Hey everyone got a 721G wheel loader that runs good at idle , has very clean fuel , checked lines going from tank to filter housing to the bosch CP3 pump no signs of leaks when you rev it past 1600 rpms it throws code 17509 for High pressure fuel has exceeded desired limits. So far I have changed fuel filters , changed fuel rail pressure sensor on common rail , preform test for cp3 pump at idle got less than 1000 ml of fuel , no fuel coming from pressure relief valve at idle both tested for 1 minute. I robbed a fuel metering unit off another machine on the yard for the CP3 pump didnt change too much other than a 100 rpm increase for a few seconds putting it at 2200 instead of 2100. Injectors work well during cutout test, also no leaks coming from the fuel tank. This machine runs well not rough , stalling, runs good at idle , and when revved up but once it reaches 1500+ rpms it cuts back rpms and codes code can be cleared. If anyone has seen this issue before , or any tips relating to further troubleshooting it would be appreciated.
Was there any contamination on the end of the fuel rail pressure sensor on the common rail? I just went through this on a 621. My sensor was covered in a black mcgoo. Maybe pull your new sensor and double check it.
I preformed an Injector return/leakage test on the loader yesterday preformed the test supposed to be getting 100 ML of diesel fuel at idle for 1 minute. I tested it twice got around 375 ml first time got around 400+ the second time. Tech support said replace all 6 injectors and crossfeed tubes. In the process of putting it back together to test Monday got all new injectors in today.
How did you get on with changing the injectors ?
It worked out great cranked it up for the first time after getting halfway put back together sounded like a brand new motor! It's nice those iveco/Fpt 6.7s you don't have to do injector files , or trim codes just pull em , install new ones with new quill tubes.
Yeah think I might have the same issue here, what hours are on that engine ?
Around 2350 hrs
Run a clear line to a bottle or container from the fuel injector return line fitting on the back side of the motor if you got more than 100 in a minute new injectors , and quill tubes , but check your fuel relief valve , metering unit screen , lines all that