John deere 450D lc low fuel rail pressure

[Brad93]

I have a john deere 450D with 13200 hours. Iv been fighting issues with 1239-1 code. I have changed filters / overflow valves checked all screens all lines presure at injection pump at idle is around 37 or so hard to tell because it jumps around so much ! And I don't know if that's normal ? It seems to jump 15 or even 20 psi the needle is almost blurry.? But it seams to be hit and miss on how long it runs well befor it throws 1239-1 code and iv noticed the pump control valve the second one when the fault is present I can unplug the conector with no engine tone change if I Leve the second one plugged in and unplug the fist it will slow the engine down to a pretty low idel about 450 rpm. Plug the #1 back in jumps right back to 750 rmp. I started testing wires back but I don't know how much resistance the ground wire to pcv sould have. ? I pretty consistently get 33.9k ohms to a frame ground on both ground wires 68 k ohms across the 2. Iv switched pcv to see if the issue followed the pcv and it didn't it stayed at the second one. I'm being to bash my head against this thing. With all the work iv done so far the excavator runs way better than when I received it ! It would consistently blow white smoke and sputter no power but after cleaning all lines and screens and new overflow valves all 3 it runs alot better I can get fuel consumption rate of 70 +gallons an hour on the monitor for a little while before it starts loosing power and faults out. I checked the fuel presure limiter. but I believe the system was already running on one pcv and possibly couldn't open it ?. Iv tried a few other things but If anyone relate and have some advice il much appreciate it ! And if any questions feel free to ask

 

[mg2361]

Welcome to HEF brad!

Rail relief been checked for leakage? Injector leakage? Overflow valve on the injection pump?

 

[Brad93]

Thanks iv read through qnot of the threads and alot of information i have used i look forward to using this great resource!

i replaced overflow valve on injection pump and the 2 on final filter housing. I have not actually measured the injector leakage but I did pull the leak line off the head and cap it and the amount of fuel coming out of the head was very little. As for the rail pressure limiter I did have the Iine off and caped and with is boging down while running there was no fuel comming out of the pressure limiter but I believe at that time ecm had allready had the one pcv turned off, possibly the presure can't get high enough? I think im gunna have brooks tractor come and plug into it and see what else is happening when the code pops up. Possibly pressure is to high ?

 

[BigWrench55]

With hpcr fuel systems you will need to isolate all of the return fuel lines and measure how much fuel is being returned from the injectors and the common rail. Also if you have poor flow to the high pressure pump, or if air is being introduced to the system. That can also give you a low rail pressure code. Make sure that you have good fuel flow to the pump and check for any loose fittings from your filters to the pump. If you can isolate the return fuel and measure what the injectors and common rail are returning. Then post the results here. Service advisor will be needed for further diagnosis. And for the love of God. Be careful when opening any connections on the high pressure side. Wait at least 5 minutes after stopping the engine before doing so. You don't want to get hydraulic injection from fuel. That will ruin your day quick and will require surgery.

 

[christopher smith]

We had this issue with our 450. Checked everything new filters. Nothing seemed to fix it. I showed up on the job after 2 weeks still not fixed. Decided to blow air in the fuel line back to the tank. That where I found our problem. There was a fuel shutoff valve in the line. Opened it up. No problems since.