Running the motor lean hurt it?

turboman1

turboman1

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Can running a diesel motor lean hurt internal parts?

I know at idle they can run as much as 60:1 (60 parts air to 1 part fuel) and at full throttle they can run 20:1.

So what happens if the motor gets too much air can that hurt it? High egts or low egts?

Thanks
Adam
 
Getting to much air in to a diesel would be a large feat to accomplish. The more air you bring in the cooler the egt's and the more fuel that is burned.
 
Not that I know of.

Would be very interested to hear an explanation of how it could hurt anything from someone who thinks it could though!
 
Diesels run with an abundance of air, its not regulated. The engine speed is regulated by fuel supplied. A lack of fuel results in a lack of rpm or power. Take away fuel and the engine will slow down. A cylinder with a lack of fuel will run cooler EGTs than the others.

There is no such this as running a diesel lean.
 
I found this from a website... Diesel-Central.com the technical source for Diesel Truck information, Truck Pulling, and Drag Racing

In a diesel engine, the combustion chamber is always full of pure air before the fuel is injected. When the engine is idling under load, a very tiny amount of fuel is injected. When working hard, say while pulling a big load, a lot of fuel (relatively) is injected. Because the amount (weight) of air in the combustion chamber is relatively constant (I'm not considering boost here...) and the amount of fuel is variable, diesel engines run at varying air/fuel ratios. At idle, with no load, it is not uncommon to have a diesel engine running at an air/fuel ratio of 60 or 100:1. Under full power, most diesel engines need to run lean of stoichiometric. (BTW: the stoichiometric ratio for diesel fuel is NOT 14.7:1 and it varies slightly depending upon the composition of the fuel.)

For a number of reasons, most diesel engines will emit visible hydrocarbons (i.e.: smoke) if run near or over their stoichiometric fuel ratio. Diesel engines thus always need to be run lean of stoichiometric.

So of course underfull throttle a nice haze will be close to whatever air to fuel ratio satisfies a diesels needs... but any other time it sounds like a diesel is running lean unless smoking like a frieght train.

So if you get a diesel to lean it will start smoking white smoke right? Nothing other than possible not having enough fuel to create a spark making the engine miss would hurt the motor then right?

Thanks for the replies

Adam M.
 
I don't think that "too lean" would automatically cause white smoke as long as combustion temperatures were high enough.

Cold engines smoke white, and engines burning antifreeze smoke white, that's more due to low combustion temperatures than stoichiometry.
 
You can run a diesel too lean. I'll give you a few examples, but I'll let y'all guess why first.
 
If you run a diesel lean on the bottle you will see some plasma torch EGT's......like 2K!
 
We have a stoichiometric window ten thousand times more forgiving than a gas engine and you guys STILL manage to screw it up? LOL
 
Mine runs too lean and dies every time I shut the key off, imagine that! :hehe:
 
joefarmer said:
You can run a diesel too lean. I'll give you a few examples, but I'll let y'all guess why first.
Click to expand...

I have seen the 7.3 powerstrokes with tunes that make them sound like cammed out drag cars with crazy lopy idles and they smoke white, but i think that would be more from timing.

I do not know why please fill me in

thanks
Adam
 
I believe greg was explaining this too me at TS, but I dont remember enough to explain it!
 
I just jumped injector sizes and lost about 125-150 degrees with a nice power gain, now EGT's are really over rated.

Jim
 
A buddy of mine got on the nitrous button a little too soon and she died...so YES you can get a diesel too lean!
 
XTrEmE9156 said:
no such thing as diesel too lean..
Click to expand...
:hehe:
joefarmer said:
You can run a diesel too lean. I'll give you a few examples, but I'll let y'all guess why first.
Click to expand...
:rockwoot::bow:
Jim Fulmer said:
If you run a diesel lean on the bottle you will see some plasma torch EGT's......like 2K!
Click to expand...
*nx*:doh:
Begle1 said:
We have a stoichiometric window ten thousand times more forgiving than a gas engine and you guys STILL manage to screw it up? LOL
Click to expand...
:doh::doh::doh: proper use of the:owned: myself here:what:


Me example of running a diesel too lean.
Snow wjite carnage II
 
Ever use a cutting torch? Get a piece of metal really hot and then add a bunch of oxygen.

Paul
 
joefarmer said:
You can run a diesel too lean. I'll give you a few examples, but I'll let y'all guess why first.
Click to expand...
Here one example is:doh:
Flamesmallcopy.jpg
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