pump raising question

[creighta]

Thinking about turning up my pump.

I have read that this causes high EGT but conventional wisdom on gass engines is that fuel actually helps cool the engine some. What is it about the diesel that causes higher temps?

Also. Every semi I see running and every farm tractor we have ever had blows black smoke for short periods when taking off or down shifting under load. My truck has never done that, so does it meen that I am currently underfueled?

 

[creighta]

Any thoughts?

 

[Brutis]

It's definitely best to have a pyrometer installed before turning up the fuel. Its easy to start melting pistons with too much egt. Having said that, continuous black smoke would probably indicate a problem (i.e. too much egt), whereas brief smoke under heavy acceleration that cleans up after a second or two might be acceptable. Do you have a turbo on your truck?

 

[plywood]

The old rock hauling dump trucks that puked some black smoke between gears were running low compression and high boost.

Can you say, "before any diesel emissions laws"

The black smoke was from "dropping the hammer" and giving full fuel before the turbo caught up and gave it enough air to burn the fuel you saw as smoke.

 

[1994IDI]

If you fill in your sig it will give us a little more idea of what you're working with and allow us to give you better advice.

I am no expert on diesels, and someone correct me if I'm wrong. I believe the high EGT's stem from the high compresssion and higher amount of energy diesel fuel puts off when it is burned. (Again, apologies if I'm wrong.) But there is no question that increasing the flow on your IP will increase your EGT's and will no way, cool your engine. A pyrometer is the only way to stay on the safe side as opposed to guessing when your pistons are going to melt.

I don't know if there is a way to tell if you are underfueled. The best way to go, is to install a pyrometer, then experiment with your fuel setting until you find a happy harmony between power, fuel economy, and EGT's. Then you will no for sure because the pyro will allow you to see what's going on in your engine as opposed to trying to guess if you have to much or to little smoke. Hope it helps.

 

[creighta]

definitely not planning on turning it up till I have a pyro in. was going to be this month, but two batteries and an alternator had to come first

I though I had my sig updated a while back, guess it didn't save. I'll have to try again.

thanks for the replies all.