I have a 1999 F450 Super Duty. Everything was fine until one day it just quit on me. It starts right back up and runs fine until it suddenly quits again at some point. Sometimes it'll do it several times within a minute or two. Other times it'll run for days without an issue so it's very hard to troubleshoot. I've tried 2 new camshaft position sensors. The connector looks good. I've wiggled the wiring harness around to see if I could get it to hiccup but I haven't been able to. Anyone have any suggestions where to look or what I could look for?

 

Try unplugging the fuel bowl heater.
Also, you didn't mention what brand the sensor you used was. Motorcraft only on all of the engine's sensors

 

I'm not 100% sure what brand of sensor is in it now but it's an aftermarket one. The first time it was replaced at a repair shop. I know he gets a lot of his parts from CARQUEST but sometimes directly from the Ford dealer too. That one looks a little different from the one I put in. The end was a little larger diameter than the one I put in.

 

Sometimes it doesn't shut off either. Sometimes it just hiccups a few times and then either shuts down or goes back to normal without the engine dying. It's very quick like if you shut the key off and right back on really fast so the engine stays running. What's the chances of the ECM causing this? If that's a possibility can it be checked without replacing it? If not, would the ECM from my 2002 and 1999 be interchangeable?

 

Check out your IPR too, is the tinnerman nut still on it and tight? When it quits try cooling the IPR with water or spray air and see if it helps. Failed IPR's show their symptoms when they're warm/hot.

 

When it quits it'll start again right away every time. Sometimes when it happens it doesn't completely kill the engine so whatever it is it's a very quick and intermittent problem. I'll check the wires to the IPR. I'm not sure which tinnerman nut your talking about.

 

The tinnerman nut is a nut formed out of sheet metal that hold the coil onto the IPR, they have a way of coming loose and falling off into the valley.

 

You can see the nut at the end of the IPR in this picture. (do not use the part number as a reference because I pulled the image off Google)

 

[QUOTE=Sous;18088196]You can see the nut at the end of the IPR in this picture. (do not use the part number as a reference because I pulled the image off Google)

Ah. It does have the nut on it. The connector that the wires plug into seems a little funny. It's loose on the sensor like it can rotate around it somewhat or twists...... I can't see in there very well to see what it's doing but maybe that's the way it's supposed to be. When I was in there wiggling the wires and the sensor it had a couple very minor hiccups. One of the diagnostic codes said something about seeing a voltage higher than 33 volts and the other was a generic code. I accidentally cleared them so I'm not 100% sure what they were. I took it for a 20 mile drive and it ran fine but it has done that before too and then will suddenly act up again. When I got back there was a P1211 code.

The wires going to the fuel bowl heater were off. Could that cause the intermittent error code looking like a camshaft sensor circuit? Doesn't seem like it would but there was a reply earlier that said to disconnect it and see if that made any difference.

 

I had a failing IPR that caused instant stalls at any engine speed, and early on in it's failure it was occasional with quick restarts, then became very frequent with longer waits before restarting. Having Torque Pro allowed my to see high IPR % with very low ICP. It could always be something else though. If you can get Torque Pro to log data; ICP, IPR%, RPM (CPS), FIPW; you might see which signal is disappearing and causing the stall.

 

The fuel bowl heater/water in fuel can cause symptoms like a failing ipr/icp and KeepAliveMemory codes. Unplugging it is a free and easy diagnosis, almost like unplugging the icp sensor. Since you say it was already unplugged it may have already been an issue and the PO left it unplugged. I live in a warm enough climate i just left mine unplugged when mine went bad.

Since you are unsure of the brand of Cps you may want to swap in a known good Motorcraft/International Harvester one from a friend. These can be bad right out of the package on some brands

 

After I plugged the fuel bowl heater wire back in it hasn't acted up. I've only driven it 40 miles or so but I've also let it sit and idle for an hour or so and it hasn't done it again. I have two new codes now though. P1211 and P1247.