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Correlation Between EGT's & Smoke?

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Driving Cross Country-Got Some ?s

Won't start, Fuel Shut off Solenoid?

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Is there a direct correlation between high EGT's and a lot of smoke? Can a normally functioning CTD have no smoke and still have unsafe EGT's?
 
Black fuel smoke is formed in a couple of ways. If the truck gets too much fuel before the turbo starts delivering enough air an over rich condition will result in smoke. This is a momentary problem and shouldn't last long enough to push egt's to dangerous levels. Modified trucks with fueling boxes, injectors, etc. will often have excess fuel delivered resulting in smoke under hard acceleration. That can result in too high EGT's.



Generally, a stock truck will run lean enough to not have too high EGT's. If there is some engine abnormality I suppose it could happen, but in our wonderful world of computer controlled engines the stock computer tends to keep the engines safe.



Some fueling/timing boxes will not produce noticeable smoke yet can still make excessive EGT's if puling a big load, especially on hot days. Best idea is if you plan to do any performance mods is to install the guages first.
 
I believe you could with a manual trans if you held too high of a gear for too long. Especially with a huge stock turbo housing on the early intercooled trucks. Otherwise, probably not.

Travis. .
 
Thanks for the responses guys.



What about a truck with a slightly turned up pump (ie. the mods in my sig). Is it safe to assume no or very little smoke means EGT's should be safe?



I have an EGT gauge and all, but am just curious since this is my first diesel and I'm trying to better understand how they operate. My truck has never really smoked hard. It used to puff out a decent amount under WOT just before the turbo spooled, but that is very minimal now that I backed the smoke screw out to 1/2 turn in from stock. Under WOT it still doesn't smoke and my EGT's seem to max out around 1200-1250 (pre-turbo). I'm just wondering if I have some more room to tweak the fuel screw without affecting EGT's too badly?
 
Changing my exhaust housing made a huge difference in my EGT vs speed on hills. I have more useable power with very controlable EGTs.

Travis. .
 
TKingsbury said:
Changing my exhaust housing made a huge difference in my EGT vs speed on hills. I have more useable power with very controlable EGTs.

Travis. .



Do you have a wastegated or non-wastegated 14cm housing? I just noticed Piers sells a 14cm non-WG for pretty cheap. Will the lack of a WG cause problems for me? I definitely don't want to worry about damaging something.
 
EGT vs Temp

I have had several of these trucks, in various stages of fuel system health and pump tuning. I had a late 91 that would roll the coal, and never hit 900 post turbo (about 1250 pre- 18psi boost). Had another (93) that would hit 1350* with little to no smoke- 19psi. oth had stock turbos and near or stock fuelling. Point is, while making billowing clouds of smoke can likely raise your EGT, (esp if your turbo wont spool with the fuel), a lack of it doesnt necessarily mean you are safe. But, I'd say with a stock or near stock truck, below 4000ft, you should be safe with AFC tweaks, ASSUMINg your pump and injectors are up to snuff. If either fall outside spec, all bets are off.



Stepping down off my soapbox,

Daniel
 
JRussell3176 said:
Do you have a wastegated or non-wastegated 14cm housing? I just noticed Piers sells a 14cm non-WG for pretty cheap. Will the lack of a WG cause problems for me? I definitely don't want to worry about damaging something.

Mine is a waste gate unit, but I don't have it hooked up so the wastegate is slammed closed. It works very good, and I'm not making enough boost to warrant a wastegate just yet (24psi).

Travis. .
 
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