John Deere 7310r running on 3 cylinders.

[Bob lincs]

Hi , anyone have any ideas ? Our 7310r is only firing on 3 cylinders it’s showing no error codes whatsoever. Injectors have been out and sent away and tested , all found to be in perfect working order . All the wiring has been checked and tested and no faults found . The injectors are wired in two banks of 3 and it’s 1-2-3 that are down 4-5-6 are firing fine . Anyone come across this before ??????

 

[Deerefarmer]

Have you had it plugged into service advisor?

 

[Timbo]

IT will be showing codes, and the smooth running correction will be pegged.

 

[Bob lincs]

Yes it’s been plugged in and had all the tests done but is showing no codes or faults .

 

[Timbo]

Make up 6 test leads, and swap the two inj plugs over. does it run on the other 3 cyl?

Under inj tests can you buzz all 6 injectors?

Is there continuity to all 6 inj from the ecu multi plug ?

Are you using a genuine S.A ?

 

[Bob lincs]

Make up 6 test leads, and swap the two inj plugs over. does it run on the other 3 cyl?

Under inj tests can you buzz all 6 injectors?

Is there continuity to all 6 inj from the ecu multi plug ?

Are you using a genuine S.A ?

All the tests have been performed by a JD dealer and still drawing a blank

 

[milkloss]

I would say it’s likely to be the Ecu giving grief. If the injectors are fine and wiring checked what else could it be?

 

[kiwi pom]

All the tests have been performed by a JD dealer and still drawing a blank

Surely Deere have some kind of tech support dept that springs into action when the dealer cant solve a problem?
Or is the dealer unwilling to admit to HQ that they cant diagnose it?

 

[Timbo]

Your dealer isn't upto much then. I'd suggest an ecu fault too at this point ( output drivers) also, but id want to prove it via diagnostic.

Scope the inj wires with a current clamp and see what the ecu is sending out, or scope the ecu power feed and look for 6 capacitor charges- if you added the crank sensor signal you can see the firing order- whats missing.

If they scope the injectors you should see the pintle open and close in the trace. Could be opening but blocked, could be being powered but not opening. You'll see opening voltages too - would confirm or condemn the ecu