New Holland CX720 Repair Manual page 1801

ENGINE - Troubleshooting (B.10.A - G.40.A.10)
CX860, CX880
NOTE: Preliminary conditions
Electric troubleshooting has to have been performed with specific instruments.
The air system must be efficient.
The engine must have the proper oil pressure.
If the engine works but has occasional or non-constant trouble, check the earth connections on connector B of the
control unit PIN 1 and PIN 2.
Problem
THE ENGINE FAILS TO
START
ENGINE STOPS
POOR ENGINE
PERFORMANCE
(LOW POWER,
CONSUMPTION TOO
HIGH, NOISY)
POWER PRODUCTION - ENGINE
Possible Cause
Batteries:
Low charge
Connections to terminals not efficient
Starter motor:
Not efficient
Heater:
Not efficient
Main relay
Not efficient
Fuse
Fuel supply pump
Fails to prime (incoming air)
Fuel circuit
Not correctly filled (air in the circuit)
Fuel filter and pre-filter
Clogged<
Fuel tank
No diesel
Mesh filter Pre-filter Fuel filter
Clogged
Trouble with fuel circuit
See POOR ENGINE PERFORMANCE
Speed
Idling speed too low
Main relay
Broken down
Fuel circuit
Mesh filter on tank clogged
Fuel pre-filter clogged
Fuel filter clogged
Air in circuit
Valve 0.8 bars on fuel return from cylinder
head:
a) Jammed open (low pressure)
b) Jammed shut (high temperature)
Bad fuel leakage
Supply pump broken (seized, broken cou-
pling, pressure adjustment valve, etc.)
Injectors
Irregular operation
Diesel leakage from O-rings
Air supply to engine
Air filtration (constriction clogged filter)
B.10.A / 255
Recharge
Clean, check, tighten the terminals or re-
place them
Check or replace
Check supply and earth connection. Re-
place.
Check heater relay perform active diagno-
sis
Check, replace
Replace
Check seal on intake branch. Check pres-
sure on filter inlet.
Check seal
Bleed
Replace
Refuel and bleed circuit
Clean, replace
See POOR ENGINE PERFORMANCE
Adjust
Replace
Clean
Replace
Replace
Check intake seals (quick couplings when
hot)
Replace
Replace
Check, repair
Check pressure on filter inlet Replace
Replace
Check for fuel in the engine
Check cartridge clogging indicator. Elimi-
nate constriction Replace filter
2 4/7/2006
Correction