Cutting out when warm

[jusm]

Hi Guys,
Just got my refurbished distributor back from Jeff at Advanced Distributors. I've got to say it looks brilliant (polished) and feels tight as a drum. Car started smoothly first go and seems happy running at anywhere between 12-16 BTDC. I'm yet to get it fully warm so haven't set final timing yet.

The reason for this is it cuts out now its warmish.. ie.. if I was to start it now (semi warm) it would idle beautifully at about 800 rpm for about 10 seconds and then stall instantly.. no spluttering, just instant stall.

I have new plugs, distributor, dist cap, leads and coil, so its not spark. New fuel pump and fuel filter is about 1/4 full, so not lack of fuel.

Any ideas?

I really should have left this for the weekend but was pretty keen to get the car going again after a few weeks layoff..

Cheers and thanks in advance!
Justin

[flying farmer]

I would suspect a fault in the new dizzy. You could try refitting the old coil and king lead to see if the problem is there.

Is it an electronic dizzy?

If so is the coil matched to the electronic ignition system, with or without ballast resistor?

To eliminate wiring loom faults run a temporary feed from the battery to the ignition system.

If it still cuts out this would pretty well narrow it down to the new dizzy.

With an instant cut it is unlikely to be a fuel problem.

Neil

[wilf]

Coil. I got through 3 before I found one that worked when hot. Just because it is new does NOT mean it is good. Get another and swap it in immediately you get the fault to prove it. TBH, it is always worth carrying a spare anyway, and they aren't exactly a Kings ransom.

[jusm]

Hi Neil,
Its electronic and matched to the coil (both Accuspark). Wondering why if it fires up and idles well at cold that it would be the distributor?

Cheers
Justin

[jusm]

Coil. I got through 3 before I found one that worked when hot. Just because it is new does NOT mean it is good. Get another and swap it in immediately you get the fault to prove it. TBH, it is always worth carrying a spare anyway, and they aren't exactly a Kings ransom.

Hi, yeah they are all generic chinese under various names these days, as are the electronic ignitions. Might swap back to the original coil and see how I go.
Are the Lucas coils made in England?

Cheers
Justin

[Staggard]

I'am with Wilf try changing the coil ( Sorry to be cheeky but is anything made in England now ) you would know if it was a fuel problem check the filter or whip off the pipe when it cuts out

[jusm]

I'am with Wilf try changing the coil ( Sorry to be cheeky but is anything made in England now ) you would know if it was a fuel problem check the filter or whip off the pipe when it cuts out

Well you guys still seem to manufacture a bit.. here in Oz, all we do it dig ore out of the ground and ship it to China to make cheap electronic ignitions and coils!

Coil sounds like a cheap and preferred solution. Will follow it up on the weekend.

Cheers guys.

[GDPR]

Are you sure it's the car? Do these breakdowns occur close to pubs (as mine frequently do )?

[milothedog]

Are you sure it's the car? Do these breakdowns occur close to pubs (as mine frequently do )?

I'm not sure if you are confusing the issue here with you breaking down or the car

Ian

[jusm]

Are you sure it's the car? Do these breakdowns occur close to pubs (as mine frequently do )?

ha, that would mean getting it out of the driveway.. I can only dream!

[jusm]

ok, so I've gotten off my bum and figured out how to use a multimeter. I'm learning a lot from this experience.
So far I have confirmed.
Battery 12.5v, and coil 6v. So this means the ballast is in place.. all good.
The coil gave resistance of 2.3 across the terminals. A bit high? I thought it should be closer to 1.5.
On checking for spark at night. I can see a very faint spark which I missed when checking during the day.
The spark is exceptionally weak and just visible at night and I'm led to believe it should be bright and visible during the day.

So.. weak spark means? I have a new coil and accuspark ignition unit on the way just in case and as a back up.

Cheers
Justin

[V Mad]

Hi Justin
I wonder if you might have a non-ballast coil in there, they measure about 3 ohms. When you got 6v across the coil, did you short the coil neg to chassis first? (thats the most reliable way of checking ballast/coil).

If ballast and coil are equal resistance you should get half battery voltage in this test.

[jusm]

Hi Chris, yes I did. When I got 6v I tested it this way:
1. Check voltage of battery with volt meter and make a note
2. Remove the wires from the negative side of the coil (negative earth cars)
3. Connect a temporary wire from the negative terminal of the coil to earth
4. Turn ignition on (nothing else switched on)
5. Now check the voltage on the coil, put red probe on + side of coil and the - probe to earth
6. If the reading is less than 80% of battery voltage there is probably a resistor in the system. If it is more than 80% you probably have a standard system

I've certainly got the right coil. Its the accuspark blue. "12 Volt High power Sports Coil 1.5 ohms resistance suitable for Ballast ignitions. Suitable all V8 Models "

Tomorrow night I will run a feed direct from the positive side of battery to the positive on the coil and see if that improves the spark and hopefully starts it. The current feed is coming from the inertia switch feed.

Cheers
Justin

[jusm]

sorry, the feed is not coming from the inertia switch.. confusing my coil and distributor!
anyway, will bypass the ballast by feeding directly from battery to coil and see how i go. Dont know what it means if that works though..

[V Mad]

OK it sounds like you have proved the ballast is there and you have the right coil. The next test you could do is measure the Coil+ voltage during cranking; that should be equal to battery voltage. That will prove that the ballast is being bypassed while starting.

I assume you have a good 12v feed to the accuspark red lead?

Then next area to look at is HT leads and distributor.