8 replies to this topic

[itscomealongway]

my mini has been running on three cylinders so i replaced, plugs, leads, dizzy cap and rotor arm and it was still running horribly, i got it compression tested in case the head gasket had chucked it, and everything was fine. now back at home the spark plug at cylinder one is all black and after replacing it again, with the help of a friend i have worked out that the spark is very weak and on the way home from the compression test it was stinking of fumes inside the car, any suggestions greatly appreciated.

[Jammy]

Could be overfueling? The number 1 cylinder naturally runs richer anyway, so you'd see the effect of overfueling more pronounced on this cylinder.

[dklawson]

You've obviously replaced a lot of parts but I didn't see that you'd replaced the points or condenser. Have you replaced them also? Have you cleaned and re-gapped the points? You report that the spark is weak. How did you check this? What about the spark looks weak?

[Big Man]

Mine was running like a complete dog, no power missing etc... posted a help question and turned out to be the points needed setting so all sorted and running great (apart from its black eye)

Cheers

BM

[itscomealongway]

You've obviously replaced a lot of parts but I didn't see that you'd replaced the points or condenser. Have you replaced them also? Have you cleaned and re-gapped the points? You report that the spark is weak. How did you check this? What about the spark looks weak?

as i am still learning i manged to get a hold of my friend who is a mecahnic and he re-gapped the points and said the condensor was fine, as for the spark he took the plugs out and tested them, i do not know exactly what he did as i am new to this and learning as i go along. i tend to get over excited at whats going on and then ask how its done after the event, but i guess i'll learn.

[dklawson]

It's very easy for the points to wear to the point that they make the car hard (or impossible) to start. If the old points were set without dressing them flat (or checking them with a dwell meter) the results are probably not accurate.

A condenser can't be judged by appearance. One that's failing can cause a weak spark. Weak sparks are often described as "orange". You can check the spark by resting a removed spark plug on the cylinder head (or other grounding point) which you watch while someone cranks the engine.

Before leaving the subject, how long has your car had this problem? Did you do any work to the car recently that this has suddenly happened?

[itscomealongway]

It's very easy for the points to wear to the point that they make the car hard (or impossible) to start. If the old points were set without dressing them flat (or checking them with a dwell meter) the results are probably not accurate.

A condenser can't be judged by appearance. One that's failing can cause a weak spark. Weak sparks are often described as "orange". You can check the spark by resting a removed spark plug on the cylinder head (or other grounding point) which you watch while someone cranks the engine.

Before leaving the subject, how long has your car had this problem? Did you do any work to the car recently that this has suddenly happened?

Thanks for that i will check the spark this evening if the rain stops and put a new condensor on, would one for a 1098 minor work ok? as for the problem, i bought the car i london a fortnight ago and drove it home to just outside glasgow,the problem developed part of the journey home after stopping at services and has continued from there!

[dklawson]

Almost any condenser from any similar Lucas distributor will be OK.

Examine the spark before you replace any components. Know what condition you're starting with.

While you have the dizzy cap off (in anticipation of replacing the condenser), put the car in gear and roll the car until the heel (cam follower) on the moving arm of the points is on the high point of one of the square cam lobes inside the distributor. Double-check your friend's work. Make sure there is a gap close to 0.016" between the points when the heel is on the high point of one of the cam lobes.

I've posted the following link a lot recently. Since this is new to you, take a look at the following web page and be sure to follow the links at the bottom of the page. They will walk you through how the basic ignition system works. It's a lot easier to troubleshoot problems if you've got an understanding of what's supposed to be happening.
http://www.howstuffw...tion-system.htm

[itscomealongway]

Almost any condenser from any similar Lucas distributor will be OK.

Examine the spark before you replace any components. Know what condition you're starting with.

While you have the dizzy cap off (in anticipation of replacing the condenser), put the car in gear and roll the car until the heel (cam follower) on the moving arm of the points is on the high point of one of the square cam lobes inside the distributor. Double-check your friend's work. Make sure there is a gap close to 0.016" between the points when the heel is on the high point of one of the cam lobes.

I've posted the following link a lot recently. Since this is new to you, take a look at the following web page and be sure to follow the links at the bottom of the page. They will walk you through how the basic ignition system works. It's a lot easier to troubleshoot problems if you've got an understanding of what's supposed to be happening.
http://www.howstuffw...tion-system.htm

thanks for your help.