QuestionQUESTION: My GT6 MK3 is, I think a 'mixture' of parts,and could have a loom from a n other vehicle,(1)how can I ID the loom?
(2)Although it came with a 12v coil,there is no reason to not suspect that this may have been fitted in error,and although the car runs ok,I would be happier to disconnect the BR,-if I could find it,- There are no signs of a ceramic one,so there must be one within the loom wiring,if so where is it?
(3) Do I just disconnect a wire somwhere and wrap it up or must I loop it through the fuse box?,-dont really want to do that,-just in case! and (4)what damages have been going on unbeknown to me,-am using electronic 'luminition' type,with Aldon 1.5 Ohm Flame thrower coil. Cheers Nick.
ANSWER: Nick,
Let me take them in order:
1) ID the loom? I've seen the loom maker's tags on some looms pulled from Spitfires but I don't know that they're marked with anything to id the loom (model, year, etc). If memory serves, it's on the largest section of wiring under the dash near the fuse block,
Otherwise, how to ID? Well, Triumph kept to the English conventions of using certain colored (or is it coloured? ;) wires for certain functions. And other than the body change, I don't know what differed between the Mk I/Mk2 (or GT6+ in the US) and the Mk3. If you have a manual for the car that has wiring diagrams for all 3 versions that'd be the first place to look for differences.
In the mean time, if all the electrical bits in the car are working (interior lights, gauges, headlights, etc) and there's no obvious extra wiring there's a good chance you've got a correct harness, or close enough.
2) 12V vs 6V coil. Best test? Get a good multimeter. Measure the battery voltage (should be 12.5V or greater). Turn on the ignition and check the voltage at the + terminal on the coil. Then get a friend to bump the starter while checking the voltage at the + terminal on the coil.
On cars with a ballast resistor, in igntion on, not starting you should see roughly 6V. In start mode it should be somewhere between 6V and 12V.
Without a ballast resistor, you'll see the full 12V at the coil ignition on, no starter. When the starter kicks you'll see the voltage drop (maybe 9v?) depending upon battery condition.
3) Don't know why you'd need to disconnect the BR.. what does the electronic ignition system want?
4) I'm purely a points and condensor old school kind of person. Luminition should have instructions (either with the unit or on the website?) that specify whether it should be run purely at direct 12V or with ballast resistor. I'll leave that question to the folks that make their living selling the units.
Hope that helps.
Cheers,
Jim
---------- FOLLOW-UP ----------
QUESTION: Jim,- Its like this,- If,unbeknown to me,there is a ballast resitor connected within the loom circuit,and A 12volt coil is used,instead of a 6v -what would I see on the Multimeter?
24v Perhaps? Nick.
ANSWER: Nick,
The ballast resistor is used to lower the voltage that the coil sees under running conditions. It is wired in series with the coil and is supplied by the ignition switch. What happens is that when current flows through the BR there will be a voltage drop.
The stock coil is something like 3 ohm or 3.5 ohm, so the ballast resistor should have a value in that approximate range. That way the coil sees a 50% reduction in voltage (6V) when the car is running.
To give the car a "kick" when starting, full battery voltage is supplied to the coil from the starter solenoid. Just while the starter is cranking, not all the time.
I was wrong in suggesting testing ignition with the car not running.. with the electronic setups you'll need to measure voltage with the car running.
The coil voltage rating will not affect what voltage you'll measure at the +terminal, that's dictated purely by the car wiring and any BR in the circuit.
So, car running, you'll see either full battery voltage across the coil without a ballast resistor, or something less than full voltage (approx 6V) with a ballast resistor in the circuit. When you crank the car over you should see full battery voltage, keeping in mind the starter will draw the voltage down under 12V typically.
Cheers,
Jim
---------- FOLLOW-UP ----------
QUESTION: Jim,- Here we go again,-As I have said my coil is 12v Aldon flame thrower @1.5Ohms,how should that fit into the mix? if there is a ballast resister present,what reading should I expect??
Also, are we saying that all engines that have a ballast resistor are running with 6volts,and all the engines without a ballast resistor are running at 12v,with a 12v 1.5 Ohm coil.?
AnswerNick,
Regardless of coil installed:
All measured at + terminal on coil:
With Ballast Resistor-
Engine starting approx 12V
Engine running approx 6V
Without Ballast Resistor-
Engine starting approx 12V
Engine running approx 12V
Adjust your wiring/coil choice depending upon what the ignition unit requires.
Cheers,
Jim
