Tractor ECU solinoid throttle control bypass?

Hi sorry this is not related to my Nissan but hopefully you are still happy to help.

We have a John Deere 6320 SE which is a fairly simple pre commonrail engine but the throttle control is electric and has been a intermittent problem for ~7000 Hours for numerous reasons Wiring\ECU and it is looking like we are back to replacing the ECU again.

Symptom is the engine flutters badly when trying to maintain a RPM above idle but it accelerates ok if you keep moving the throttle up at a steady rate till you stop moving the throttle or hit max then it starts to flutter.

Is there any way to replace the two wire solenoid with a manual throttle or at least bypass the ECU with a aftermarket controller for the solenoid?

Thanks



On a side note Recently my 94 TD42 was turning over a long time when starting especially when warm thankfully it was just the starter had a seized bearing and two of the 4 brushes were warn away making the cranking speed a bit low.
I didn't expect the dam thing to be harder to get out than our 2010 Hilux starter but there is not a lot of room around those bolts on the old td42 is there.

If the throttle control is electric, my bet is that there is probably variable timing controlled by that ecu as well. Perhaps check its not a sensor upsetting things? I had some weird symptoms and some flutter on the TD42 when the rpm sensor started playing up.

on vehicles after i think ,2007 we have a OBD11 port that we can plug a scanguage or similar device into to read codes . before 2007 they used a similar OBD port but used a device that used a different protocol . trucks and tractors may use different protocol again . if you can find out which port connector and protcol the tractor uses you may be able to buy a code reader device to scan your tractor and locate the problem . i think it would be a lot cheaper than just replacing parts and hopeing for the best

Thanks for the quick replies.

RPM displays seem to be reading correctly but without a wiring diagram I cant be sure if the displays are fed from the ECU or if the wires run from the sensor to the display then to the ECU.
There is a two wire plug beside the front crank pulley and the engine refuses to start if it is disconnected, RPM sensor?

Other than that the only wires I can see around the engine are (Ignoring back end)
Two water sensors.
One Engine Oil sensor.
Fuel bowl water sensor.
Fuel pump sensor which makes no difference connected or not.
Wire going in at air intake after intercooler.
Could be more.

Yes a computer can be plugged in to read errors but the John deer mechanics have tried using it and it never narrowed down the problem for them so they just proceed to replace every part starting with the cheapest and often least likely to be the problem. (Once they wanted to replace the engine fuel pump before the ECU and we said no thankfully as that time the ECU was the problem)
In the past turning the engine off and on usually fixed the problem (sometimes requiring multiple restarts) and more recently wiggling a bad wire at the fuel pump but that has since been fixed.
For the last few months restarting no longer helps so it may be more that just intermittent ECU problems this time.

I also checked the lift pump and tank pre filter this morning just to be sure it wasn't something simple but they are ok which was to be expected since it runs smooth while accelerating but it was something another mechanic suggested I rule out.

Any update mate.

Turned out to be bad contact in the ECU plug that time.

Now I am having trouble with the CCU supplying 8v instead of 12v to the PTO solenoid. No surprise JD wants another 4k+ to replace the CCU but since this is just a open-shut solenoid it just needs something to regulate the current so it doesn't burn out.
Any suggestions on what I could use to do this?