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fuel cut out switch

Posted: Sun Dec 10, 2017 5:12 pm
by straggler
I seem to have a dodgy fuel cut out switch on my 96 406 XUDT (the one under the bonnet on the nearside). It seems to trip into the off position when I'm trying to start the car and takes loads of tries pushing it in and out until it clicks back into the on position (when I hear the fuel pump switch back on). Once the car is running it's fine.

This is the second time I've had issues with a fuel cut off so I'm wondering if I can just bypass it? If I disconnect it and then just join the two wires together will that work?

Cheers!

Re: fuel cut out switch

Posted: Sun Dec 10, 2017 7:56 pm
by steve_earwig
I've no experience of them but I suspect you'll be fine. They don't seem to do anything other than kill the power to the ecu & fuel pump in the event of a shock (crash, bump in the road, sneeze). A lot of 406s didn't even get one, my 2.1td didn't.

Not finding a 406 XUD9 wiring diagram but there's an 11 here http://www.autoelectric.ru/auto/peugeot/406/p8c/p8c.htm the 1.9 is probably similar, you're looking for 1203 which is right next to the double relay above the ecu. There is an XUD9 diagram for an 806 on there but it shows 3 wires - the third seems to head off to the central locking unit :?

Re: fuel cut out switch

Posted: Mon Dec 11, 2017 7:48 am
by straggler
It's a weird one. If the car is used regularly there's not a problem but if it's left for a few days it will trip and then be a sod to reset. Don't really want to be hacking at wiring until I'm sure it can be bypassed without a problem.

Would you happen to know what's inside the switch? I'm thinking of giving it a WD40ing to see if that helps.

Re: fuel cut out switch

Posted: Mon Dec 11, 2017 1:38 pm
by Doggy
Didn't think XUD's had lift pumps, or am I missing something?

Re: fuel cut out switch

Posted: Mon Dec 11, 2017 2:19 pm
by straggler
It cuts off the fuel to the injector pump.

Re: fuel cut out switch

Posted: Mon Dec 11, 2017 10:53 pm
by steve_earwig
1208 diesel injection pump (advance corrector, fuel cut-off solenoid).

I guess it's like Siemens injection, no lift pump so they have a primer bulb to get the fuel to the injunction pump. Or gravity perhaps...

I've no idea what's inside the cut out switch, I'm guessing it's a weight on the contacts, so if there's a sudden sideways force the weight gets dislodged and the contact broken. Or maybe it's JFM :shock: anyway a lot of 406s didn't have them so I don't think they're essential.

Re: fuel cut out switch

Posted: Mon Dec 11, 2017 11:21 pm
by GingerMagic
I just Googled it, and surprise surprise Google sent me to a page full of broken down Fords in 'Murica... :lol:

Its seems quite a common thing to do - just joining the wires together will bypass the switch and fool the engine into starting, as long as you join the correct wires of course... :roll:

Good luck in sorting it.