Improper Maintenance of VE Injection Pumps Cause Problems

Fault phenomenon: Diesel engine on an Iveco 40.10 car was assembled with VE distributor fuel injection pump. The plunger of head rotor was badly worn. So, the engine has difficulty for starting. Then change the head rotor and cam disc which has been worn seriously. However, diesel engine cannot start when the correction of the fuel injection pump was loaded to the car after being revised.

 

Troubleshooting: After checking, there is no air in low pressure oil pipe. Oil supply solenoid valve is normal. While using the starter to drive diesel engine crankshaft rotate, fuel injection pump can supply oil. But starting again, the engine cannot start any more. Then it’s thought that the angular advance of fuel injection pump is too small. So loose the nut which fixes the injection pump. Make the pump cover rotate to the end toward the direction of increasing fuel supply(increasing the angular advance of fuel supply to the largest).The diesel engine can barely start, but exhaust pipe discharges a lot of black smoke.

 

Remove the fuel injection pump from the vehicle, checking and adjusting again. When check the fuel pump after being fuel injection pump, it’s found that the new changed cam disk is different from the old one.

 

Some of diesel engines used in Iveco car are low emission engines which discharges less pollutant (such as 8140.47 type diesel engine). The injection pump matched with the engine is also improved. For cam disc on two kinds of fuel injection pump, in addition to different carved code number (the code number in the general diesel engine is DE604, and low emission diesel engine CAM plate, code-named DE640), the raised height of cam disc is also different (the raised height of cam disk of general diesel engine is lower than the cam disk of low emission diesel engine by 0.3mm).In addition, the length and shape of convex surface of cam plate also have differences.

 

The fault cause: In VE distribution fuel injection pump, the drive shaft of fuel injection pump drives the cam disc through connector. Cam disc is equipped with drive pin to drive the fuel injection pump plunger rotate. The convex surface of cam plate is the same as the number of diesel engine’s cylinder. When the diesel engine is working, under the joint action of cam disc and the spring of plunger, fuel injection pump plunger either do reciprocating motion according to the specified lifting of cam plate’s convex surface, or do the rotation driven by the cam disc. Therefore, the convex surface’s size and shape of cam plate will affect the fuel advance angle and law of fuel injection of fuel injection pump.

Due to change the wrong cam plate, angular advance of fuel injection pump lag behind. Oil supply rate changes over time (or crankshaft angle). So diesel engine cannot start or rotate normally. Even if the fuel supply advance angle of fuel injection pump will be dispatched to the maximum, the diesel engine can start, but exhaust pipe of diesel engine discharge a large amount of black smoke during operation, which is still in the abnormal working state.

 

Troubleshooting: Replace one set of cam disk code named DE640 to fuel injection pump. Installing the machine to the car after correction, the diesel engine starts easily. The phenomenon of exhaust pipe discharging black smoke has been eliminated.