.7 won't.

Note there is a difference between a bad signal and disconnected. When its unplugged, the computer knows its not there and can fall onto failure mode effect management immediately. As soon as you go key on with no MAF it will set multiple pending codes. You dont even have to crank. A bad signal may prevent it from starting and figuring out that it has failed.

Also, there is an easy way to check if the crank sensor is bad: Watch the check engine light.
So going key on, the light will be lit.
When you go to start and the engine cranks, its should go out and stay out for the duration of cranking. If it doesnt, the PCM is not getting a crank signal.
 
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It's not the fuel pump.

.
It is the fuel pump driver module that failed.

It on the frame crossmember above the spare tire.

.
 
My vote is for a failing temp sensor...probably the one in the MAF. The car may start open loop, but it still uses readings from the temp sensor to start correctly. If the sensor says it is much warmer than it is, it won't inject enough fuel for the engine to catch.
 
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