331G Low Fuel Pressure

[PeteG]

Hi,

We have a Deere 331G serial number 304482. It’s been putting up code 157.18, Fuel Rail Pressure Moderately Low. I tried filter changes, as well as a bit of diesel additive and biocide as I was following another thread on here with similar issues, but no luck so far. When in service mode it shows:
1 361.0
3 361.2
And through diagnostics I can see the fuel pressure sensor at 2600 reading 100-130 MPa with up to 3V. When the machine throws the code, fuel pressure jumps down to 70+/- with 2v. The other odd thing is it is as if the machine idles down, it doesn’t stutter at all. It’s been doing this for a few weeks now, slowly getting more prevalent. Today ran it for an hour and it popped up towards the end. I’ve been clearing the codes after I make small changes to see if it had an effect, but so far it keeps popping the same code and derating.
Dealer is a ways out for field service schedule so would like to get a head start if I can. There suggestion was to check the fuel pressure sensor wires and reconnect to sensor, which worked for one day but the code popped up again. Thank you for any suggestions.

 

[Nige]

Not a Deere but a Cat machine and a similar problem. Different terminology (Fuel Rail Pressure vs Fuel Rail leakage) but I would suspect the problem is similar.
Go to Page 3 of the thread and see what the issue was caused by...........it might give you a few ideas of where to look next.
https://www.heavyequipmentforums.com/threads/cat-299d-engine-fuel-leakage-1-error-code-1239-1.87072/

 

[BigWrench55]

Cheap and easy way is to replace the fuel rail pressure sensor and relief valve. Without service advisor it will be difficult to diagnose. You can have a failed fuel suction control valve, poor fuel delivery on the low pressure side, or one or more injectors failing returning to much fuel. You will need to find a way to isolate all of the return lines and measure what is returning back to tank to determine if you have a bad relief valve or injectors. Special block off fittings to determine which injector is failing.
A word of caution... Take extreme care when opening injector lines. Its best to wait a few minutes before doing so. These fuel systems can make as much as 30,000 psi.

 

[PeteG]

Thank you both. Will definitely try to flush the filters and lines a few times to ensure the fuel is clean, as well as try a new pressure sensor and relief valve first. I’m assuming there is no way through the onboard service menu to help diagnose this?

 

[mg2361]

First thing I am going to suggest you do is drain your fuel tank. Remove your fuel level sending unit. Then look into the tank at your fuel pickup (a common issue with the "G" SSL). It should be straight down into the lowest part of the tank about an inch or so off the bottom. If the bottom of the pickup is curled it can suck against the side of the tank creating your fuel pressure issue and setting the code. I would suggest you order and install the new style pickup anyway (part # AT516597) . It has a strainer on the end that will prevent that from happening. Then run it to see if your issue goes away.

 

[PeteG]

Thank you for the suggestion. Hopefully tomorrow I will get a chance to bring the machine back to the shop and take a look. While doing that, I’ll try to make sure I blow the lines back as well as drain the tank to eliminate any possible dirt/material from within the system. The sensors are definitely a little expensive to replace without diagnosing them for sure.

 

[PeteG]

Just an update. Drained tank and blew air through the lines. Fuel seemed very clean, and next to no sediment, which was very surprising. I did pop off the pickup tubes and they were slightly curved to the side of the tank, so I clipped them up about 1/2 inch as a test while I wait for the correct pickup tube to come in. Ran it for about 2 hours and didn’t have an issue so hopefully we got it! One question I do have though is why are there 2 pickup tubes in the tank? I even double checked on Deere’s parts website and two fittings are labeled pickups, with an additional fitting marked as the return. Thank you for the help everyone!

 

[mg2361]

One question I do have though is why are there 2 pickup tubes in the tank?

There should be a total of 4 hoses coming off the fuel tank on the right side. The rearward most hose should be the return hose from the fuel cooler. The hose just in front of that should be the vent hose which connects to a steel tube attached at the fuel filler neck. The next hose moving forward will be the pickup which goes to the water separator filter. The last hose moving forward which you may not see unless the cab was up is the hose which goes to the breather.