Air/Fuel ratio gauge?

[TurboSevenThree]

Do those even work on a diesel?
If so, how would I wire one up? On a 2000 7.3. I don't even know if I have an O2 sensor.

[TurboSevenThree]

Nobody wants to help me? Does anybody know ??

[loki]

i have no idea but here is a bunb mabe the one of the techs chime in later

[Tikal]

You don't have an O2 sensor on a diesel. What you need is a pyrometer gauge...

Diesels are different than gas burners where a gas engine's air/fuel ratio shouldn't be too far off of 14.7:1 and diesel's air/fuel ratio varies depending on how hard of a load the engine has...

There's no perfect balance with air/fuel in a diesel engine. When you're idling, your air/fuel ratio could be 100:1 due to the engine injecting only a small amount of fuel, just enough to stay running and other times when you have your foot in it the ratio could be 5:1 or worse with black soot rolling out the exhaust.


Conclusion, no you don't need the air/fuel ratio. I'm not even sure it would work. I'm not familiarized with them enough to know how they hook up...

But my thinking is a pyrometer is to diesel what air/fuel meter is to gas!

[99SMOKR]

Originally Posted by Tikal

You don't have an O2 sensor on a diesel. What you need is a pyrometer gauge...

Diesels are different than gas burners where a gas engine's air/fuel ratio shouldn't be too far off of 14.7:1 and diesel's air/fuel ratio varies depending on how hard of a load the engine has...

There's no perfect balance with air/fuel in a diesel engine. When you're idling, your air/fuel ratio could be 100:1 due to the engine injecting only a small amount of fuel, just enough to stay running and other times when you have your foot in it the ratio could be 5:1 or worse with black soot rolling out the exhaust.


Conclusion, no you don't need the air/fuel ratio. I'm not even sure it would work. I'm not familiarized with them enough to know how they hook up...

But my thinking is a pyrometer is to diesel what air/fuel meter is to gas!

totally agree

[TurboSevenThree]

Well thank you for that enlightenment! I wasn't totally sure. I had thought it was exactly like that but like I said, I wasn't totally sure.

I thought the pyrometer measured EGT's, as in tempurature. But I got one of those, and boost, and tranny.

I wasn't thinking about how on gas engines the air and fuel are pre mixed, I guess I just assumed it could read the ratio once it mixed but that is the boomboom part! lol

Silly me!!!

[Tikal]

lol yea you've got a good point that I overlooked as well with the air/fuel premixed and the boomboom part.

The pyrometer does show you EGT's....but you CAN kinda use it to show how much fuel you're using.

Example: I'm driving to work. Most of the time on the highway @ 55mph, 2000rpm my EGTs are 450-500....
Now when I go across a hill or something, I can either push the pedal more to get up it faster, push the pedal more to maintain my speed or just kinda slouch a bit and lose some speed for sake of fuel economy....

I can kinda get an idea of how much more fuel I'm using goin' uphill than I was on the flat because the engine is working harder, burning more fuel to get up the hill, and that shows on the pyrometer depending on how much my pedal is crammed down


So in essence you can KINDA use a pyrometer to measure your air fuel ratio and/or, BECAUSE the hotter your EGTs are the more fuel the engine is pumping in to work

[TurboSevenThree]

That's what I figured. If the truck's running rich it's making more power, and therefore it'll get hotter. That does make sense, just like it cools down when you're idling - less fuel consumption and smaller boomboom

[99SMOKR]

exactly, whereas if you lean out a gas motor you run into some serious issues, richen it too much and it runs like ****

[Tikal]

I've seen a couple of ricers that run rich and they blow more black than my dually