Hi John,

I really can appreciate your last line of communication.
“Thanks to all who have helped me so far... I am learning a great deal through all of this but mostly I'm learning how much I don't know!”

Isn’t that and always the case with the amount of X factors mixed in with our imaginations.
If there is a boundary of knowledge or having a boundary defined in the cosmos even, we would then ask, what’s beyond that?
I have written some off to what “we think know” being very limited and the facts that there’s the present and there’s infinity in the equation.

Luckily we only have to deal with those things we made to the best of our abilities of which occasionally last longer than other items.
We have this dilemma with our self imposed confinements (money) and limitations driven by survival need’s first. After that it’s about keeping life interesting enough to fix things we can.
Here is where us fix- it types dwell. 🤫

You did mention the EGR so this engine has one I assume?
What year engine is it?
The soot is still appearing on the spark and that fact is talking to us?
Could be that there is excess air entering but not the fresh stuff?

If the engine is prior to the 1989 and without the newer fuel management system you might have an issue with the coolant temperature sensor being not compatible with the ECU. The mechanics of the engine remained pretty much the same as usual and as far as I know useable.

I think there are different color ones from the eighties to ninety cars with EKZ or EZK system. Slightly different ways to obtain timing and controlling spark but the basics are equal.

This sensor change might explain it running to rich.
It’s not winter time OR could it be a bad one OR a wiring issue so I can see why you are leaning one ear up and one ear down … thinking. 🤔
Also, I think it “might” be possible that the throttle switch connector can be crossed. I have only read about it by some posters but have never investigated it.
I have a problem with it reaching to each one let alone with the pins inside being three versus two.
Maybe it’s the knock sensor or instrument gauge wiring to be looked into.
I had better stop thinking on those possibilities without more knowledge myself.
So you are not a first person to go down that road looking for answers. 😊

The EGR also has a controller on the strut tower.
I have discussed in other threads about their arrangement and how the valve has to vent the vacuum line to turn off.
The little piece of foam rubber rots. It’s the filter on top under a cap that gets plugged. I replaced it with polyester fiber fill but it still gets dirty over the years. I’d say about every ten has been my experience but at least pieces don’t get down inside it. I washed it out with denatured alcohol. No more EGR/ CEL lights.
BUT … you are not getting either lights or codes but the ECU looks for a temperature change.

It must be getting a signal back from the body of the EGR within the time limits of the program?

As far as checking the EGR for it to be sealing off the exhaust port, I have never ever had to mess with mine but if you took a connection loose or off, would think it shouldn’t pass air into the engine as it is pulled open with vacuum.
These engines run rather clean anyways.
The oxygen sensor arrangement double checks that.
So the issue of engine maintenance isn’t as bad as the first smog engines.
Those had them directly under a carburetor onto a flat aluminum plate.
It in turn got eaten away by exhaust gases and caused very rough idling.
That item got tossed out of my old Ford 100 before inspections along with its vapor canister that filled up with water from the right front tire spray.
The truck only came with a 12,000 mile warranty so it was easy for them to wait me out!
I did, no more Fords or new vehicles ever again.
Shopping for better designs and “used” comes with some debugging already.
It was a pitiful 1974-5 saga for Ford’s products in these times.
The gas embargo years really put our American shorts in the wringer that still get bunched up.😬

I’m glad to know that you are giving the 240s the respect they deserve.

I’m still having to think on why you have white smoke? Blue, black and white are indicators.
There some contradictions here in the assessment.

Are you sure it’s not water vapor? Incoming air has humidity and therefore water vapor.
Does anything condense on your hand or can you smell the monoxide in abundance when it running?
Incomplete combustion varies the amounts because of the lack of heat to thin it all out.
Apparently it is starting to run long enough to get into an operating zone but is it warm enough to be read correctly to the ECU.
So it’s back to coolant temperature in my mind.
An accurate 92 degrees centigrade thermostat is best IMO.
I think the fuel pressure is on target for the injection cones.
The cylinder heating and air content is affecting all the cylinders.
Your one cylinder doesn’t appear to be all that under specification considering it’s a cranking gauge test. They do request only a 10% differential in an ideal world.
There’s lots of engines running just fine if the ECU can determine its signals are righteous. The system is designed to be self tuning very quickly.

What number OR heat range spark plugs are you running?
I think you stated the gaps set on .65 mm that is a little tight when .028 is my preferred. So .71mm is closer but not much more or it goes the other way.
These engines do best without any fancy tipped and expensive plugs.
Bosch silver or super name.
I think the set is Bosch 7900 and has a copper or nickel or both plated for an electrode.
It depends on how much description a vendor puts in the page.
In stainless steel nickel is for heat resistance and chromium for its rust resistance quality.
Henry Ford made it a more popular product to replace chrome plated trim that has gone to a vapor coated plastic.
A limitation on what we build or use = $$.

Plugs were made to be inexpensive by design and haven’t changed as much as they want to you to buy into.
Auto store Spark plugs are similar to French fries of fast food chains.
$2.50 to 3.50 for a potato?
Certain ones and brands for some cars have become overly profitable to a naive customers.
RA shows ours to be $2.12 each of which is about right for a lawnmower too.
In the seventies it costs $.25 to make a plug out the factory door to any manufacturer, packagers and on to other wholesalers.
It is probably automated and faster today, so a $1 tops and in flats like eggs.

I hope this chatter can give you more to ponder over and provide encouragement to keep at it!
You can learn what ever you really desire to learn.
😊
Phil