7.3L PSD stalling - what did I do?

I changed the oil, oil filter, and fuel filter this weekend for the first time on the F250. Changed the t-stat too and hooked up a bluetooth transmitter to the OBDII port for the Torque Pro gauge app. 1996 7.3L powerstroke diesel with 230k miles for those just joining the show. This morning it stalled repeatedly trying to drive it to work. Since it ran fine before I did the work, I'm thinking I did something to it. Specifically, I'm wondering about repriming the fuel system after the filter change - which I did not do.

Details of the behavior -

Saturday I did the work and then moved the truck down the driveway and back but didn't really drive it. I did let it idle for a while (8-10min?) It seemed fine.

This morning was cold (28F) but we had a couple mornings last week that were about the same and the truck ran fine. Last week I'd plug the block heater in an hour before I'd crank it, but this morning I did not. It took a couple tries to start (seemed cold, duh) but once fired it seemed to idle okay and started to smooth out. I hopped out and went into the shop to find an ice scraper to cleat the windshield, figured I'd let the truck warm up a little. While I'm in the shop about a minute later I hear it shut off. No stumble, just off like you turned off the key.

I walk back out and crank the truck. Cranks right up. I start scraping window. Truck shuts off half way through. I finish scraping and crank her up, starts fine, idles fine. I rev the engine up, get the RPMS up to about 2k, hold them a bit. Seems fine. I'm thinking at this point that maybe I'm having a voltage issue since the truck's cold and the alternator doesn't start charging till I've driven to the end of the street usually. I drop it in gear and head out. I make it to the stop sign and it dies again. Alternator still isn't holding solid, but was up to mid gauge when it shut down. I decide to get it back to the house. It stalls three times in the 100 yards back, and a couple times I can hear the rpms drop for a second but not actually shut down. Halfway down the street I unplugged the OBDII transmitter, thinking it might be freaking out the PCM. No change. Every time it's like you turned the key off. No stumble, just off.

Once in the drive way it stalls at the one narrow point where I can't get past it and for once, won't re start. Engine spins strong, just won't fire. I sit for a minute trying to figure out how I'm going to push this beast out of the way by my onesy so I can get another car out of the drive to go to work. After a couple tries it fires up and backs out of the way, running fine.

So..It was running fine last week, I worked on it, now it doesn't run. Logic says it's something I did or affected. Probably. First thing I can think of - I didn't reprime the fuel bowl. It was about half full when I put the new filter in, I did let the truck idle a while in the shop and moved it around with no problem. Am I suddenly just sucking air bubbles? Seems like it would stumble or something, or would have worked it's way out after a few minutes, but...?

Other possible issues -

as mentioned, alternator charging is flaky, but it had enough power to spin hard every time. Don't think that's to blame.

Ignition switch is loose, you can pull the key out and the truck still runs, rattling it around makes the door chime come and go even in the lock position. Didn't try wiggling it while running.

I haven't changed the CPS, but I have a new one to go in. Could the cold affect it that way? Or is the CPS one of those things that pops like a light bulb, not a come and go issue?

Other ideas? What do I need to test? If it were a gas motor I'd be looking at ignition system from the symptoms, but with a diesel...I'm not sure what to check.

Did it cut out and die or stumble/misfired and die?

If it stumbled and died, it maybe a going out injector driver module box on the drivers inner fender under the hood. I would ohm out the injectors from the plug there just to see if an injector is going down instead.

If it was a cps when the motor is dying, the check engine light will come on and you will lose throttle control, it would only idle.

Oh and diesels are still suck, squeeze, bang, and blow. It's just that compression causes the bang instead of spark.

Sound like you got air in the line. there is likely some sort of procedure for bleeding it. Also look for a air leak around the filter (if it has sat a bit you might find fuel drip where the air leak is around the filter housing.

Simple question would be is your fuel gelled?

Usually if you don't purge well enough or tighten the fuel filter it will die after the initial start up, but once running enough to get down the street will be fine. Did you fill the filter with fuel before installing?

I had this problem with a 7.3IDI. It turned out the idle valve in the injection pump was sticking. Does the truck have 2 tanks? Once the solenoid between the tanks gave up. The dash said I was running a full tank, but I was actually on the empty tank. Is you high idle working?

I would suspect the CPS. I never changed mine under the recall, and a couple of times I have had phantom stalls.

It shut down like you turned off the key. No stumble, no lug down, and fired right back up almost every time. When running it ran smooth and sounded fine. Throttle control was fine.

Just filled the rear tank, still showing 1/4 on the front tank and the selector has worked fine for the 2 weeks I've had the truck. Fuel isn't old - well, in the rear tank I'm running on anyway. And I've run it on the front tank and it was fine, but not sure how old the fuel is. I don't think 28's cold enough to gel the fuel, is it?

It idled fine...not sure if it was high idle or not though. Seems like the tach was between 750 and 1000?

I did not fill the fuel filter after changing it.

SEADave wrote: I would suspect the CPS. I never changed mine under the recall, and a couple of times I have had phantom stalls.

That seems to be what the guys on the diesel forum are leaning towards. Strange to have it coincide though...

Stalling and then starting right back up just fine is precisely what a bad CPS causes. I've had it too.

Interesting. I didn't get and CELs, but it feels like the kind of behavior I would normally associate with a bad ignition part.

Remember, diesel is a whole different thing - once you are running and warmed up there really is no ignition per se. Check out this: http://www.guzzle7pt3.com/cps.php

When I got home I snatched the old CPS out and installed the one I had on hand. Figured I'd start there since it was a 5 min job and I had planned to do it anyway. Short answer, truck runs great!

The old sensor was very clearly not old, but was also very clearly not the real Motorcraft item like I was installing. The PO said something about another sensor that a shop had replaced about six months ago where they used a non-ford part that he had to replace with the real ford item because it didn't last too long. I bet this was done at the same time.

old-not-old on the left, new Ford on the right: