Diesels run lean, the leaner they are the cooler they will run and the more your engine will love you. Smoke ratio is approx 18:1, so around 22:1 a/f ratio at maximum load is good.
As load decreases air fuel ratio can go well over 100:1 - absolutely nothing to worry about.
Some modern computer controlled diesels do control a/f ratio as part of the emission system.
Too much fuel or not enough air!
Altitude/elevation reduces air quantity - turbos increase the atmospheric pressure by a ratio, so as the barometric/atmospheric pressure drops, the boost pressure will also fall. Compressor maps for turbos give pressure ratio on the vertical axis - boost pressure is atmospheric pressure times pressure ratio minus atm pressure.
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What are the engine revs after it kicks back to second?
3000
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Do you know what your boost pressure is before/after it kicks back?
No I don't run a boost gauge
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Hoses have been known restrict air flow due to damage that is not apparent with an external visual examination.
Oil accumulation in inter cooler can also restrict air.
Hoses are probably 2 year old they are silicone.....and last time we had the hoses off there was only a very very small amount in the end of the hose like a dusty light covering
I find that really hard to take seriously!
Smoke is not due to egt, but egt will be increased if you have black smoke with your right foot down.
Black smoke is incomplete combustion of fuel. Nearly always due to enough air to burn the fuel, but could be due to poor atomisation from a faulty injector (but 300Tdi's don't have many injector problems).
Tweaking the pump can involve up to 4 adjustments.
Some smoke can be tolerable, as long as it clears reasonably quickly (when boost pressure increases).
To get boost to build sooner, more fuel is required - the turbine needs the exhaust gasses to drive the compressor.
One adjustment, the torx screw adjustment in the top of the boost compensator adjusts fuel when there is no boost - screwing this down gives more fuel to help get the turbo going.
The screw under the spring below the diaphragm in the boost compensator will increase/decrease fuel quantity as the boost pressure increases.
Rotating the conical fuel pin is used to adjust fuel rate at maximum boost pressure. But will increase/decrease fuel across the full range (zero to max boost).
Most instructions I see give adjustment procedures in the order I have above. But IMHO it is back to front - rotate fuel pin 1st, then adjust spring pressure if required, then the torx screw.
The 4th adjustment is the maximum fuel rate screw on the rear of the pump - unless you have an upgraded turbo you shouldn't normally need to adjust this.
The purpose of the boost compensator is to reduce fuel when the boost pressure drops.
High egt is bad for the engine - piston melting etc.
Increased boost pressure will increase air quantity and lower egt.
The increased performance which comes with boost presure will result in an insignificant increase in stress of engine - this is due to the part of the cycle when it occurs. The majority of stress is due to inertial loads due to reversing the direction of the reciprocating parts. The inertial loads increase with engine revs - power increase from turbo does not increase revs.
