Fuel Knock Ram 3500 6.7 2017, bad PRV?
Thread Starter
|
Registered User
Joined: Oct 2020
Posts: 6
Likes: 0
Fuel Knock Ram 3500 6.7 2017, bad PRV?
Hello all,
Long story short - Had an issue with number 6 injector (knocking under load), I bought a used injector and replaced it.
Took the injector to a specialized injector dealer and it was tested to be bad during load. The noise begun after mistakenly fueling gas instead of diesel
The noise didn't completely disappear (Now I'm guessing it's the other injectors) So I decided to try and replace the fuel pump which I bought on the used market as well.
After replacing the pump - a noise from the pump's gear begun. Please watch the attached videos. 1
Decided to return the old pump which arrived with the car - but there was no change, still knocking sound from the gears.
So I had a theory that the gears were knocking because, during the knock the gear resists the movement and then go back with the right direction. To test that theory I decided to unscrew the main fuel line from the pump side to the rail - No change, went ahead and untighten the fuel line nut from the rail side - the noise instantly disappeared (as well as a significant amount of fuel) (-: Please watch the attached videos. 2
To eliminate one of the injectors I've performed an injector cutout test, which showed no difference in knock.
So now I'm suspecting the pressure relief valve (PRV) on the rail. unscrewed the banjo nut from both the pump side and the rail side - fuel is flowing !
Maybe the used pump came with dirt and caused a damage to the PRV.
Please help:
1. How can I eliminate the PRV as a source of the problem?
2. Is there any other component to be tested and how? fuel pressure sensor?
3. Watching the video - does the fuel pressure fluctuation seem right? (required rail pressure is 334, goes down to 317)
Video 1 - knocking sound and rail pressure
Video 2 - Fuel line nut untighten \ tighten
Thanks in advance !
Long story short - Had an issue with number 6 injector (knocking under load), I bought a used injector and replaced it.
Took the injector to a specialized injector dealer and it was tested to be bad during load. The noise begun after mistakenly fueling gas instead of diesel
The noise didn't completely disappear (Now I'm guessing it's the other injectors) So I decided to try and replace the fuel pump which I bought on the used market as well.
After replacing the pump - a noise from the pump's gear begun. Please watch the attached videos. 1
Decided to return the old pump which arrived with the car - but there was no change, still knocking sound from the gears.
So I had a theory that the gears were knocking because, during the knock the gear resists the movement and then go back with the right direction. To test that theory I decided to unscrew the main fuel line from the pump side to the rail - No change, went ahead and untighten the fuel line nut from the rail side - the noise instantly disappeared (as well as a significant amount of fuel) (-: Please watch the attached videos. 2
To eliminate one of the injectors I've performed an injector cutout test, which showed no difference in knock.
So now I'm suspecting the pressure relief valve (PRV) on the rail. unscrewed the banjo nut from both the pump side and the rail side - fuel is flowing !
Maybe the used pump came with dirt and caused a damage to the PRV.
Please help:
1. How can I eliminate the PRV as a source of the problem?
2. Is there any other component to be tested and how? fuel pressure sensor?
3. Watching the video - does the fuel pressure fluctuation seem right? (required rail pressure is 334, goes down to 317)
Video 1 - knocking sound and rail pressure
Video 2 - Fuel line nut untighten \ tighten
Thanks in advance !
Thread Starter
|
Registered User
Joined: Oct 2020
Posts: 6
Likes: 0
Was able to diagnose the problem:
when replacing an injection pump - make sure you do not rotate the injection pump gear.
The gear changes the timing - which will cause a gear slap.
another thing - there is a gear phasing. please follow the below procedure.
https://mopar1973man.com/cummins/art...ion-pump-r524/
when replacing an injection pump - make sure you do not rotate the injection pump gear.
The gear changes the timing - which will cause a gear slap.
another thing - there is a gear phasing. please follow the below procedure.
https://mopar1973man.com/cummins/art...ion-pump-r524/