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JohnT

XD distributor wiring

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Hey guys, 1st post... I've got an XB coupe and just purchased another engine for it which uses an XD electronic dizzy. Before the engine was pulled out the guy took me for a drive in his car and so i know its a runner etc, thing thats baffled me a bit is the wiring. In the attached picture , bit hard to see, but the pink is going to the positive terminal on the coil and the green is going to the negative. Note too there is a spade connector on the negative side only, and this is what he was running ignition power to. I `think' he's basically got the coil wired backward... shouldnt it be green and the spade terminal on the POSITIVE, and the pink on the NEGATIVE? I mean, the way he's got it was obviously running but am I right saying the coils wired the wrong way around? Cheers in advance for any help you can offer....

xd dizzy.JPG

XD2.JPG

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The extra terminal on the negative would be tacho signal. The positive should have a feed from ignition and tee off to feed the coil module, or vice-versa, as long as both the coil and the module get 12v.

I will stress that you need a 12 volt coil and an actual supply of 12V at the coil, not the usual 9V via a resistance wire that would have been there with the points. I came across this exact issue on a mate's XB coupe after replacing plugs, leads, coil and module, and still getting a weak as piss spark. Jumped it straight from the battery, and vroom!

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10 minutes ago, gerg said:

The extra terminal on the negative would be tacho signal. The positive should have a feed from ignition and tee off to feed the coil module, or vice-versa, as long as both the coil and the module get 12v.

I will stress that you need a 12 volt coil and an actual supply of 12V at the coil, not the usual 9V via a resistance wire that would have been there with the points. I came across this exact issue on a mate's XB coupe after replacing plugs, leads, coil and module, and still getting a weak as piss spark. Jumped it straight from the battery, and vroom!

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Cheers, thanks for that.. my point is that he only had the one spade terminal so looks like he was running ignition thru the negative side...would you agree that by the looks he's got the coil connected back to front? And yes, 100% agree with you on running 12V, not resistance wire.

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Cheers, thanks for that.. my point is that he only had the one spade terminal so looks like he was running ignition thru the negative side...would you agree that by the looks he's got the coil connected back to front? And yes, 100% agree with you on running 12V, not resistance wire.
Yeah coil wires looked backwards, yet for some reason it still worked by back feeding IGN+ into the negative (switched side) of the module? Sounds wacky to me.

A coil will fire backwards, this is how some wasted spark coil packs work (Holden/Buick V6 comes to mind) in that one coil fires two plugs (kind of) in series; one plug fires the usual way but its mate gets the spark backwards (ie one gets a negative zap and the other positive)... So yes your plugs will fire but they will wear out the earth strap quickly.

Still doesn't explain how yours managed to work... Got me stuffed

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3 minutes ago, gerg said:

Yeah coil wires looked backwards, yet for some reason it still worked by back feeding IGN+ into the negative (switched side) of the module? Sounds wacky to me.

A coil will fire backwards, this is how some wasted spark coil packs work (Holden/Buick V6 comes to mind) in that one coil fires two plugs (kind of) in series; one plug fires the usual way but its mate gets the spark backwards (ie one gets a negative zap and the other positive)... So yes your plugs will fire but they will wear out the earth strap quickly.

Still doesn't explain how yours managed to work... Got me stuffed

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so by the looks ( at least as far as I understand it) the only thing he had wrong was the coil itself.. so, yes, the power is feeding into the `wrong' side of the coil but then goes on to the green wire to the module, and pink goes back to ( what should be ) the negative side if that makes sense? So, coil will still work even though its `wrong' but module is wired correctly?  Or, in other words, just looking at the module by itself, it should be power on green, negative on pink? 

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1 minute ago, bear351c said:

Pink wire comes from ignition circuit. 

oh really? and then green goes to negative? So, would the module work if it was wired backward? just trying to figure how in hell this was running as hes got it set up? ( and it was running well, too, when we went for a ride in his car before the engine was pulled)

 

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oh really? and then green goes to negative? So, would the module work if it was wired backward? just trying to figure how in hell this was running as hes got it set up? ( and it was running well, too, when we went for a ride in his car before the engine was pulled)
 
Sounds like that setup is arse-about. Pink is IGN like bear says, green is the switched negative side, and tacho feeds off that (should be white/green)

938b3600aca240ee15a66e9eed27bffd.jpg

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1 minute ago, bear351c said:

I have no idea...!  Sounds like the coil was 'backwards', and the module correct. 

so.. pink off the module is ignition source (positive) and green is negative then?

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1 minute ago, gerg said:

Sounds like that setup is arse-about. Pink is IGN like bear says, green is the switched negative side, and tacho feeds off that (should be white/green)

938b3600aca240ee15a66e9eed27bffd.jpg

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Cheers, thank you...looking at it, maybe I'm basing too much of my assumptions on that one spade terminal's location! So if I just run positive from ign to + on the coil I should be good... thank you so much guys, huge help!!

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10 minutes ago, bear351c said:

Cool.

 

Got any pics of the Hardtop..?

 We love photos. 😋

yeah sure! The black shot is a few months ago...looked OK in photo's but it had lots of little flaws etc - paint was about 6 years old and was cheapie anti rust paint from Bunnings, so looking at around $20 worth of paint there I sprayed myself. The right hand shot is how it currently looks, getting those flaws out before I spray it again...its definitely not a high dollar car, in the last 18 years, including buying it, buying the donor ZH the ( current) 351 came out of etc., there is about 4 grand in the whole car. but I love it, keeps me going. The new engine is a 302 C with head work, a cam, roller rockers, gear drive, Edelbrock Performer, 660 Quickfuel and a bunch of other stuff. The car it came out of was an XRGT and only came out to make way for a 393 stroker he's got for it, 18+K he's spent on that engine.. I went for a ride in it and was hooked! Very powerful, should be great fun!

rear view.jpg

primer.jpg

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Uncanny... My mates one (with similar ignition issues, same dizzy) has also been done in a cheap matt black. He bought it from Mildura a few months back, epic road trip for both of us (from Sydney). Also has a 302, possibly has a bit of work done, 600 Holley vac, C4 and 9 inch. So far, no rust to be found except a few spots here and there.a0a032725f17698231c29370a8e23275.jpga1c463a8f70c493e3d154291367c6289.jpg

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1 minute ago, gerg said:

Uncanny... My mates one (with similar ignition issues, same dizzy) has also been done in a cheap matt black. He bought it from Mildura a few months back, epic road trip for both of us (from Sydney). Also has a 302, possibly has a bit of work done, 600 Holley vac, C4 and 9 inch. So far, no rust to be found except a few spots here and there.a0a032725f17698231c29370a8e23275.jpga1c463a8f70c493e3d154291367c6289.jpg

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wow that IS weird... even down to the grey primer painted taillight panel it had as part of the sanding down process ! I previously had gold centred Globes on it too ...

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wow that IS weird... even down to the grey primer painted taillight panel it had as part of the sanding down process ! I previously had gold centred Globes on it too ...
That is freaky.. although these are big n little Simmons (10 and 5 inch), soon to go for something more modern and legal.

The car is exactly as he bought it, and that rear tail panel is actually silver. The car is a Fairmont with GS Rally pack. The grille is wrong for it as it should be a GT type with 4 headlights. Original colour is Outback Bronze, which I quite like. It's not one of those horrible 70s vomit colours.

I also have a GS coupe, but it's the one I grew up with since 2 yrs old. I inherited it as a basket case project from my dad when my parents split in the early 90s. Was Polar White with horn car stripe up the pillar (metallic gold, also the tail light panel done the same). 302, 4 speed, green velour on white interior. Aunger hotwires 14x7, looked like bloody cheese cutters on the rear.

Hasn't changed in any way since rego ran out in 89. One of those "one day" projects

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