JD 310D 1400 RPM misfire

chuckn · Sep 11, 2017

Hi Folks, I'm a master tech with no tractor experience . I am working on a John Deere 310D Turbo diesel . At first it had fuel flow issues and after replacing the fuel filter, cleaning the vent cap and finally deleting the return valve at the Stanadyne injection pump she starts and runs without visible areation . Idle is around 1100 RPM indicated and is smooth as is 1500 RPM and up. The problem is a misfire right at 1400 RPM . It's very choppy and rough with a bit of rolling surge. There are 4400 hours on this tractor and it is well maintained but looks to have never had valves adjusted . Has anyone ever experienced this symptom ? I am work camping at a remote isolated Ranch in Montana and need to get this thing purring before the snow flies . I have only the owners manual and forums to go by and this is the best forum i've seen.

Dieseltech · Sep 11, 2017

If it helped with the return fitting removed that's the sign the injection pump needs repair. Fitting gets plugged with the broken retainer bits. Now the weight retainer is bouncing back and forth in plate slots. That's why it idles strange now. Best get it repaired BEFORE the pins shear off, locking the rotor, and breaking the shaft. Just returned a JD 4020 pump that came in with the same trouble.

chuckn · Sep 11, 2017

actually , the idle is smooth , as is 1500 RPM and up to it's governed limit . When i pulled the return valve i saw no foreign material in there , but i deleted it because it started and ran without stalling or surging , and the rectangular cartridge type fuel filter filled completely without air bubbles . It seems it had two separate problems all along . Maybe it is a governor ring fault with the injection pump , but that does not seem to follow the symptoms i have read . Thanks for your reply.

Anguspg · Sep 12, 2017

so, you get air intrusion with the return line installed? Do you get air constantly or just at certain rpm's?

chuckn · Sep 13, 2017

before i deleted the return ball and spring i had idle surge and intermittant stalling at working RPM

Anguspg · Sep 14, 2017

you might try another check ball assembly, the pressures might be building too high from a malfunction in return check ball.

chuckn · Sep 15, 2017

you may be right anguspg . I have already been told that if the check valve delete works it's because the injection pump has problems with the governor mechanism . I will advise my Rancher friend that a rebuilt pump may be needed before it gets worse.

chuckn · Oct 20, 2017

Thank you guys for excellent replies. After sending the pump out for reman , and getting it back in four days , the tractor runs great after install . Idle is a little over 800 indicated and it runs smooth all the way to it's 2500 governed speed .

Anguspg · Oct 20, 2017

(quoted from post at 08:18:32 10/20/17) Thank you guys for excellent replies. After sending the pump out for reman , and getting it back in four days , the tractor runs great after install . Idle is a little over 800 indicated and it runs smooth all the way to it's 2500 governed speed .

Would have been nice to learn of what exactly went wrong , as personally it's the learning that has always intrigued me.
Good to hear that the old gal is singing the proper tune again.

JD 310D 1400 RPM misfire

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