I just bought a 2003 F150 4WD XLT with the Triton 5.4 Liter engine with ERG valve. Vin code L I bought this truck Knowing the engine was not running according to the previous owner he was driving along and the engine started to buck like it was running out of gas. He called a wrecker and had it towed home. I bought it in its present condition. Here is what I have found or checked so far.
The engine will crank, but not start.
I put a OBDll scan gauge on it and it gave me a code of PO420
I checked the fuel reset button and it was OK. I wanted to check the fuel fuse but cannot open the door to the panel under the hood to do so. I do not want to pry on it for fear of breaking the door or lid. Is there some special thing to do to unlatch it? It appears that this engine has the I think it is called the Cap or Cop ignition system. (coils on spark plugs) I am not familiar with this system. I am trying to trouble shoot the system to find out why it won't start. Fuel system, Ignition system and Oxygen. Any help appreciated.
Mel

 

That truck is equipped with the PATS system, the chip key must be registered in the PCM or it will not start. If that is the problem, the theft light in the dash will continuously flash. Turn the key to "run" but don't start it. If the red theft light goes out the key is good.

Air is easy, make sure the filter is clean and all the tubing to it is clear. MAF sensor in the air cleaner box needs to be connected and clean. All the tubing from the filter to the throttle body MUST be sealed.

For fuel the first easy thing to do is test for pressure on the fuel rail at the engine. There will be a Schrader valve on the shiny chrome looking fuel rail on the engine. Try to start it a couple of times then push on the Schrader valve to see if any fuel squirts out. If it is working right it should be enough fuel to catch you on fire so use a rag or something and don't smoke. Or better yet put a fuel pressure gage on that Schrader valve to check the fuel pressure. Should be 30+ psi to start it. You should also be able to hear the fuel pump run for a couple of seconds when the key is first turned on.

The coil on plug or COP system has a coil on each plug instead of a single coil pack for multiple cylinders. This results in a stronger spark. To check for spark, pull off a coil that is easy to get to (7mm socket), stick a spare spark plug on it, ground the plug, and have an assistant engage the starter to see if it is firing.

 

Thank you for the info I will do this tomorrow and get back with my findings.
Mel

 

Once you determine the PATS is accepting the key, the next quick thing to try is starting fluid. If the engine fires up using starting fluid you know it's a fuel delivery issue and not an ignition or compression one.

 

I hooked up a fuel pressure test gauge and got zero. When I removed the gauge, The truck tried to start for just a second. I did like you said using starter fluid and the truck started and ran for a few seconds. Guess it is fuel. fuel Filter, pump, or ?
Mel

 

Where is the fuel filter located? I don't see one in the engine compartment. need to check the filter before I go changing a fuel pump. Also I can't get the lid or hinged door to open on the underhood fuse block to check the fuel pump fuse. is there some kind of latch that needs to be depressed or is it just hard to get open.
Mel

 

Just going from memory, it seems like the fuse box lid has a latch toward the back of the truck and the hinge is on the front side.

Check for voltage at the inertia switch, that way you can split the fuel pump power circuit in half. Remember that the fuel pump only runs for a couple of seconds when the key is turned on. You might try banging your fist on the fuel tank while someone else operates the starter. Sometimes that will jog a failing pump into running.
Laying there right next to the fuel tank you should hear the pump prime when someone turns on the key.

Fuel filter is under the truck, slide under driver door area and you should see it. The filter requires a special tool to unfasten the hose connectors.

 

Yes that is the fuse box, and mine is the same as you describe, but I can't get the latch to release so I can raise the lid. not sure what kind it is or how to get it to release.

I will check the voltage at the inertia switch.

I sprayed Starting fluid on the air filter and the truck started right up, so it is a fuel issue. I would think that the fuel pump would be running as long as you are cranking the engine.

I will try banging on the tank while cranking the engine. They are made of plastic. LoL! I ordered a new filter and filter removal tool from Amazon. will be here Monday.

If I have to change the fuel pump I will probably remove the bed rather than dropping the tank.

Thanks for your help and info. will keep the forum posted as I progress.
Mel

 

I am more a fan of dropping the tank. If it is nasty or rusty inside you will want to take it out and clean it anyway. It is really not that big a deal to drop the tank.

As far as when the fuel pump runs, it primes the rail to build up pressure for a couple of seconds as soon as the key is turned to run. And then the fuel pump stops. After that the PCM looks for a signal from the crank position sensor to see that the engine is turning. If that signal (engine is spinning) is there, then the fuel pump engages.

The power distribution box under the hood has one latch as shown. Using my left hand, I wrap a finger around the back edge and curl the finger upwards.


power distribution box latch 2003 F150 V6

 

My feeling is the replys are sort of out of order.
You first need to eliminate the PATS as a possible cause of a no start.
Turn on the ignition and let it set at least one minute to see if the THEIFT light flashes a code.
If yes what is the two digit code. It will be the cause of a no start.
If no code, proceed to test fuel pressure at the test port on the fuel rail.
To do the test, cycle the key to ON several times and check the pressure that should develop. It should be about 35 psi and hold at least 10 minutes with the key OFF.
Do these checks before going to a lot of labor, to find out what is the exact trouble.
Obviously, start fluid that causes the motor to run indicates a lack of fuel.
Is it the PATS or the fuel system or even both.
.
How the fuel system works:
Key to run causes the PCM to ground the fuel pump relay for about 3 seconds then drops out. This is normal operation.
Once cranking begins the PCM re-operates the fuel pump full time to pressure the fuel rails.
You need to use common sense based on how the systems work in general to see where and what the failure might be.
Otherwise confusion reigns.
You bought a truck with unknown history so need to go about trouble shooting with some order and expect other issues to appear as time goes on..
Good luck.

 

Thank you for the image that helped very much. I will get under the truck tomorrow if it has stopped raining and see what all I need to do to drop the tank. I do know there is a skid plate to remove. according to Chilton manual.
Mel

 

When I first started to try and determine the problem I hooked the fuel pressure test gauge to the rail at the schrader valve. I cranked the engine for 15 seconds read nothing on the gauge. I also unhooked the gauge from the test hose and put the hose in a coffee can and cranked the engine for another 15 seconds. I got maybe a tea spoon full of gasoline in the coffee can. I have not seen any warning or theift light come on. I also tried both ignition keys. I will try your method and see if I get any results. Will keep the forum posted.
Mel

 

The PATS will shut power to the injectors not the fuel pump. So if there is no pressure then the problem is likely the pump. Even a dirty filter will pass some fuel and since there is none, then that moves the pump to the top of the 'likely what's wrong' list.

 

Thank You for the reply, It is as I suspected, but will do as others have said just to be sure. I would hate to pull the pump only to find that it is working. It is cold today 33 deg F and it rained last night so it may be a couple of days before I do anymore testing.
Thanks again
Mel

 

Just a note.
You will not get the pump to run by cranking the engine over with a no-start.
One reason is possible flooding that could happen if there is no ignition.
Repeated key cycling will run the pump each time.
This is the way to re-prime the injection rails if you run out of fuel and put some in the tank to get going again.
Cranking after the initial key on likely will not cause the PCM to turn the pump on.
The program monitors the RPM just 'above' the cranking level from the key on short time pre pumping for engine firing before actually turning the pump on. (same as if you spray fluid in the intake) for testing.
Cycling the key on several times give you most all the info you need except flow volume.
You must understand these 'little' things because they are engineered into the system operation for a reason.
.
Most just think turning the key on runs the pump full time.
Doesn't work that way.
Another big reason is a fire hazard. In event of a crash the inertia crash sensor is there to stop the pump from feeding a fire by shutting it off.
This is on all vehicles with electric fuel pumps.
What you want to know does the pump run and does it produce the required pressure.
Good luck.