Doosan 80 can be called a small tonnage excavator with super high cost performance ratio. It is also because the purchase price is fair, the failure rate is not too high, and the maintenance cost is within the acceptable range, so it has become a new star sought after by everyone
A boss bought a second-hand Doosan 80 small excavator, but unfortunately, after two weeks of work, the machine had trouble starting, weak engine and black smoke. Let's take a look at the tortuous way to solve the fault of the machine!
Fault phenomenon:
When it comes to the fault phenomenon, the owner seems to have a lot of bitterness to talk about. When he bought the second mobile phone, there was no problem with how to test and check it. However, less than two weeks after the construction, it began to have trouble starting and unable to emit black smoke
Unexpectedly, the local maintenance novice also took a swipe at the owner. The maintenance worker categorically said that the fault point was in the fuel injection nozzle and the fuel injection pump, and that the pump needed to be adjusted. After the adjustment, it was found that the exhaust pipe was emitting white smoke, which could not be hit at all!
Failure analysis of Doosan 80 engine weak, black smoke and difficult to start:
First of all, according to the owner's recollection, the local maintenance master found that the fuel injection volume of each cylinder was uneven when adjusting the fuel injection pump, so he adjusted it according to the routine until the fuel can be supplied evenly
Then it was found that the injection pressure was insufficient and low, so it was adjusted accordingly, but the normal operation and adjustment made the machine simply unable to start! Let's look down together
Troubleshooting of Doosan 80 engine with weak black smoke and difficult starting
After the maintenance engineer arrived at the site, he made a preliminary judgment. Because the fuel injection pump had been marked when it was disassembled, the analysis that the fuel injection pump could not be started due to misalignment and poor adjustment can be eliminated first
Next, the maintenance master focused on whether the plunger of the fuel injection pump was replaced in time and whether the oil outlet valve was jammed, because when adjusting the fuel injection pump, the fuel supply of each cylinder was adjusted to be uniform, but the fuel injection nozzle was replaced again, and the pressure was adjusted again
If the plunger is not replaced in time or is seriously worn, and the closing effect of the oil outlet valve is not tight, the oil pressure will not meet our expectations after adjustment, so there will be white smoke in the exhaust pipe due to the lag of injection, or even it will not start at all
In order to confirm this speculation, the maintenance master replaced the plunger and outlet valve of the fuel injection pump, and adjusted the pressure of the fuel injector to the standard pressure. After one successful start, the engine started back to normal. So far, all the fault points have been removed
summary
As the saying goes, it is easier to look at flowers than to embroider flowers. The same is true for excavator maintenance. A small difference in maintenance techniques may lead to many unnecessary failures instead of being repaired!
