2010 F150 XLT 5.4l cranks, no start, no codes in PCM, Gauge cluster, or GEM.

[funguy26]

I been working for this f150 that the dealer could not get going. It cranks, not starting, and no codes. fuel pump working, got fuel pressure 60psi, there is no spark, the injectors are not pulsing. My scanner is getting a reading back from the PCM Cranking fuel Disable: Yes Disable. I look in to the Gauge cluster no codes in here, look in to the BCM (GEM) no codes, and Air bag module no codes. there is a few codes hanging out on the truck in other system like in the HVAC, and radio. The only other thing that comes to mind is the GPS system not responding.

 

[adsm08]

In the PCM PID list there should be one about PATS enable/disable. What's that say?

 

[RonD]

So did you try the 50/50 test to confirm no spark, i.e. spray fuel into the engine and try to start

The starter motor is working, and I assume no flashing THEFT light, so not a PATS issue

The spark and fuel injectors both need a timing pulse from the crank sensor so they can start working

The CEL(check engine light) will go OFF if PCM is seeing this pulse, so watch CEL, should be on with key on(PCM booting up) and then it should go OFF when starter motor is turning the crank, that means PCM is getting timing pulse
If it doesn't go OFF I would start at crank sensor and its wiring

 

[funguy26]

In the PCM PID list there should be one about PATS enable/disable. What's that say?

is Enable

 

[funguy26]

So did you try the 50/50 test to confirm no spark, i.e. spray fuel into the engine and try to start

The starter motor is working, and I assume no flashing THEFT light, so not a PATS issue

The spark and fuel injectors both need a timing pulse from the crank sensor so they can start working

The CEL(check engine light) will go OFF if PCM is seeing this pulse, so watch CEL, should be on with key on(PCM booting up) and then it should go OFF when starter motor is turning the crank, that means PCM is getting timing pulse
If it doesn't go OFF I would start at crank sensor and its wiring

There is no spark the starter is cranking the PATS is working. I put a another pats key next to the tranponder and cluster set a code for a unknown key and disable cranking. I replace the Crank sensor. tested both cam sensor there working. the wires are good.

 

[funguy26]

Let me add I have replace the crank sensor check the wires while I was there, test the cam sensor and wires. The pcm is seeing the engine turning over. I though the PCM was burn out replaced it with a used one. when in to the PATS system and reset the cluster for the replacement PCM.

 

[adsm08]

is Enable

OK, security system is not the issue.

What is the cranking RPM PID reading?

 

[RonD]

Yes, +1 ^^

Don't care about crank sensor just care about PCM seeing crank sensor timing pulse
Does CEL go off when cranking?

There is no "spark test" for any engine except a single cylinder lawn mower, lol
When there are two or more cylinders you do the 50/50 test, simple and easy, with instant results

If 50/50 has a no start then you have spark OR Compression issue
So next step is to pull a spark plug and test one cylinder for compression, if above 120psi, THEN go to spark as the issue
Or put a vacuum gauge on and crank engine, should see 2" of vacuum if compression is OK

As much as I like electronic diagnosis it is no replacement for hands on tests, you end up chasing your tail

 

[funguy26]

OK, security system is not the issue.

What is the cranking RPM PID reading?

my scanner is coming back as 0 rpm check the sensor got a voltage reading as as low .256v to as high .603v. I screen shot the scanner. The cam and crank is coming back not in sync, crank fueling disable: yes, vehicle enable status, Enable

 

[funguy26]

Yes, +1 ^^

Don't care about crank sensor just care about PCM seeing crank sensor timing pulse
Does CEL go off when cranking?

There is no "spark test" for any engine except a single cylinder lawn mower, lol
When there are two or more cylinders you do the 50/50 test, simple and easy, with instant results

If 50/50 has a no start then you have spark OR Compression issue
So next step is to pull a spark plug and test one cylinder for compression, if above 120psi, THEN go to spark as the issue
Or put a vacuum gauge on and crank engine, should see 2" of vacuum if compression is OK

As much as I like electronic diagnosis it is no replacement for hands on tests, you end up chasing your tail

compression good check it lowest was 140psi highest 150psi. is a PCM input issuse there is fuel pressusse 60psi. the injecters are not pulsing they have power and the coils have power. 12volts.

 

[RonD]

Does the CEL go off when cranking?


PCM has no connection to STARTING system, 0, none, nada................
You can crank an engine until battery dies and PCM will just sit there happily WAITING for you to tell it to start spark and fuel
CEL goes OFF when PCM sees you telling it to start, crank sensor AC Volt pulse

 

[funguy26]

Does the CEL go off when cranking?


PCM has no connection to STARTING system, 0, none, nada................
You can crank an engine until battery dies and PCM will just sit there happily WAITING for you to tell it to start spark and fuel
CEL goes OFF when PCM sees you telling it to start, crank sensor AC Volt pulse

I checked this is on when i crank it. So go back and check the wire to the Crank sensor.

 

[adsm08]

There is no "spark test" for any engine except a single cylinder lawn mower, lol
When there are two or more cylinders you do the 50/50 test, simple and easy, with instant results

I can test spark on any engine that isn't a diesel. All I need is a #2 philips screw driver and a second person.

 

[adsm08]

I checked this is on when i crank it. So go back and check the wire to the Crank sensor.

I would tap into the wires for the crank sensor AT the PCM, or as close as you can get, and see if you have the same AC voltage reading as you do at the sensor.

 

[RonD]

I can test spark on any engine that isn't a diesel. All I need is a #2 philips screw driver and a second person.

Not possible
Even if that second person JUMPS when they get electrocuted you are still missing if it was just key on spark or cranking spark

50/50 test does TWO things
Tests spark and spark TIMING, quick simple and accurate
Three things if you count compression, and we always count compression, lol