Well my 7.3 don't really like the cold weather up her in the cold north.
It seems to take forever to get up to working temp. The temp gauge don't go past 1/4. I was told this is some what normal for these engines.
But the main problem for me is the regen/idle up function. No matter how long I drive or run the engine, if I put it in park for more then 2 minutes it idles up and stays there until I touch the brake, throttle or put it in gear.
In my mind I have concluded that there might be a faulty temp sensor and maybe the termostat is stuck open, but my mind is wrong most of the time Any thoughts?

 

Thought:

The factory gauges are not very good. Get a way to monitor actual tenpatures.
The trans temp is notoriously bad. It will sit on 1/2 right up to the point of your trans burning up.

You can get a few different apps that use a blue tooth dongle and display all the temps on a mobile device.

 

I have had it hocked up to two different Bluetooth obdII dongles and they both read -40 degrees for coolant temp. This was eBay dongles together with the torque app. Not sure if it's the app, the dongle or the 7.3's temp sensor. As I get a reading at the gauge cluster, makes believe that there either are two sensors, one for the gauge and one for the computer, or the sensor is OK. But the idle up function still goes all crazy at idle, and I don't think it should act that way when the engine reaches the correct temperature

 

Is your EBPV intact or has it been gutted/removed? That helps with engine warm-up quite a bit in colder temperatures.

Next... the factory gauge is kind of worthless if you want to know the exact temp. The easiest way to get an accurate reading is to use an infrared thermometer. They are less than $20 on amazon and insanely useful. The gauge and the computer use two separate senders.

Last, there is no such thing as a regen on a 7.3L. The idle should remain steady, so you have something going on that's causing that behavior. I don't think it's normal for the idle to go up after idling for 2 mins. Has the truck ever been tuned?

 

You will not see coolant temp thru the pcm. Look at engine oil temp.

 

Strange, tapping the brakes or throttle makes the rpm go back to normal, but I see now that the information I read was for the 6.4.

Do you know where the sender for the computer is located?

EBPV is intact and functioning

 

The ebpv closing will make it idle high. Hitting the brake cancels it. Someone else can explain it better. I removed it

 

Idling up in the cold is a normal function. Mine does it all the time. Runs for a few minutes and then idles up. Tap on the brakes and back to normal. Does it with or without the chip.

 

It should stop "idling up" once the engine reaches a certain temperature. I can't remember what that is off the top of my head, but I can look it up when I get home in a couple of hours. The computer measures oil temp and outside air temp (thermostat is in the intake air box), and decides whether the truck needs help warming up or not. I have removed my EBP as well, and my truck still idles up when it is below 40* F outside. I touch the brake or throttle, and it goes back to normal idle.

Since you live in the great white north, Thorvald, you might need to put some kind of air dam on the front of your truck to block the air from coming in on the radiator. I don't know how cold it is there right now, but many guys here in far north America have to block the wind from their radiators in the winter or the truck cannot get up to operating temperature. It is possible your thermostat is malfunctioning and not letting the truck warm up. Maybe stuck open...

 

Thank you all! I will try and get hold of another scan tool today, and read the oil temp. I don't really trust that eBay dongle at all. I think it has something with the engine not reaching the correct temp or the sender not reading it correctly. I did contact the previous owner after my last post, and it seems like it has a SCT economy tune. But that should have nothing to do with the idle up/temp problem. I would appreciate the info on the idle up temp if it's not to much trouble.
We are down to 27 F up here at the moment, but we do see 18 F at night

 

Then I have had it hooked up to a scantool, and after a longer run, the engine oil temp only reads 149* F when it reaches the usual spot on the coolent temp gauge.
It will never go beyond that point on the gage.

 

I found the info:

 

Get this book if you own a 7.3l Excursion. Make sure you get the correct year.

 

Thank you so much! That helped a lot making me understand how it functions! And I'm now sure that my engine is running to cold. But how in the world do I fix it....
I will begin with a winter cover, followed by a termostat and sensor change.

 

Happy to help out. The cover I linked to on Amazon above is just an example and NOT the right one for your truck. You will have to search a little for the right one.