hi everyone

can i please ask for help as to why my fia master cut out switch does not cut the engine out ? it seems to kill the ignition power but the engine still runs on is this the alternator keeping it going ?


please help


striker-4age

Is it actually a FIA master switch ie. with resistor and extra connections at the bottom?

If yes, how have you wired it?

If no, then it is not a FIA master cut out switch but just a battery isolation switch in which case yes it is possible that the alternator keeps it running without battery.

I used a chunky relay in the wire from kill switch to alternator that open
ed/switched off, when the kill switch/ignition was operated. My kill switch was a non-FIA device.

[Edited on 18/6/12 by owelly]

will check the wiring and post up tomorrow

many thanks

striker-4age

hi again

ok looked at wiring to switch tonight

battery + across the large terminals

terminals 1 : 12v via ignition then via resistor then to ground.

terminals 2 : 12v feed to emerald ecu feed through.


so when i turn the key the ignition light comes on where it has lost the power but the engine keeps running is this down to a damaged resistor as it looks a bit brown ???


many thanks
striker-4age

Seen this thread http://www.locostbuilders.co.uk/viewthread.php?tid=108905 ?

hi mate

yes i have seen that

i must be going mad but do i need to take the supply for 1 from the master cut out switch battery termnial ? mine has a 12v supply but i cant see where it come from i think from the ingition switch....................should this still work ? just that my engine keeps on running ????




many thanks

striker-4age

Check the resistor it should be ~3 ohm, if you don't have a multimeter then simply wire it in series with a 5 watt bulb and a 12v supply, the bulb should light just not quite as bright as normal.

The big terminals are connected to the battery +ve and the permanent +ve feed for the car which will include the output from the alternator as it's also the charging path. It is this terminal which also feeds one of the terminal 1's, the other being the resistor to earth. With the master switch 'on' the 1 terminals are not connected, but when you turn the master switch it disconnects the alternator from the battery and joins the 1 terminals which allows the alternator output to dissipate away to earth through the resistor - if the alternator output is not grounded in this way it can keep powering the +12v circuits on the car, which can keep the engine running, which keeps turning the alternator...

As the diagram shows the 2 terminals are the power circuit to the coil, or the ECU in your case - connected when the switch is 'on', disconnected when 'off'.

So to answer your specific question, the 1 terminal is connected to the cut out switch big terminal but not the one that is directly connected to the battery +ve, the other one which is the +12v going off to the rest of the car. The other 1 terminal is one side of the resistor, with the other side of the resistor connected to earth.

Hope you get it sorted!

Shaun.

shaunb...................topman !!!!!!

i will be out in the man cave 2nite..................so hope i get it sorted, will let you know if i do



many thanks

striker-4age

eeeeeeeeerrrrrrrrrrrrrrrrrrr !!!!!!!!!!!!!!!!


the bloody thing still runs on ???

the wire to 1 was already taken from the battery lead to the starter, also changed the resistor as it was so brown ???


anyone ? i did buzz the switch through with my multimeter and it is making a contact for 1 when it is in the off postion ?

Can you buzz the big terminals and 2 connections on the kill switch to make sure they are acting as expected (connected when switch 'on', disconnected when 'killed'? Also measure the voltage on the supply to the ECU to check that it drops to 0v when you turn the kill switch off - try it with the engine off and then running. What happens if the ECU loses power, can the car still run in limp home mode? Are you using a Ford EDIS module, as I know these will continue to give a 10' advance even if no ECU connected? What is powering the coils?

Shaun.

Just noticed earlier that you said that the ignition light comes on when you 'kill' it. So how is that getting power? It works by being given an igntion switched +12v and the other side earths out through the alternator, but when the alternator starts generating it also outputs +12v and the light goes out. If you can get to the terminals of that light easily try to work out whether the alternator or the ignition supply is providing the 12v.

hi shaun

will get out there 2nite again, the ecu is an emerald m3d. it is just werid i did not fit the switch so i will have to check the ecu power cut out, and also check what ou said

will let you know if this fookin thing ever gets sorted

many thanks

striker-4age

Is it a diesel ?

no mate petrol 4age

Has this switch ever worked? I presume that it does stop with the ignition key? The '2' terminals effectively emulate the ignition key and remove power to the coils, the '1' terminals and big terminals just safely dump any alternator output and isolate the battery.

Shaun.

hi shaun

did not manage to have a look last night went out in it for a blast

yes was just thinking of changing the cut of on the terminals 2 from the ecu to a loop from the ignition switch this will work ok wont it ? what or how do i know what wire to loop throught the switch ?


shaun i see you are just up the road from me in ipswich what car you got m8 ?


thanks again

striker-4age

I don't see why that wouldn't work, the ECU is probably ignition fed anyway.

My car is the one in my avatar, 750MC Locost racer. 1300 xflow with coil and distributor, none of this fancy ECU stuff