Watching the news lately, no matter how unlikely, makes me think about a nuclear scenario in America. My understanding is that if a nuclear bomb was detonated, it would generate an EMP that would destroy the engine ECMs of all vehicles within a certain radius of the blast.

SO...thinking in terms of a bug-out vehicle, do the 7.3L trucks (thinking an Excursion, actually) require an ECM to run? Or assuming you could supply power to a lift pump and the starter manually, would the engine fire up and run? Is the throttle a mechanical connection?

I know I'm going a little crazy here, but I'm also curious. My current 2017 Super Duty is controlled by many computers. I know the 7.3L uses oil-operated mechanical fuel injectors, so I'm thinking it might work?

Thoughts?

 

Yes, they require the PCM to run.

Just stock up on weapons, ammo, food and water and create a plan for you and your loved ones.

We are not doomsday preppers by any stretch of the imagination. But, I have several weapons, several thousand rounds, food and water rations for months on hand. We live in the country though, and if there is a bad storm we may be without power for a while, so this is our main reason for stocking up on rations. The guns and ammo, well they are just fun and I have a range in my backyard.

 

Thanks for the reply. What does the PCM do on the 7.3L?

 

You need to think in terms of a 1975 truck.
Anything newer will have at lest an electronic ignition.

 

Diesels don't have an ignition system...

 

Everything. You can't run a 7.3L powerstroke without one.

The 7.3L IDI (pre-94) was a mechanical diesel but I don't know if it would EMP-tolerant or not.

Any *gas* powered truck since the 70's will have an electronic ignition system.

 

That stuff's not all leftover from the Y2K thing is it? You should have seen all the freeze dried food and generators I delivered back then.

 

Not even close. We replenish our stock every few years even though it can keep for much longer. Generator gets run up about once a quarter.

 

The nuclear fallout will kill you long before your supplies run out. Even if you survive the nuke portion of the end of the world, not much will be left after your supplies run out. City folk will scamper for the country, devouring everything in sight like a swarm of locusts.

 

I'm not trying to turn this into a thread of about doomsday. Several folks are telling me a 7.3L will not run without a PCM, but I haven't gotten a straight answer as to why not.

For example, my 2013 Kubota tractor has no computers. Just a battery, an alternator, a starter, instrument panel, and lights. When it cranks over, the high pressure engine-driven fuel pump supplies fuel pressure to the injectors. When pressure hits a certain point, they pop open, fuel is sprayed, then the injectors close and pressure is relieved. The compression heat ignites the fuel after air is drawn in. Diesel 101.

So thinking further, I realize any common rail diesel is not going to work because the injectors are electronically fired.

But the 7.3 (and even the 6.0L and maybe the 6.4L) use oil pressure, and a separate high pressure oil pump, to pop the injectors open and closed based upon timing of the pump, which is also engine driven.

So I know the 6.0L uses HEUI (hydraulic electronic unit injectors) and since the word electronic is there, the 6.0L and newer is out. But is the 7.3L also operated by HEUI or simply HUI?

I realize a modern vehicle like a 7.3L Excursion has many other computers and ECU's to run windows, seats, climate controls, audio, headlights, you name it. I was just wondering *at its core* if the engine could be run strictly by getting it started.

 

The quote below is from the Excursion Bug Out Vehicle thread from a few years ago. https://www.ford-trucks.com/forums/1...l#post14120818

Stewart

 

Stewart...very helpful. Thanks. I've done a little bit more reading and I've been putting the cart before the horse it seems. From what I've read, *some* vehicles will likely be affected, but most won't. I can also corroborate what you say about the "antenna effect" which vehicles don't really have.

That leads to a second question...will the aluminum body of my current Ford protect as well, better, or worse than a steel-bodied vehicle?

 

Because the injectors are not fired by the high pressure pump. They are electronically controlled by the computer. If the computer doesn't tell the injectors to operate, they will just sit there and no fuel will go into the cylinders.

That's the way the pre-Powerstroke 7.3L IDI engine worked. The last of those in a Ford truck was 1994.

The 7.3L Powerstroke, introduced in mid-1994, is HEUI. Without a computer to tell the injectors when to open there is no fuel injected.
No, that capability went away at the end of the 1994 model year in a Ford diesel.

 

Thanks Mark. Makes sense now.

 

Taking the EMP thing to where it's more likely - it won't be a nuke... it will be the mother of all solar flares. It will happen for sure, but like the Cascadian fault giving way to make a 9.0 earthquake in the PNW, we don't know when it will happen.