Where is the CPS? Looking from underneath, is it the one connected to the wires that end up just behind and to the passenger side of the crankshaft pulley, kind of stuck up in the front of the AC compressor? If so, has anyone changed one? What is the best way to do it? What should come apart first? How long should it take? Any tricks or watchouts? Thank you!

 

Yup, that's the one, should be in the side of the timing cover. No particular trick to it.

Why are you replacing it?

 

Thanks Krewat, If that's the one, it looks like I'll have to remove the belt and drop the AC compressor. Is there anyone who has done this and is that what needs to be done?

I'm shotgunning parts because I've had a frustrating time diagnosing my problem. Even Ford couldn't help. It just occasionally dies like someone turned the key off. Then will not start for 5 minutes, but always does restart. Sometimes it'll happen 4 times a day, other times it won't happen for weeks. I've tried new fuel pump and filter, and a Throttle Position Sensor. By consensus, CPS is next on the list.

 

Yup, that's where I'd start. Heats up and expands, bad connection opens, no signal, stall, no restart. Cools off, contracts, bad connection closes.

However, next time it does it, check for +12 at the COPs and injectors with the key on. Forget the color of the wire, but it's one of the two on each connector. If you don't get +12V, you have a power supply problem.

Better yet, get a spare COP, and when it won't start, pull the connector on one of the COPs and put the spare on it, put the tip near ground and crank and see if you have spark.

 

Sounds reasonable. I'll just have to make sure I have a capable passenger next time it dies. Another thing that might give you some insight is sometimes after it dies it will just crank with no start. Sometimes it will start but will only give me a sputter idle with no response from the accelerator, then die after 10 seconds of that. Either way, after five minutes it always starts with its standard roar.

 

that really sounds like loss of fuel pressure. The "sputter" thing indicates the fuel pressure is too low to feed the engine.

The fuel pump usually won't just die while running. Sounds more like the fuel pump relay, inertia switch, etc. In your case, with the 3-valve, you have a fuel pressure sensor. If you get an OBD-II bluetooth adapter and use Torque on Android, you can check the fuel pressure readings.

 

Is the V10 in a 2005 Excursion a 3 valve?

 

X2 on checking the fuel pressure.
Not sure how that's done on a 2005, I think the test port on the fuel rail was deleted by then.
Also, I would monitor the voltage at the output of the Inertia Switch in case the fuel pump relay is acting up.

 

DOH! It's an X, so it's a 2-valve, sorry for the misinformation.

You should have the typical Schrader valve in the fuel rail I think. Easy to check. See if there's something with a black cap on it on the fuel rail near the back of the passenger-side. Unscrew the cap, there should be what looks like a tire valve in it.