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.
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. HeavyEquipmentForums
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.
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?
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.
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.
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!
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.
Was this the fix? My 2017 331 is throwing the same code and iv changed filters
Yes the updated pickup tube with the strainer solved the issue. That part number above (AT516597) is the one I put in at the time.
Newb here. Has this proven to be a long term fix? I’m having the same dang problem w my 331G. Same codes. Same “Fuel Rail Pressure Low” message. Changed the filters. Cleared the hoses. Checking the tank and pick up tube tomorrow. Fingers crossed. I followed the link to the CAT thread recommended above. Nightmare. Expensive. And last I read, still not fully resolved. Thanks for any other info.
Yes, machine has had no problems since after the new pickup tube.
Thank you! I’m encouraged about my prospects now. Will check that out!!
Dont discount proper venting of the fuel tank, especially if it takes a while for symptoms to crop up.
Sorry to belabor my situation. Still having the same issue, same codes. (Last 6 of my VIN are 087988) Checked lines, pick up tube, vent tube, return, sending unit, and seal on gas cap. All ok. Fuel is clean and filters are also clean. Checked the sensor at the from of the rail. Looks good/intact but did not actually test it in any manner other than visually. Checked flow from lift pump (E-SHIN B6986 labeled on this pump. JD part MIU802381). It does not seem to be working well on the draw side. Almost zero flow when drawing from the tank. But very good flow when drawing from a bottle of deisel through an 8" section of fuel line. Also ran it with the first filter out of the circuit after reconfirming lines are clear (forced air and diesel through the line without issues) and no apparent kinks/crimps to decrease flow . Surmised that it just isn't "lifting" the fuel out of the tank bc the line is long. So my next step is to replace the lift pump. But JD wants >$400 for it, and my machine only has 200 hours on it. Is this a frequent issue with this pump? Does it fail with so few hours on it? Out of warranty so that's not an option. Just trying to find the pump at a lower price. Ive tried contacting the company that distributes this pump, but they're not returning my calls or email asking about the pricing of the pump. Thanks in advance for any help you can offer.
Is this the machine VIN or engine VIN? Post the entire machine VIN please.
336025U087988
That is not a Deere serial number. Post a picture of the machine's serial number plate. The plate will be on the frame tower on the right side of the machine behind the cab.
Thank you all for the assistance.
That fuel pump should put out 0.25 gal/min of flow. Fuel pressure should always be positive when the machine is running, no load and loaded. If the flow is that bad when connected to the fuel system, but OK when on a separate supply, then I would still suspect a suction side issue.
We will test the system before ordering a new pump by running a new fuel line from the tank to the pump. Cheap way to check since I cannot see the entire length of the stock fuel line. We blew air through it without trouble. But just checking to be sure/redundant. We will also vacuum test the stock fuel line. It seems to be tight, but it’s another cheap test before ordering that pump.
Has the water separator filter head been thoroughly checked for any debris or air leaks? Is the fuel shutoff valve on that filter head fully open? Loose and sucking air there?
Yes. There was no water. The filter is clean. We even took that entire filter housing out of the circuit to see if that was a source of excessive resistance to flow of diesel to the lift pump. It made no difference. The problem persists.