2003 XLT- Truck died, P0320 and battery light

[Jay87LX]

Hi Guys,
I just bought a 2003 XLT, 5.4, 93K, a clean, well maintained truck. I was on the highway yesterday and the truck died, coasted to the side of the road and called a tow. It did set the eng light and a P0320 code. As I was waiting for the tow it would start and run but after 30 sec of idling it would die, like it ran out of fuel or if I started it back up and reved the enging as soon as it came back down it would die but start right back up.
After some research I am lead to a Crank pos sensor, no problem, I replaced it in my 99 so no big issue, but I also read to look for the harness that comes from the alt to the battery as it rests on the AC tube and can wear through and short, I looked at the wire, pulled the tape back and there is no wear at all.
So I started the truck and the battery light is still on so I took a jumper wire and went from the alt to the battery, basically in my mind replicating the fusible link but the battery light didn't shut off, maybe that wasn't the right way to test it but in my mind I tried it.
It almost seems as if, coincidently, I got 2 problems at the same time? the P0320 (crank pos sensor) and the battery light or are they connected?
I am also confused as it seems it would run out of fuel? is that because once the ckp isn't sending a signal it shuts the fuel off??

Any direction to head or just replace the fusable link harness between the alt and battery as well as the CKP sensor??

I know this is simple maintenance stuff but other than this I love the truck

Thanks

 

[Bedrck47]

I would also suspect the fuel pump relay/fuse box or the fuel pump

Look at this video on youtube

2003-2006 Ford Expedition Crank No Start Diagnosis

 

[Jay87LX]

I would also suspect the fuel pump relay/fuse box or the fuel pump

Look at this video on youtube

2003-2006 Ford Expedition Crank No Start Diagnosis

OK, I will run that test, but why does it seem I have 3 situations, the Fuel issue P0320 as well as the battery light??

In an effort to diagnose the battery light I tested the battery 12.6v. I then started the truck and tested voltage at the battery and while running its 11.4v with loads on. I wiggled the fusible link around to see if it had an effect on the reading and it did not.
I guess my question is is it possible I have 3 issues making happen all at once, (battery light, the P0320 code crank pos sensor, and the fuse box, fuel pump relay) I went on a 420mile trip with zero issues 2 days before

 

[Hamfisted]

Bad alternator to start with. Go from there. If it hasn't already been replaced the fuse box is about due too. (But that fuel pump micro relay will cause the PCM relay to buzz when it fails...). Pull the PCM relay (top right corner of the fuse box...) and check for melted plastic around the terminals... Crank position sensor fail is pretty rare on these motors. Did you get any service records with the Expy when you bought it ? Try running it with a battery charger plugged into it see if anything changes.


-Mike

 

[Jay87LX]

I will start with an alternator this week. The previous owner had just replaced the battery and I am now suspecting because of a weak alternator so he went to BJ's bought one without testing anything.
I did have to replace the CKP on my 99 so at nearing 100K I will replace it on this one and keep the current as a spare.
Once I install the alt I will start inspecting the fuse box that houses the fuel pump relay and test, being a common issue I will more than likely replace it as preventative maintenance as I hate being stranded.
One question I have is in looking up alternators on Autozonepro dot com, there are two different alternators, a 110 amp for trucks without nav and a 130amp for trucks with nav. I was wondering if I can use the 130amp despite not having nav, I know it will bolt up but don't want to send the comp in a frenzy, I would like to take advantage of the extra amperage

 

[Bedrck47]

You be OK using the 130 Amp alt.

 

[docraymund]

Don't replace parts yet if you don't need to. Check the alt with the voltmeter at the alt itself to rule out bad wiring. As for the crank sensor, you need to check the connector for the 5 volt reference signal. If it is present, keep the meter connected while you wiggle the line along its length to locate any intermittent breaks. Also, check the harmonic balancer for signs of failure which could offset timing. Good luck!

 

[Jay87LX]

Don't replace parts yet if you don't need to. Check the alt with the voltmeter at the alt itself to rule out bad wiring. As for the crank sensor, you need to check the connector for the 5 volt reference signal. If it is present, keep the meter connected while you wiggle the line along its length to locate any intermittent breaks. Also, check the harmonic balancer for signs of failure which could offset timing. Good luck!

when I checked the alt I checked at both the battery and the alt. 11.4v
I will report back once the new alt is installed (130amp )

 

[Hugh Janus]

Charge battery - then see if it runs. Hard to isolate between battery and alternator on non-running vehicle. Running voltage across battery terminals should be around 14v with healthy alternator.

 

[Jay87LX]

Charge battery - then see if it runs. Hard to isolate between battery and alternator on non-running vehicle. Running voltage across battery terminals should be around 14v with healthy alternator.

See post #3, truck starts and runs,