Ignition Troubles S3

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Deetd4

Deetd4

New Member
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164
Location
Co. Down Northern Ireland
Hi all, still working through the maze of problems on my S3. On the bulkhead of my S3 I have a ballist resister. This has been wired directly to the battery bypassing the key. I have been looking around the engine bay for a live feed from the key. Does anyone know what colour the wire is I'm looking for. If I have read it right the Haynes manual says white. Also, the coil is ballist resisted so do I also need the one beside the coil and if so should it not be mounted in the front of the vehicle behind the grill so as the air flow will be keeping it cool. After the engine is running for a while it gets so hot you couldn't touch it.......



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The feed to the coil should be white and usually comes from a junction behind the dash or the fusebox BUT... it is a landy and someone might have replaced it or done it different. The power feed MUST be ignition controlled. If you have a constant power source it will cook the coil. On the coil side the power feed goes tone side of the ballast resistor. The other side goes to the positive terminal on the coil. The negative terminal goes to the distributor. There should only be one ballast resistor and it should be close to the coil. In normal operations it shouldn't need cooling. I've had the coil om the bulkhead ot on top the rocker cover. It makes no dofference. If the coil has been getting very hot it may be bug****d. If you have a multimeter you can check the coil, by checking its resistance. Between the terminals it should read around 1 to 1.5 ohms. If it reads 3+ then it doesn't need the ballast resistor. Measure between any terminal and the centre HT terminal it should read 5-7.5 ohms. Hope this helps. Mike
 
The coil is probably not original.
Ballast resitored coils tend to be 6 or 9 volts, the idea is that a relay is connected to bypass the ballast resistor whilst the engine is crakning, as whilst the starter is operating the battery voltage drops making the spark weaker, a 6 volt coil would still produce a good spark, then switching in the resistor when the engine has started maintains your 6 volts.
A permanent supply is bad, and needs to be sorted, you could run a wire to the starter solenoid to bypass the ballast whilst cranking, but if your not that confident I'd advise against it.
 
Dee, seriously suggest looking at your wiring that you buy a ratchet crimp tool and some crimps, you'll wish you had when your on a country lane somewhere and she'll not go.
 
Thanks for all the replys. There is a lot of very helpful information contained in there. After reading the haynes manual I discovered it was a white wire running off No.8 fuse that went to the coil. Trouble is that when I open the fuse box up nearly all the wires in there were black. I then ran a wire from No.8 fuse to the coil, hey presto! a switched live feed that stopped the truck when the key was switched off. Problem is now that while the engine is cranking there is no live feed at the fuse. I have checked all the contacts from the back of the ignition to the fuse box and cant find a feed thats is switched live and stays live while the engine is cranking. So what I am proposing to do is take a second live feed from the switched side of the selenoid. This will then give a live feed while cranking and the fused live feed will take over when the key is released. So what do you think? Is this a fesible idea? Or would there be another way in which I would only need 1 live feed.
 
It's not a diesel been converted to petrol is it? It sound like a diesel ignition switch.
 
I fyou take a feed from the main feed on the solinoid when the car is running the feed to the coil will try to turn the starter, on the solinoid should be a small conector this should run to the coil
 
Not as far as I know Dave. Although at some point it had a gas conversion done. All the hardware bar the tank was there when I bought it. It's not the origional engine in it. I know this cos all the MOD vehicles have an odd green colour on the engine and ancillaries. Far as I can see it's always been petrol I think its just had a lot of really bad short cut preformed on it. Now I have the job of trying to get it all back as close as I can to what should be there. It is possible that the ignition switch is from a Diesel, not sure if it's a different configuration or not but I wouldn't rule it out.
 
Thanks nongrokal, will i find this on top of the solinoid between the two cables that got to the battery and to the starter, there is a small button type of thing although it's hard plastic.
 
Use a meter or a check lamp, disconnect the thin wie going to the starter solenoid so it wont start than check the terminals going to the ignition switch, if none of them are live with ignition and still live while in the crank position then its a diesel ignition switch, you'll have to replace it with a petty one.
Kinda sounds like this doesnt it, you could 'bodge' it for the time being and connect up a toggle switch to the ignition coil.
 
sorry i had asumed you had a pre-engage starter, as you have not there are two diferant solinoids the one you want has two spade terminals plus the starter and batery leads, if you only have one spade terminal you can not use a risister type coil. in this case find a feed off the ignition switch that stays live when cranking, if you do not have one then you have a deisel switch
 
You could if you were electronically minded connect a suiatble diode (an alty rectifier would do it) between the starter motor thick cable (with a fuse inline) and the coil side of the resistor, this would give a direct feed to the coil bypassing the resistor whilst the engine is cranking (which is what a ballasted coil is designed for), but blocking current flow from the ignition supply back to the starter, would be cheaper and easier than another switch, just a little involved.

Edit: one thing I just thought of, dunno if the heater plug terminal on the diesel ignition switch is live in the crank position or not (would have thought it was, test it with the test lamp), but seeing as this isnt used for the petrol you could connect this to the coil side of the ballast resistor, this way even though the ignition supply is removed in the crank position the coil would still get its feed from the heater plug terminal on the switch whilst the engine is cranking, also the ballast resistor would be bypassed whilst cranking giving a better spark and using the coil as designed.
 
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