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Intermittent Ignition problems


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Evening all.

 

Been a while since I've posted, and still yet to get to my first TR meet, need to make the car reliable enough to get there first !

 

So, problem, every now and again the ignition dies. Just goes, and I roll to a halt. Leave it a minute or so, starts straight off, and off I go again. Or I open the bonnet, waggle the connections, and off we go. Thought process deduces that I have a bad connection or even a bad earth, so I will go through the system next and have a look.

Before I do though, a question. I have a Lumenition setup that all came on the car when I bought it, and there seems to be a stray wire, as shown by 'A' in the photos. Anyone have an idea if this should be connected to anything, such as the -ve or +ve of the solenoid ? Stab in the dark I know, but thought I'd ask. Best sort it as I've sold my regular transport now, the TR6 is my daily drive.

 

Cheers !!

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Hi,

not sure about the spare wire it could be the original that the luminition replaced just a guess. As for your intermittant ignition problem I had the same thing happening on an old VW it took me ages to solve it.

It turned out to be a faulty Ignition coil change it never had any more trouble

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Hi mart160plus,

 

Suggest you look through the archives for Lumenition. My personal experience is that it is a pile of cr*p - but there are others out there who have had no problems with it - so to formulate a balanced opinion check the archives; then you'll find it really is a pile of cr*p.

 

I have had 2 failures exactly as you have described so I suggest you replace with either Newtronic (sadly now owned by the people that make Lumenition) :( or Pertronix (Aldon).

 

The spare wire is probably, as tinman says, a wire that the Lumenition replaced, but you need to get hold of a wiring diagram. My wiring diagram tells me that the wire originally on the +ve side of the coil is white and comes from the fusebox. Judging by the yellowy colour of the insulation on the spade terminal this looks like an original wire. If it goes to the ignition switch via the fuse box and there are green wires on the other side of said fuse, then it's likely to have come off the +ve side of the coil. I don't recommend putting it back on the coil as it's probably been removed for a reason - it's unlikely to be causing your problem. I'm sure others on here will provide you with the original Lumenition wiring info.

 

Ray

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Hi Mart

 

Looks like a ballast resistor connection. Goes to the positive side of the coil. Something to do with getting a better spark during cranking, fitted on post '73 cars. A search on "Ballast resistor" in the archives should give you all the info you need. Not sure how compatible electronic ignition systems are with these.

 

Might do a search myself :lol:

 

Dave

Edited by davehop
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Hi Mart

 

Certainly looks like the unused ballast resistor wire on a post 1973 TR6 see http://www.advanceautowire.com/tr2506.pdf for TR6 circuit diagrams various years (they are for the USA cars so be careful). My TR6 also has the white/yellow wire disconnected and replaced with a white wire 12V with ignition on, see photo. I also have a Luminition set up - Magnetronic Ignition System MTK005 which I fitted soon after finishing my rebuild three and a half years ago. Despite what Ray says I have done nearly 10,000 miles with absolutely no trouble (tempting fate here but do carry points etc in glove box!) ignition system performs very well. Even have Lumenition leads as well. Looking at my connections I have a red wire from coil +ve and a black wire coil -ve to the Lumenition module, you do not appear to have the red wire? Have a look at the attached scan of wiring diagram.

 

Hope this helps

 

Regards

 

Bill

 

 

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I have a Lumenition setup on my V8 and it has always worked perfectly, even when I broke one arm off the chopper and epoxied it back on (it's still like that). When funds permit, I'll put one on the TR.

 

Stops then restarts? Sounds like the ballast or the primary windings in the coil.

 

In elder days of yore, ignition systems just used a 12v coil with a 12v feed from the battery via the ignition switch. This is OK when the engine's running, but, during starting, the starter draws a heavy current leaving less energy to fire the plugs. The result is a weaker than normal spark and sub-optimal starting. This is worsened by colder temperatures and/or a worn starter motor which draws more current .

To overcome this, ignition systems were developed with a lower voltage coil, usually 9v. To run a so-called 'ballast coil', the 12v ignition feed runs through a ballast resistor, (big white porcelain block) reducing it to 9v at the coil. To assist starting, a separate 12v feed from the starter solenoid bypasses the 9v ignition feed, temporarily giving the 9v coil a 12v feed. The result is a supercharged spark for starting. As soon as the engine has started, the 12v feed is cut and the coil reverts to the 9v ignition feed.

 

When the ballast starts to fail, it goes 'open circuit' and initially it works when cold, but fails when hot. Then is OK again when it cools. Eventually the faulty ballast damages the primary windings of the coil, so that if the ballast is replaced, it in turn becomes damaged again. Or someone removes the ballast, leaving the 9V coil permanently overloaded with a 12v feed, which it copes with for a while.................

 

So you may have a faulty coil or ballast or both.

I would renew the coil, and the ballast if you have one. If you have a standard 12V coil, I would fit a ballast coil and a ballast, for better starting.

 

This is cheap enough not to bother with lengthy diagnosis to check that it is indeed the problem, but if you are intent on checking then you need to ambush the fault while it's hot, so carry a voltmeter around with you, and next time it grinds to a halt, leap out and immediately check for voltage at the coil. There won't be any....

 

Still, at least the TR is light enough to push :lol: You should try pushing my Landrover :o

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I experienced a number of failures as I was driving home in my '6 yesterday evening. Fortunately I was only 300yards from home but it took me about 5 attempts going 50y each time. Interestingly, the day before when I went to start the car nothing happened - I started thinking about solenoid, starter etc, but then everything burst into life and I remembered seeing something recently saying the ignition switches are a little flakey, so I put it down to that and decided to carry on regardless. However, as it was lashing down last night and temporarily stranded so close to home I did start to reconsider this decision. Anyhow, I think my problem could be the switch itself, once the car drifted to a halt it restarted immediately.

 

On second thoughts, I suppose the fuel gauge could have been faulty - showing just under half a tank when it was really empty, but i doubt it. Just looking at buying a replacement switch now, but while my wallet was out started thinking about electronic ignition too, hence a quick browse of the forums to judge which is best.

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  • 2 weeks later...

Try checking the ignition switch. I have had two fail on me recently. The first was due to a worn wiper that would break contact after a few miles. But the action of moving the key to switch off and on again brought it back for another few miles ( weak spring?). The second built up a little bit of 'sprue' that forced the wiper away from the contact and totally prevented an engine start. These switches are very poorly made. Take it out and put a meter on it to check for any contact resistance. It should show a low ohmic value that should remain constant even when the terminals are slightly stressed. I don't think it is due to anything other than poor manufacture. I doubt that it's the coil as once overheated it should sustain the fault condition until it cooled down. The electronic spark amplifier would be a logical choice due to it's apparent complexity, but think Lucas every time and you will not be far wrong. I sent my unit back to Newtronic for testing. It was cleared of any fault, then I discovered the ignition switch was the culprit!

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Mart

If you have still got the parts would it not

be an idea to revert back to points & condenser

and see if it runs ok, at least you would have

proved wether or not its the Luminition.

You can always put it back again or replace

it if it proves to be faulty.

 

Bob

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