Combines cr 970 low on power

JHEnt

Guest
First you need to determine f you really have a power shortage or if a configuration change of the machine will free up more power. Depending on what you are running different concaves or combination of concave wire spacing can make a difference. If you're sure the engine seems low on power then you need to look at the simple things first. Too often with electronics everyone wants to look there 1st. I've done that myself. Start by checking the fuel delivery pressure from the electric lift pump, both with engine not running and runing at full speed. If the delivery pressure is low the engine will not have full power. Check the fuel filter at the tank next to the electric pump. Also there could be plastic shavings in the fuel tank cutting down the fuel draining from the tank. Plastic shavings left inside from manufacture_machining has been a reoccuring trouble since tractors first started using them. Other companies machines have had the same problems. Assuming fuel supply to the engine is correct then the problem may be electronic induced. There are a number of factors that will affect fuel rates on these engines. Air boost temperature and boost air pressure both affect the fuel rates allowed. For instance if the boost pressure reads low or on the IVECO too high the fuel metering is decreased to match conditions. EX bost pressure is low for the short time when the engine is revved up. Untill pressure fully builds the fuel is metered lower to keep emissions down. Once boost pressure builds then the full fuel rate is applied. It works the same as the anernoid mechanism on mechanical injection pumps. Other conditions in the field can cause a fuel derate. These can really only be indentified if you know what to watch while you're runing or by having the dealer laptop hooked up while combining. Things that cause "derate" include when the boost pressure goes too high, when engine coolant temp gets too high. I don't remember all of the specifics for the 10.3l IVECO that is on the CR970 but NH has a list of functions to check for complains of low engine power.
 

cr970_2

Guest
air boost temp is a big factor affecting fuel rate try unpluging the air temp sensor seems to help also you can add a resistor to fool the sensor to think air temp is cooler gained 7-8 pounds of boost
 

JHEnt

Guest
The air temp won't matter if you go over the max boost pressure the engine will go into a derate mode. The 7.5l Basildon engine (Bosche fuel system) on the CR940 does not do this but the IVECO engines both (7.8 and 10.3l) will.
 
 
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