So I'm having some issues with my 7.3 that I'm really scratching my head about. I have surging, which at this point I am thinking might be the accelerator (gas pedal) sensor, it only seems to happen at specific speeds/conditions and a slight change with the accelerator pedal makes it go away. My two biggest concerns is that occasionally I will have a hard jolt, it feels like I hit the brake hard for a split second, and then it's fine. It doesn't happen often, but enough that I'd like to figure it out. The other issue is that sometimes the engine will just die for no apparent reason. No CEL (check engine light).

So here is what I have done to it - replaced ICP, replaced exhaust back pressure tube and sensor, replaced oil pressure sensor, replaced valve cover gaskets and injector/glow plug wiring harness, checked driver side wire harness over the valve cover (no wear, but I wrapped it with electrical tape anyway), rebuilt turbo last year (KC turbo balanced wheel kit), replaced the turbo vacuum lines (red/green plastic tubing). I've done a buzz check on the injectors and they all sound good. I've done a contribution test and no errors, but I just heard from someone that a tune might disable the contribution test?!? I have a DiabloSport tune to improve fuel economy (no tuner chip).

So if anyone out there has suggestions on what else I need to check, I'd greatly appreciate it!

Oh, and I do plan on doing the harpoon/hutch mods in the next month or so.

 

How old is the CPS?

To get more definitive answers, log PIDs and plug the numbers into the PID Charting Tool at the top of this forum so we can see what the engine is doing when this jolt occurs.

 

The problem is that it occurs very infrequently (the jolt), like maybe once every couple of months. I am going on a long trip this week, so I'll see if I can hook up my laptop and have FORscan running the entire time.

 

My first thought is a failing CPS, too.

 

Do you have an idea of when the jolt happens while driving? Is it in a locked or unlocked TC?

When it stalls, is it stopped or moving?

 

Could you give a little more detail on the issue? You say it feels like you hit the brakes hard, like emergency stop hard? What is happening with the engine when this happens, like RPM or do gauges flash or shutoff like a power loss? I assume you've checked the brakes for any broken or missing pieces. Greased the slide pins recently? Another thought, do you still have the factory exhaust back pressure valve in place? Any chance it's come unhooked from the actuator and flopping around, or perhaps the actuator has found a means of completing the circuit and occasionally shuts the EBPV, in turn shutting you down.

 

I figured I would report back on this issue. After a LOT more research and finally getting some useful Forscan data, it was pretty obvious that I needed to replace my IPR. After installing the new IPR, my engine starts quicker, runs smoother and quieter and I have not had a single instance of surging, bucking or stalling since. For what it's worth, I bought a International/Navistar T444E IPR instead of the Ford branded IPR. It's the exact same part, manufactured to the exact same specification (since the T444E and the 7.3 PowerStroke are the exact same engines), I guess Ford feels that slapping their name on the bag justifies selling the part for over $100 more.

 

Usually, the Navistar branded part is a lot higher than Ford, at the dealerships anyhow. Where did you find yours?

 

I got it from Diamond Diesel & Turbo.

 

So about 2 weeks ago my excursion stalled at a red light and I couldn't get it restarted. Fortunately I was headed down hill and there was a gas station right across the intersection, so I was able to coast and pick up enough speed to pull into the station and get to an out of the way corner of the parking area. I managed to get it restarted, but it was running bad again. Worried that maybe I got a bad IPR, I took a look and found that the nut that holds the IPR coil in place had loosened and come off, allowing the coil to move around. Fortunately the nut and spacer were in the valley right under the IPR, so I was able to get the coil secured back in place. Is it just me, or is that stamped nut a really poor solution for holding the coil in place on the IPR?

 

I've never had an issue with the nut. it's designed that way because it doesn't take much to hold and they don't want people over tightening it. it must not have been snugged up quite enough when installed. At least it was a simple fix.

 

If I recall it's a 5/8 thread. Just don't remember if it's fine or coarse. I want to say coarse but...

 

Crazy, this just happened to me yesterday in my 95 f350, died in an incline with 3 lane 5 a clock friday traffic and right in the middle lane lol, oddly enough there was a popo right behind me lol, my hazards didn't want to work for what ever reason (bad flasher relay) so the the cop turned his lights for safety, right after he got off his patrol unit the truck started, gave him a thumbs up and went to the nearest exit I could find. I thought for sure he was going to pull me over but he went his merry way.

After some second degree burns I managed to put the IPR nut and spacer back on.

 

It’s 1/2”-20 UNF.