Hello guys, I have a Caterpillar 320DL, the machine ran and started very well when cold (after rest), but after working for hours and heating up when the machine was turned off and back on it would be heavy starting, suddenly one day it would not start at all. I gave it to an local ET guy to have a look at it and it came out that the Injection Nozzles were bad. I replaced the Injection Nozzles (all 6 nozzles have the same serial number) , the previous nozzles that I removed had all different serial numbers. After replacing, the machine ran well for almost 3 days and started incurring the same problem again. so I contacted an ET guy from the local CAT dealer. Who came, checked and told me that the Control box and the transfer fuel pump were supposed to be changed. After changing these, the machines runs well, however the heavy start problem still exists after working for hours. The CAT ET guy told me that the Injection Nozzles should not be having the same serial number, this is causing the machine to heavy start. I already have incurred a lot of costs it would be really helpful if I got an idea on what exactly the problem is and what needs to be done.
usually the injector nozzles and the injector pump should sort out the starting issue and stalling under load or stalling when hot. Not sure about the control box being bad to be honest. Maybe he saw some error codes in there but kinda rare its that. Some things to check are: check bypass bleed diesel from injector nozzles (have procedure for that if needed) check the relief valve on the fuel rail maybe its stuck or not working properly the high pressure lines from the rail to the injectors need to be changed as they could be cracked etc (cat recommends changing them when injectors are changed) good idea to check the valve lash and clearance of tappets etc if your guy comes around with ET ask him to check if the pressure sensor is reading ok, the ECU will not turn on the fuel until the pressure hits a target value in the rail, so could be a faulty fuel rail pressure sensor that's misreading the pressure. Could also be a failed solenoid on the fuel pump but since you already replaced the pump you can eliminate that issue.