The first fault case is that it is difficult to start after replacing the timing belt during the grand maintenance of Guosan Iveco, and there is a fault code.
The first fault case is that it is difficult to start after replacing the timing belt during the grand maintenance of Guosan Iveco, and there is a fault code.
Iveco’s short head design seems inconvenient to maintain, but it’s not. When Iveco carries out engine maintenance, it only needs to remove the headlamp assemblies on both sides.
There are four bolts in the connection of the central grid on both sides of the vehicle body, which is very convenient for disassembly. After all the four bolts on the left and right of the bumper are removed, the whole engine room can be exposed.
Due to the air conditioning evaporator installed above Iveco’s engine, it is inconvenient to disassemble the upper housing of the timing belt. The repairman is lazy and draws a position mark on the camshaft pulley and cylinder head respectively. At this time, the crankshaft timing mark point is in the vertical downward position.
Since the number of belt teeth in the accessory box (oil pump) of Guosan SOFIM Iveco engine does not have a multiple relationship with the number of crankshaft belt teeth, it is not necessary to consider the timing position. After recording the marked points, remove the timing belt, timing belt idler and tensioner, and replace the bearing.
It is difficult to start after all are installed. It takes more than a dozen compression before there are signs of vehicle. The fault code is shown in the figure. After clearing, Iveco the dynamic non true current fault of the engine drag torque control system reappears.
It is concluded that the position signals of the crankshaft and camshaft are not synchronized, so it is impossible to accurately judge the cylinder. Recall a detail in the disassembly process to attract attention.
During the assembly process, first install the No. 2 tensioning pulley. The belt bypasses the No. 3 camshaft pulley, No. 2 tensioning pulley, No. 1 crankshaft pulley and No. 5 accessory box pulley in turn. The timing belt idler pulley is finally assembled together with the support. Due to the tension of the tensioning pulley, the coordination of the whole gear train is relatively tight.
After the repairman installs a bolt on the idler pulley support, insert the screwdriver into the idler pulley support and the bolt hole of the cylinder block to pry and twist the support, In order to install the second bolt, finally pull out the screwdriver and install the third idler bracket bolt.
In the process of prying the timing belt idler, the idler exerts a pressure on the timing belt, resulting in the stretching of the belt on the left side of the gear train Iveco, and the deflection of the crankshaft and camshaft in the opposite direction. Finally, the position signals of the crankshaft and camshaft cannot be synchronized and a fault code appears.
Although the way of manually marking the position is seriously not in accordance with the standard maintenance, it does not lead to the situation that the position signal cannot be synchronized. The root cause is to forcibly pry the installation of the idler support Iveco. Install the idler support in advance, roll the belt, and then push the idler onto the shaft of the support to avoid timing offset.
For example, Iveco is difficult to install the belt tension during the installation of the idler, Pry the compression tensioner and turn the crankshaft counterclockwise at a small angle.
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