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queeniee
19-10-08, 03:49 PM
Recently, after driving for 150 miles, I had a total ignition shut-off, lasting about 1 second or less, dropping the rpm to zero. Then immediatly and spontaneously, the ignition re-fired normally (I did not had to use the starter) and the engine ran as usual. But during my trip, this condition deteriorated: the periodicity of the problem increased and I reached home with ignition cutting almost every 300 yards duting the last miles.
My set up uses Mallory:
A Mallory Hyfire VI (MAA685)
A Promaster ignition coil (MAA 29440)
A Breakerless distributor (MAA-5755301)
A ballast resistor
All these components are only 6000 miles old including the ignition wires.
The engine always starts fine either hot or cold.
The ignition problems occured without no overheating conditions.

Yesterday, I changed the Mallory Hyfire VI, replaced it with an identical new one. I also tightened some contacts between the wires and the coil. I test the engine for 3 minutes at idle with no problem.
This sunny morning, I thought to go for a test ride. But after 300 yards, I had the bad surprise to observe 5 ignition cut-off!!! So, the problem does not seem related to the Mallory ignition control box.
Have you got ideas about what I should check now? The ballast resistor? It seems difficult for me to test it since the problem has a very short duration (less than 1 sec)?
Or what else would be the best thing to test before I change all the electrical parts from A to Z?
Your help would make me and Cobra happy.

wilf
19-10-08, 04:30 PM
Try swapping the coil next.

Is it an oil-filled type, if so, how is it mounted?

queeniee
19-10-08, 04:49 PM
Try swapping the coil next.

Is it an oil-filled type, if so, how is it mounted?
It is an oil-filled type and it is flat mounted vertically. Its mounting is the same as the previous years when I had no ignition problem.
This is not a too costly part (70$) and what you suggested corresponds to what I thought to try next. And maybe the ignition wire going from the coil to the distributor cap?

Purple AK
19-10-08, 05:07 PM
Hi Queenie.
As the cut only lasts a second or so, It doesn't point to it being heat related (if it were it wouldn't cut back in untill it had cooled down) therefore it looks as though it is a faulty connection. You could try running the engine, and tapping the coil, dizzy, ballast and any wiring with a screwdriver handle to see if you can pinpoint where the problen lies.

queeniee
19-10-08, 05:21 PM
Hi Queenie.
As the cut only lasts a second or so, It doesn't point to it being heat related (if it were it wouldn't cut back in untill it had cooled down) therefore it looks as though it is a faulty connection. You could try running the engine, and tapping the coil, dizzy, ballast and any wiring with a screwdriver handle to see if you can pinpoint where the problen lies.
I do not accuse heat either. My engine has a very high vibration level (everything vibrating) but your suggestion is the less costly one. I shall try tomorrow when I go back to my garage which is at the other end of the town.

queeniee
19-10-08, 08:24 PM
I forgot to mention that this occurs either at idle or at cruising rpm, either running on a flat surface, or climbing at full power or when descending in neutral gear. This is really electrical related. I start also of thinking about an intermittent cut off in the ignition switch. Could this be possible? I am a bit reluctant about removing the dashboard and looking behind (or crawling under the dashboard and using a mirror...).

wilf
19-10-08, 08:53 PM
It is an oil-filled type and it is flat mounted vertically. Its mounting is the same as the previous years when I had no ignition problem.
This is not a too costly part (70$) and what you suggested corresponds to what I thought to try next. And maybe the ignition wire going from the coil to the distributor cap?

Yes - that particular HT lead would be my next check.

Then I think it will be to check the absolute continuity on the feed AND earth sides of the ignition box.

Luck in your search for what I suspect will be a "mechanical" electrical problem.

Don't forget the distributor cap and its central electrode, either.

Purple AK
19-10-08, 08:56 PM
I forgot to mention that this occurs either at idle or at cruising rpm, either running on a flat surface, or climbing at full power or when descending in neutral gear. This is really electrical related. I start also of thinking about an intermittent cut off in the ignition switch. Could this be possible? I am a bit reluctant about removing the dashboard and looking behind (or crawling under the dashboard and using a mirror...). It is possible. You could Hotwire the Ingition box direct from the battery or known good power source to check/illiminate the switch. Ford switch connectors are notoriously bad!!

bc_suv
19-10-08, 09:02 PM
Hi Queenie,

It might be worth double checking the engine earth straps as well....

Good luck tracking this one down..

Regards,

Brian.

queeniee
20-10-08, 06:54 AM
Thanks to everybody for your serious answers; I am afraid that a "mechanical" electrical bug is a real pain to locate.
As it can always be useful, I shall make an order of a coil, wires, distributor cap, ignition module,ignition switch.
I stored my old spark plug wires somewhere (they were only old but operating OK). If I can find them, I shall easily try to replace the actual one (the main wire).

gilby
20-10-08, 11:03 AM
have you checked this inside of the cap for corrosion. I've got an MSD ignition with some trouble with mist inside the cap ( we live in france and in this season you have a lot of humidity!) my engine did the same , cutting at the worst time(traffic light , overtaking!) . When he starts again does the engnition seems to be out of tune? (backfire?)

snakebite
20-10-08, 12:34 PM
Are you sure its electrical and not fuel related? could it be fuel line filter blocking up?

wilf
20-10-08, 08:33 PM
Steve - the fact that the tacho drops to zero during the ignition cutout indicates that it is losing spark, and that the ignition box itself is ceasing to operate for some reason. My money is on a dodgy live feed/earth to that ignition box somewhere -very difficult to track down.

Purple AK
20-10-08, 08:37 PM
Steve - the fact that the tacho drops to zero during the ignition cutout indicates that it is losing spark, and that the ignition box itself is ceasing to operate for some reason. My money is on a dodgy live feed/earth to that ignition box somewhere -very difficult to track down. My Money is still on the ignition switch/connectors to it ;)

tonym
21-10-08, 10:23 AM
My Money is still on the ignition switch/connectors to it ;)

If the ignition switch is faulty wouldn't ALL electrics fail, I.E. other gauges , lights etc?

snakebite
21-10-08, 01:27 PM
Steve - the fact that the tacho drops to zero during the ignition cutout indicates that it is losing spark, and that the ignition box itself is ceasing to operate for some reason. My money is on a dodgy live feed/earth to that ignition box somewhere -very difficult to track down.

Totally agree with what you are saying Wilf, symptoms are pointing that way. The only reason I mentioned fuel starvation was that when I re-fitted the filler pipe to the tank a sliver of rubber was cut from the inner edge and fell into the tank. The rubber made its way to the fuel filter and every time the tank emptied to halfway the engine stopped dead after, as you pointed out, with a little hesitation (obviously the weight of petrol up until half empty kept it going), re-fill the tank to full and off she went with no hesitation. Either way a sod to find......good luck Queenie

westborne
22-10-08, 03:50 PM
I remember that - we were filling from our spare fuel cans !!!

Neil O
22-10-08, 05:16 PM
I remember that - we were filling from our spare fuel cans !!!

What spare fuel?:(


Queenie, sounds like a total lecky loss. As said already.

wilf
22-10-08, 05:26 PM
Of course - I forgot - Neil would be a veritable expert when it comes to a lack of sparking............:twisted:

Neil O
23-10-08, 09:12 AM
Of course - I forgot - Neil would be a veritable expert when it comes to a lack of sparking............:twisted:
Unfortunately, yes, I have had a "learning" in matters of the spark.:(

My problem was different to Queenie's though. It would run for a while, then cut out and not start again for a while.
It was the coil.

queeniee
25-10-08, 08:25 AM
Totally agree with what you are saying Wilf, symptoms are pointing that way. The only reason I mentioned fuel starvation was that when I re-fitted the filler pipe to the tank a sliver of rubber was cut from the inner edge and fell into the tank. The rubber made its way to the fuel filter and every time the tank emptied to halfway the engine stopped dead after, as you pointed out, with a little hesitation (obviously the weight of petrol up until half empty kept it going), re-fill the tank to full and off she went with no hesitation. Either way a sod to find......good luck Queenie
I do not know yet who will win the bet but I can confirm that it is not the fuel filter and that it is electrical. The main wire solid core (from coil to distributor) seemed reduced in diameter, there was a bit of corrosion on the metal "clamp" of the core (on the distributor side). I still wait for the wires coming from USA and I have already borrowed a crimping tool to install brand new wires.

queeniee
09-11-08, 01:24 PM
I have changed the main ignition wire (from the coil to the distributor head) and after 100 miles of road test, I can say that those who thought it was the guilty part have won their bet.
I first lost time changing the Mallory VI, this was my N 1 possible guilty part but I was wrong. Changing the wire was less costly and revealed to be 100% efficient. I have been lucky to win at my second curative action. The core of the old wire had a sad look that appeared only when I removed it from its rubber boot.
Thanks to everybody who replied to my post/

wilf
09-11-08, 03:09 PM
Good news, thanks for letting us know.