V8 - lumenition to powerspark distributor wiring help please

pardonthewait

pardonthewait

Member
Hello,

I've tried a search as I feel quite stupid asking this question, but I'm new to classic cars and the P6 and learning as I go on a broken car so I struggle a bit.

My 1972 P6 V8 which I bought a couple of weeks ago has a starting problem - i.e it won't. It did, but would occasionally splutter and die, we've replaced the battery, replaced the coil, and fuel is getting to the carbs. Weak spark. With help from others and by googling I am reasonably sure it's the Lumenition system that was fitted to the car that was at fault, and the upshot of this is I've bought a Powerspark electronic distributor, HT leads and coil and a timing gun.

My problem is the wiring - I'm a little unsure on a couple of points and some help would be much appreciated.

The dizzy has a 3-2 converter plug and a white and red lead coming from that. There's also a brass tab for a spade type connection. The red/white wires go where - to my coil I gather? What goes to the spade connection? Low tension lead?

I know I need to ditch the ballast resistor wire, and I gather that I can take a switched feed from some other item from the fuse box (or in the engine bay?). All that went to the lumenition box was a red wire that I have traced back to the fuse box but can't see exactly where it goes apart from into a bit of chocolate block and then into the fuse box but I can't see to where. Basically that red wire and a green wire passed by the lumenition box and goes right to the front of the car, to the fan I think - that was where I managed to chase it to. The red and brown wires from the lumenition unit were both connected to that red wire. The lumenition box was then connected to the coil negative post and to the distributor by a three wire plug.

Basically aside from connecting the dizzy to the coil I'm lost past that point.

I know this is a really stupid question but I'm struggling to find much information on the Powerspark website, there are no instructions and I know that a couple of you guys run the Powerspark distributors but couldn't find the answer to this question through searching and I really hope you can help!

I think I am ok on the timing front, I've managed to work that out hopefully - it's just wiring all this in correctly, I'll be doing it with my dad on friday/saturday and I'd like to be clued up in advance!

Any help much appreciated, sorry for long rambling post. I'm willing to learn!
 
yes to the coil, and spade is earth iirc. I have this setup on my car and can get you a picture when its light tomorrow hopefully...

I had trouble with the tooth on the bottom of the dizzy not going home correctly into the oil pump spindle. You may want to try it on a spare spindle to make sure before you put it in...

Once I'd disconnected the lumenition on mine it became pretty obvious as to what was needed and what wasn't. I ended up just removing anything that went through the lumenition pretty much. I can again give you a pic tomorrow.

Rich
 
That would be amazing, thanks very much.

Where did you take a feed from the bypass the ballast? And where did it go to?
 
Hi rich
You chaps must be extremely unlucky when it comes to lumenition.
All my p6s/ mini have it /the one on my dads 3500 been on since 1974 .
Still some must go wrong.

clive.
 
I might be completely wrong! But it's just where it's led us at the moment. I figured the new distributor would be a good idea as its a bit of a clean slate in terms of the ignition, and if it doesn't fix the issue... Well at least it's been renewed.

I really hope it does though, I'll be pulling my hair out if not!
 
pardonthewait said:
My problem is the wiring - I'm a little unsure on a couple of points and some help would be much appreciated.

The dizzy has a 3-2 converter plug and a white and red lead coming from that. There's also a brass tab for a spade type connection. The red/white wires go where - to my coil I gather? What goes to the spade connection? Low tension lead?

I know I need to ditch the ballast resistor wire, and I gather that I can take a switched feed from some other item from the fuse box (or in the engine bay?).
Click to expand...

Hi,

The instructions you need are here:

http://www.simonbbc.com/distributor-install-helper

You're right that you need to ditch the ballasted supply from the fusebox to the coil +ve....but just disconnect at each end and leave it in place in case you ever want to revert.

For the new 12V supply:

You can piggyback to an existing ignition switched supply in the engine bay, say the washer feed, but if the supply to that component fails you'll also lose your ignition supply. No fun on a dark night on a lonely country road!

At the fusebox terminal #19, you'll see 3 x white cables. One of these is the feed from the ignition switch output, one is the feed up to the tacho/panel warning lights, and the third is the the feed to the coil +ve through the inline ballast resistor. Disconnect all three at the fusebox, and you can find out which is the third cable using a multimeter and an assistant. Disconnect the battery, and reconnect the first two cables at terminal 19.

In place of this third cable, run your new supply from terminal 19 through the bulkhead grommet to the coil +ve. Reconnect battery and test.

Hope that helps.

Stan
 
I took the lumenition off mine because the lucas dizzy had loads of play in it. A new one was really the only sensible route, and these were the only sensibly priced thing i could find at the time. Mine's an S1 so the fusebox is in the engine bay so it has a 12v feed straight from there.
 
That does help enormously, thank you. I have two more stupid questions!

It lists red to positive and black to negative, I have red and white so I presume I just go red to positive white to negative?

And with setting the timing, the crankshaft marker is at (or very close to) the TDC marker - is that marker no1 cylinder TDC specifically?
 
Hi again,

Yes, red to positive, white to negative. They don't make it clear, do they? :roll:

Yes also, the pulley timing marks relate to No.1 cylinder....front cylinder in the left-hand bank - as viewed seated in the driver's seat.


Good luck with the install....let us know how you get on!

Cheers,

Stan
 
rockdemon said:
I had trouble with the tooth on the bottom of the dizzy not going home correctly into the oil pump spindle. You may want to try it on a spare spindle to make sure before you put it in...
Click to expand...

Having a bit of trouble with this currently. I can only get the dizzy to fully locate onto the oil pump spindle in one orientation, which isn't pointing to where the manual says my no1 cylinder plug should go to on the cap.

How do I get around this? Is the position of the no1 cylinder important or is it just important in relation to the other cylinders? Apologies if that's a stupid question.

Otherwise can I rotate the oil pump spindle somehow?

Thanks :)
 
pardonthewait said:
Having a bit of trouble with this currently. I can only get the dizzy to fully locate onto the oil pump spindle in one orientation, which isn't pointing to where the manual says my no1 cylinder plug should go to on the cap.

How do I get around this? Is the position of the no1 cylinder important or is it just important in relation to the other cylinders? Apologies if that's a stupid question.

Otherwise can I rotate the oil pump spindle somehow?

Thanks :)
Click to expand...
Had exactly the same recently. See the topic below to see what I had done:

Refitting the dizzy

Basically the oil pump drive had moved round a bit, which meant when it mated the rotor arm was in the wrong position. I turned the oil pump to the correct position using a long screwdriver, and then all was fine again :p

Hope this helps.
 
I actually called power spark and be said it doesn't matter - just start from where the rotor arm is pointing. Is that ok or should I re-do it?

Aside from that, my fuel pump now isn't working! It was powered by a wire that went through my Lumenition box but now that's out of the picture I just carried that wire on to the fuel pump. I guess best bet is to run a new feed to it from the fuse box? Can I take it from the same place I took the coil positive from?

Thanks for continued help all, I wouldn't have the faintest idea what to do otherwise.
 
Fuel pump works, when connected straight to battery, so it's alive. Where should I take a feed from? I actually just spliced it in with the positive going to the coil, and got nothing on ignition. But I've tested that feed and there's continuity from the fuse to the positive post on the coil. Im a bit unsure what I'm missing but sure there is something!
 
pardonthewait said:
I actually called power spark and be said it doesn't matter - just start from where the rotor arm is pointing. Is that ok or should I re-do it?
Click to expand...
With the pointer on the engine indicating close to TDC, (on the compression stroke of No.1 piston), the rotor arm also needs to be firing on No.1 spark plug:

IMG_5117.jpg
IMG_5120.jpg


If the rotor arm it is pointing anywhere else, you will have problems.
 
What I mean is if I plug my leads in according to where my rotor arm is pointing at no1 TDC, would that be ok?

Also I have a problem that is fixing me completely at the moment.

I've been testing the voltage at the fuses and I only get any reading at all from two of the fuses - the first two on the left which are marked battery control and hazard lights according to the fuse box cover. Everything else gives me nothing at all even with new fuses.

I know the fuse boxes are a bit notorious - would this be how an issue could present? The Lumenition box was attached to a brown wire but that disappears back up into the dash so I can't currently see where it goes, not direct to the fuse box.

However headlights etc and radio work. I can't tell what these are wired to.

Bite the bullet and replace the fuse box, or am I missing something?

Oh. One of the fuses was covered in tin foil - the 19 one. The fuse however is good so no idea why previous owner had done that.

Totally lost at the moment and feeling pretty out of my depth.
 
Have you got a wiring diagram, its in the Handbook and Workshop manual ? You should be able to work out which wire is which from that. As far as I can see, on the main fuse box, only one fuse is live without anything else switched on, that being the Battery control as you mention . All the others are such as headlight , side lights heater etc., and are only live when they are switched on. An original brown wire will be live all the time, as it is connected to the battery . As others have mentioned you need a feed from a white wire for the ignition switched feed to your distributer.
This link gives the basic colour coding for wiring on British vehicles of the era .http://www.autoelectricsupplies.co.uk/c ... rder_2.pdf
You will see that wires under the brown heading , are connected so they are live without the ignition and are not fused. Ones under purple are similar to brown but are fused.
The ones under White only work with the ignition on but are not fused and Green are the same but are fused. The wires with these four basic colours are the basis from which all the others stem via switches, relays etc. Blue go to headlights, Red to side & tail etc. There are always exceptions
 
In the fuse box area there are various wires hanging down not connected, some on the drivers side shin bin, the "19" fuse was covered in tin foil when I got the car... I feel very out of my depth with the electrics at the moment. I've been put in touch with an auto electrician who works mostly on classic stuff and is meant to be very good, he's coming on Monday.

It's a shame to admit defeat but with it already being a bit of a state and quite bodged it looks like, I really think I'm only likely to make things worse! My dad admits he's not good with electrics too, so I think it's best to swallow my pride and get help at this point. I've been pretty much banging my head against a brick wall all day and hopefully he can make it right and undo the prior bodges (and whatever unsuccessful work I've done today if necessary).

Looking at the diagram in my manual (which states it's for a 3500s but the 3500 model diagram doesn't seem to match up at all, is that normal? Car is badged as a 3500) seems to back up that the wire I found was the ballast resistor wire. But honestly I'm very lost with wiring diagrams I find them incredibly hard to follow.

Really appreciate the help you guys have given me so far, hopefully once this guy's been I'll be able to get her started again, and properly this time!
 
I'm down Southend way in Essex. However for this one I reckon I'm gonna let this guy loose on it, with any luck he can sort this and point me in the right direction regarding the mess that's under the dash.

There's a lot of stuff I'm willing to have a go at, most things to be honest, but electrics just confound me pretty much and I wouldn't want some poor kind-hearted bugger to come down here and sort it all out without paying them!
 
covering the fuse with tin foil - could it be loose connections a la S2 fuse box problem?

Rich
 
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