JCB JZ140 Idle/throttle issue

[Bedford139]

Hi all,

Hopefully someone on here might be able to point me in the right direction.
Recently purchased this JCB and it currently has an issue that I’m looking to resolve.

When you turn the key the engine turns over but doesn’t start. If I wedge the cables open on the fuel pump and then try and start it it fires straight up. It has an Error code 108 which I believe is the flywheel sensor?

Is there any way to view the full list of error codes?

The JCB is a 2007 model. Any help is very much appreciated!

 

[JVM]

Hello Bedford 139.

Have you received a reply to your post?

I have a similar problem in the same machine in that the display shows the error code "108 flywheel". The difference is that recently, on shutdown (the key does not usually stop the engine, I have to press "Emergency stop") the engine would run on, barely turning over, almost like an antique "hit and miss" engine.

Now, it is happening at start-up. I'm wondering if the error code is simply reporting that the engine is not running at a minimum speed and that the flywheel sensor is not part of the problem which lies elsewhere. Since it is (was) an intermittent problem, I'm assuming it is an analogue problem, e.g. a bad connection) not a digital problem e.g. with the computer - although having said that, the engine speed control appears to not be working. I'm about to try your solution of wedging the pump cables.

JV

 

[JVM]

Problem solved - I think!

First, disconnected the flywheel sensor - starter wouldn't operate, so I established that the computer needs a signal.
Tried wedging the throttle open a bit - cannot move it.

Then disconnected the sheath of the stop cable, and the stop lever on the pump moved a good 25mm forward. Engine started, throttle control works.

So... I had already adjusted the solenoid end-stop bolt to the maximum, supposedly allowing more movement of the cable, and there is no adjustment left on the sheath end clamp, so maybe the cable is not running freely in its sheath. I'll try to get the cable assembly vertical & drip some Ballistol down for lubrication.

 

[JVM]

Problem solved - I think!

First, disconnected the flywheel sensor - starter wouldn't operate, so I established that the computer needs a signal.
Tried wedging the throttle open a bit - cannot move it.

Then disconnected the sheath of the stop cable, and the stop lever on the pump moved a good 25mm forward. Engine started, throttle control works.

So... I had already adjusted the solenoid end-stop bolt to the maximum, supposedly allowing more movement of the cable, and there is no adjustment left on the sheath end clamp, so maybe the cable is not running freely in its sheath. I'll try to get the cable assembly vertical & drip some Ballistol down for lubrication.

It is clear the flywheel sensor is not the problem; it simply reported
that the flywheel was running slow, so the computer disabled the throttle.

The problem is that the solenoid is not pulling the engine-stop lever far
enough. Two possible reasons: one or both adjustments have moved, or the
cable has stretched e.g. by fraying as a result of binding in its sheath.
Ballistol applied several times today has the cable moving freely again.

There are two adjustment places, one each side of the solenoid. The outer
one, at the "back end" of the solenoid, appears to be to limit the travel
of the solenoid shaft when it is energised. Tother is on the engine side
and appears to determine how far the stop lever is moved.

I've backed the first almost right off, but even so the engine still does
not quite stop.

The other is a problem, coz although there is maybe 12mm of thread
available, I cannot undo the locknut on the adjuster coz of it's location
and partly coz I don't have two open enders which fit tightly.

Normally in that situation I'd look to removing the complete assembly, but
the idiot in there before me has damaged the slots on the Phillips head
M8 screws. And did I mention the need for key-hole surgery skills?

The idea of a rope from the stop lever into the cabin is looking good at the moment!

JV