Coming to a complete stop

Discuss Electrical problems here.
Forum rules
By using this site, you agree to our rules. Please see: Terms of Use
Post Reply
MontyMorris68
Minor Friendly
Posts: 13
Joined: Thu Jun 18, 2020 10:34 pm
MMOC Member: Yes

Coming to a complete stop

Post by MontyMorris68 »

Evening all,
I have had the car fully rewired by an auto electric due to fire in the engine bay which melted all the wiring around the control point box and the dynamo
Since then I have had some good runs out in the car with no issues until the couple of months and the furthest I have got is 10 miles, then it looses power and comes to a complete stop. The first time it happened I found one of the wires was loose at the coil and put it back on and all seemed fine until the next run (and only got 3 miles) and then it started back firing badly and then again completely nothing. I was told to replace the coil as it was red hot (and you could hear the liquid moving about inside it) leads, condenser and points and hopefully that would be the problem sorted.
I am reluctant to go any further than 3 miles without this happening again and having to phone breakdown (glad to have it in my insurance policy).
Can anyone suggest what else I should be checking to rectify this most annoying problem, thanks in advance for any help.
Morris
islecastle
Minor Friendly
Posts: 40
Joined: Wed Dec 01, 2021 10:19 am
MMOC Member: No

Re: Coming to a complete stop

Post by islecastle »

You don't say if you have replaced the coil. I would do that and see what happens, i.e. your problem soumds to me to be coil related.
1973 Ford Cortina Mk3
1967 Morris Minor 1098 Convertible
1978 MGB GT
2000 Mercedese Benz SLK 230K
ManyMinors
Minor Legend
Posts: 2753
Joined: Tue Nov 11, 2014 9:41 am
MMOC Member: No

Re: Coming to a complete stop

Post by ManyMinors »

The most important thing when replacing parts, is to purchase good quality items. There is SO much cheap imported junk on the market. Deal with a reliable and reputable supplier such as "The Distributor Doctor" when sourcing such parts and you shouldn't go far wrong :wink:
MontyMorris68
Minor Friendly
Posts: 13
Joined: Thu Jun 18, 2020 10:34 pm
MMOC Member: Yes

Re: Coming to a complete stop

Post by MontyMorris68 »

I have purchased a coil, leads, points and condenser from ESM and it is a Lucas coil.
The coil that was on the car was an auto sparks one.
Thanks for the feedback and help, much appreciated.
Morris
oliver90owner
Minor Legend
Posts: 1655
Joined: Thu May 12, 2016 6:33 am
MMOC Member: No

Re: Coming to a complete stop

Post by oliver90owner »

The ignition system used is quite simple, basic and was used for decades by millions of vehicles until electronic systems superseded the aged and simple electrics.

First of all, do we know that it is an electrical fault? Do we know that it is an ignition system failure? Were any faults found on testing/checking the existing component parts?

Everything has a specification, which is easily verified. Guessing is not the way to go. Simply just replacing a loose connector is not a proper repair. The connectors are required to fit securely with a low resistance. That, alone, could be your problem.

Coils only get hot (and not ”red hot”) if fed with the incorrect voltage, or are low resistance, or simply left connected to live and earth. There is always a reason - usually a simple reason.

First step is to check for spark (or absence of spark) when the fault occurs. Then go from there….
myoldjalopy
Minor Legend
Posts: 2518
Joined: Tue Jan 29, 2013 10:32 pm
Location: Kernow
MMOC Member: Yes

Re: Coming to a complete stop

Post by myoldjalopy »

It will be interesting to find out if any of the new components to be fitted solve the issue. If not, we must take a more logical diagnosis to determine the real cause of the problem.
oliver90owner
Minor Legend
Posts: 1655
Joined: Thu May 12, 2016 6:33 am
MMOC Member: No

Re: Coming to a complete stop

Post by oliver90owner »

myoldjalopy wrote: Sun Jul 24, 2022 2:34 pm It will be interesting to find out if any of the new components to be fitted solve the issue. If not, we must take a more logical diagnosis to determine the real cause of the problem.
Dead right there! It is always better to treat the fault with a logical diagnosis, before guessing and going off in any direction except the right on. A logical diagnosis may only need one check, but sometimes getting on the right trail of the fault may need extra checks - all before rectifying the simple fault. Rarely is there more than one fault to fix.
simmitc
Moderator
Moderator
Posts: 4718
Joined: Thu Apr 15, 2004 9:43 am
Location: Essex
MMOC Member: Yes

Re: Coming to a complete stop

Post by simmitc »

IF it is really back firing, then that could be a weak mixture (lack of fuel) or an ignition problem. You need to establish which it is. Can we have a bit of additional background?

What caused the original fire "around the control point box"? Do you have any pictures of the damage?

Has the electrician fitted a new ready made loom correct for the car, or made one, or repaired the damaged one?

Now to diagnosis. Take the car for a run until it stops. Remove and refit the fuel cap and try to start again. Does it run? A blocked air vent could cause a vacuum in the tank and a lack of fuel at the carb.

Try tapping the fuel pump. Does it suddenly start clicking? Stuck points (in the pump, not the ignition) could cause a lack of fuel at the carb.

We'll leave the carb alone for a while, it was just the first two tests to check as soon as the problem occurs.

Remove the central HT lead from the distributor cap and wedge with the end about 1/4 inch from the block. Turn the engine over, do you see a good regular spark between the lead and the block? What colour is it?

No spark = ignition problem, good spark means probably rotor arm.

Coils do get hot in use, and a liquid filled coil should have liquid inside it! My gut feeling is a faulty condenser, but let's prove each step. Never change everything at once as you will never know what was wrong, always one step at a time. This site has an old adage that "it's never the coil", and, whilst sometimes it is the coil, the adage is usually correct.
les
Minor Maniac
Posts: 8739
Joined: Tue Feb 12, 2002 12:00 am
Location: kent
MMOC Member: Yes

Re: Coming to a complete stop

Post by les »

Your suggestion of a comprehensive diagnosis procedure should be music to olivers ears ! :D

cyrus
Minor Friendly
Posts: 67
Joined: Tue Oct 12, 2021 6:29 pm
MMOC Member: Yes

Re: Coming to a complete stop

Post by cyrus »

The only time I had backfiring problems was with a cheap condenser, although you say you have Lucas stuff would replace anyway as it's cheap to do so. Drew quite a crowd at the time as no-one had heard backfires in about 40 years. :D
Only time I had a hot coil was on a ferry and luckily a visiting rugby team pushed the van off the ferry and managed to bump start it, got a replacement coil and all was well. I know it's never the coil.... but sometimes it is.
I have also had a problem with the coil in that the peened contacts on the coil can sometimes be a bit iffy, what with dirt and oil contamination and the rivet working loose it sometimes makes a bad contact. This was solved by cleaning and tapping the rivet with a centre punch. Check there is continuity between the rivet and the tag.
oliver90owner
Minor Legend
Posts: 1655
Joined: Thu May 12, 2016 6:33 am
MMOC Member: No

Re: Coming to a complete stop

Post by oliver90owner »

Only time I had a hot coil was on a ferry and luckily a visiting rugby team pushed the van off the ferry and managed to bump start it, got a replacement coil and all was well.

From the above, it might appear that the ignition was left switched on and the ~4A drain for the crossing duration was enough to discharge the battery? Likely the coil was still OK, as the vehicle was restarted?
cyrus
Minor Friendly
Posts: 67
Joined: Tue Oct 12, 2021 6:29 pm
MMOC Member: Yes

Re: Coming to a complete stop

Post by cyrus »

oliver90owner wrote: Sun Jul 31, 2022 7:48 am Only time I had a hot coil was on a ferry and luckily a visiting rugby team pushed the van off the ferry and managed to bump start it, got a replacement coil and all was well.

From the above, it might appear that the ignition was left switched on and the ~4A drain for the crossing duration was enough to discharge the battery? Likely the coil was still OK, as the vehicle was restarted?
I'm not sure, don't think I left the ignition on and the ferry crossing was only about 500 yards across a river anyway. The van just about started with a very fast bump start and got us back to the campsite we were on but after that wouldn't start again and the coil just got hot. Managed to buy a new coil locally (this was many years ago) and the van was fine after that. Never had anything like that happen to any other of the 5 minors I have owned over the years. Kind of assumed that the coil had suffered some internal problem with the windings, in fact I seem to remember that it had been over clamped by someone and the coil body was a bit distorted on the underside.
kevin s
Minor Legend
Posts: 1376
Joined: Tue Mar 26, 2013 8:20 pm
Location: Chelmsford, essex
MMOC Member: No

Re: Coming to a complete stop

Post by kevin s »

Is it possible in the re-wiring that the coil has ended up wired back to front? Especialy if it has gone from positive to negative earth.
User avatar
geoberni
Minor Legend
Posts: 3566
Joined: Fri Aug 04, 2017 11:19 am
Location: North Leicestershire
MMOC Member: Yes

Re: Coming to a complete stop

Post by geoberni »

kevin s wrote: Mon Aug 01, 2022 10:20 pm Is it possible in the re-wiring that the coil has ended up wired back to front? Especialy if it has gone from positive to negative earth.
All that does is result in a weaker spark and overheated plugs, due to the spark jumping plug body to centre electrode.
I don't think it will damage the Coil, it's only a transformer when all said and done.
But I guess it's worth looking at, it'll only take a few seconds.
Basil the 1955 series II

Image
oliver90owner
Minor Legend
Posts: 1655
Joined: Thu May 12, 2016 6:33 am
MMOC Member: No

Re: Coming to a complete stop

Post by oliver90owner »

At least a few posts making suggestions, since the usual unhelpful guesser’s post.

I can still not quite understand how the van battery became so depleted of charge during a 500 yard crossing. Although that could be down to a near-end-of-life item, or under-watered, if cells were of that type. Another option could have been that the lights were left on, too? There is only about a 50% chance (maybe more) of the points being closed if the ignition circuit had been left on. It may only need one dead cell in the battery to make it struggle.
Post Reply