Fuel Cut Off Solenoid

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31 Oct 2012 20:12 #1 by dandjcr
dandjcr created the topic: Fuel Cut Off Solenoid
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Dandj
Member
Posts: 367
In my never ending quest for single points of failure, the fuel cut off solenoid on the injector pump is a critical item.
If it fails the engine can't start or run, so I researched it a bit and wrote up some notes on what to do here, as part of the minimum electrical requirements to start and keep the engine running.
Solenoid failure is an uncommon fault (unlike the wiring to it) and modifying it to allow the engine to start might be tricky, but it can happen so it's worth putting on your "Things To Do If Desperate" list.
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David and Janet Ribbans, Oka 148

August 14, 2011 at 9:29 AM Flag Quote & Reply

James & Usha (THEByleDuct)
Administrator
Posts: 161
Again great write up David. Thanks for sharing your incredible wealth of knowledge and good common sense.
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OKA #072

August 14, 2011 at 1:10 PM Flag Quote & Reply

Rick Whitworth
Member
Posts: 74
Question on the fuel cut off solenoid and a warning for those using standard XT air step...

The label on one of the fuses in the XT fuse panel shows that the fuse for the bus step solenoid and relay somehow shares something to do with fuel supply.
The fuse is shown as F7 on the Vehicle Circuit Diag of my XT Service Manual Sect 10 p145 and the bus step solenoid and relay are shown as R2,R3.

There is no reference to the fuel cut off solenoid anywhere in my circuit diags but if you pull this fuse out it definitely prevents the engine from starting.
Upshot is, if the bus step circuit blows the fuse then you can't start the engine!
Can anyone confirm that the "fuel" label on F7 in the fuse panel is refering the circuit for the fuel cut off solenoid? (or something else that might stop fuel supply ...maybe the left right tank switch)
February 9, 2012 at 9:57 AM Flag Quote & Reply

Dandj
Member
Posts: 367
Rick, I agree there seems to be no mention of the fuel cut off solenoid on my circuit either. Maybe it's because the injector pump is an engine component and not on the body but that's not an excuse, it ought to be referenced somewhere.
On my XT the Fuel Cut off Solenoid is marked against F11 on the fuse panel (see pic) along with Fuel Changeover Solenoid and Hour Meter but on the circuit these are shown coming from F5 so something is screwy. My F7 is for Instrument Lights.
Unfortunately I drive my fuel cut off solenoid from a separate electronic circuit (to prevent accidental starting) so I can't test which fuse it was originally connected to, but logically it should be grouped with other "ignition" circuits such as alternator warning light, oil pressure warning light, tacho and speedo (F5 on the circuit, F13 on my fuse panel, which is where they actually are).
I would suggest you rewire your cut off solenoid to the "ignition" fuse (whichever that is on your Oka) to avoid the situation you mentioned.
I suspect the circuit is probably representative of the actual wiring but the fuse numbering was changed at some time, and maybe some of the functions were moved as well. Sorry this doesn't answer your question, except to confirm something is weird. Does anyone have a circuit which reflects my fuse panel markings?
No doubt the LT is different again.


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David and Janet Ribbans, Oka 148

February 10, 2012 at 3:34 PM Flag Quote & Reply

Rick Whitworth
Member
Posts: 74
thanks David,
yes my XT fuse panel is exactly the same as yours and it is fuse 11 in the panel that is the culprit. If the bus step circuit shorts and blows this fuse (or if you remove it) the engine immediately just spins over without firing. When the fuse is replaced the engine starts fine.
This may be a succession of events because I currently have the left fuel tank out to work on the step. It may be that even though the fuel chanageover is switched to the right tank, with a blown fuse the fuel supply reverts to feeding from the left tank (which is not there). However I doubt this because the bowl under the fuel filter is still full.
There are a number of labels on fuse 11..
FUEL
STP SOL

FUEL
C/OVER
SOL.

HOUR/M
SPD. LIMIT

..Wonder what the first ref to FUEL is.
Will be away in the high country this weekend but will do a bit more sleuthing next week to see what fuse F11 controls.
You are right my XT manual shows the step solenoid fuse as F7 whereas it is F11 in the fuse panel, F7 on the panel is INSTR LIGHTS
Rick
February 10, 2012 at 6:47 PM Flag Quote & Reply

Dandj
Member
Posts: 367
Rick, I assume that they mean Fuel Stop Solenoid (the Cut-off solenoid) , Fuel Changeover Solenoid (changes tanks), Hour Meter and Speed Limiter (where fitted).
Yes, the tank change over solenoid has no memory, so it will revert to a default tank if the power is removed/fuse blown. I didn't know which one, but it seems to be the left (passengers side) tank. It will take quite a time for the fuel bowl to empty since there will still be a litre of fuel in the main filter unit to use up first.
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David and Janet Ribbans, Oka 148

February 10, 2012 at 7:11 PM Flag Quote & Reply

Rick Whitworth
Member
Posts: 74
My assertion above that the bus step solenoid is on the same fuse as the Fuel Stop Solenoid was wrong.
The fuse was blown by shorting the Fuel Changover Solenoid when the left tank was removed. All circuits now back up and running OK including lengthening of wiring looms and AC compressor hoses to evaporator in the cab roof. (All done for modiications to floor area above the bus step to accomodate shower base in doorway and portapotti locker behind/under passenger seat).
While doing this I started comparing the fuse panel with the XT Manual. I have posted an image in the photo album www.oka4wd.com/apps/photos/photo?photoid=149222019
along with circuits from the manual as I don't have a permission to put em here.
It appears that the manual refers to an earlier version of the XT and that by XT147,149 fuses F1 to F8 were moved to nos 9 to 16 of the bottom bank of the fuse panel and F9 to F12 became nos 1 to 4 on the left top bank. Some elements connected to F6 have been fused separately to nos 5 to 8. The horn seems to have been shifted from F7 to F6.
Circuits also show the ignition key switch links to some relays not refernced on the fuse panel and as David points out, there is no ref to Fuel elements in the circuit diagrams.
So if anyone has updated circuits for the later model XTs it would be a great help.
February 14, 2012 at 2:50 AM Flag Quote & Reply

Dandj
Member
Posts: 367
Good sleuthing Rick, useful conversion table.
I'll insert it in my manual ready for our next electrical escapade.
Incidentally, when the fuse blew and your fuel changeover solenoid reverted to the left tank, did the fuel gauge also change with it, or were you left with fuel from the left tank and the gauge reading from the right tank? I don't see that on the circuit either.
It would be very misleading if the fuse blew or the wire broke while travelling since you might not notice it.
On our treks I flick the changeover switch quite often to check how much fuel we have in each tank, for peace of mind, but that still does not confim which tank the solenoid is actually set to. I fear another warning light is called for.

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David and Janet Ribbans, Oka 148

February 14, 2012 at 7:27 AM

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