14 replies to this topic

[minirock]

Make; Austin
Modle; 1987 mayfair 998cc
hs4 carb cone air filter

Right,



12 months ago the car has done less that 10 miles and it had brand new coil plugs leads cap points and condensor

dont really know where to start, my mini was running fine one day turned it off and the next day it was really difficult to start and when it did eventually start it was running really rough, cleaned out the fuel tank, lines cleaned the carb put lots of petrol in replaced the points and condensor and it ran but badly, it now has a really poor spark and is misfiring and im puzzled

everything is set properly

Can anyone help me PLEASE? your my last hope

Thanks in advance
James

[lorry]

Did you set the gap on the points?

[bmcecosse]

Could be many things - from blown head gasket/burned valve, to lack of oil in the carb. Can you get a compression check done to check general engine condition ?

[minirock]

Did you set the gap on the points?

yeh to 0.4mm

there is fuel getting to the carb aswell because i took the pipe going to the float bowl and cranked the engine and petrol flew out

Cheers

[minirock]

Could be many things - from blown head gasket/burned valve, to lack of oil in the carb. Can you get a compression check done to check general engine condition ?

compression test done and its 170psi across all 4 cylinders and i have ATF in my dashpot

Cheers

[bmcecosse]

Oooh - well that's good compression! So - must be down to ignition - can only suggest process of elimination - but suspect the condenser/rotor arm/dizzy cap in that order. Any chance you can fit another dizzy complete ? Connections at the coil are worth checking - many will say 'get a new coil' - but in my experience it's very rarely the coil - but if you can try another........... Should be a 9 volt coil to go with the ballast ignition. If you have a 12 volt coil - running on 9 volts - that could explain the poor sparks.

[lorry]

Do you have a spare coil to try, how's the engine earth cable and all the electronic connections?

[minirock]

i dont have another dizzy no

where should there be 12v on my coil?

and all the conectors are good

Cheers

[bmcecosse]

9 volts or so at the coil terminals!

[minirock]

if there is 9 volt or so at the coil

then what?

thanks for your help

[dklawson]

If you want to determine what coil you have and which you need, you will need a multimeter.

Mark and remove the low tension wires on the coil. Set the meter to Ohms and measure across the coil terminals. If you find around 3 Ohms, that's a standard 12V coil. If you measure between 1-2 Ohms, that's a ballast ignition coil.

Put the wires back on, remove the dizzy cap, and put a coin between the points. Set your multimeter to Volts and turn on the ignition. Measure the voltage between the coil (+) terminal and an earthing spot. The coil (+) terminal is the low tension terminal that is NOT connected to the distributor... it comes from the ignition switch. If you measure 6-9 Volts between coil (+) and earth, you have a ballast ignition system. If you measure 12 V, you have a standard ignition system. Turn off the ignition and remove the coin.

You need to use the right type of coil for your ignition system. If you use a ballast coil with a standard ignition system it will pass too much current and your point, condenser, and coil will have reduced life. If you use a standard coil on a ballast ignition system, not enough current can flow and the spark will be weak.

[minirock]

right, ivechanged my coil to a ballast one (what it sould have)

and the spark is good, when it actually sparks . . .

sometimes it will spark, other times it wont

cheers

[majj2]

right, ivechanged my coil to a ballast one (what it sould have)

and the spark is good, when it actually sparks . . .

sometimes it will spark, other times it wont

cheers

Have you tried changing the HT leads as i had a similar problem and a new set sorted it.
And is the dizzy cap in good condition??

[delboyeire]

im nearly finished rebuilding my mini and when i first got the engine in i had this exact same problem, so i went through a long elimination process, started with ht testers on the spark plug wires and then also on the coil to dizzy wire and realized the spark from coil was weak so i replaced the coil with one out of a capri,still wouldnt start,then changed points and condenser to ones out of a spare mini engine i had,still no go,i then took the whole dizzy assembly out of the spare and she tried to start but just wouldnt give a good kick,then changed points condenser and rotor arm,done static ignition timing(very tedious) realised spark plugs wernt connected right when doing the timing,so considering i used the ignition timing to plug in the spark plugs correctly(or incorrectly as the case was before)it meant that the plugs wernt connected right and this caused the plug cable to pull on the distributor cap which meant the it wasnt sitting right which in turn damaged the rotor arm which meant the ignition timing was all over the shop,jesus thats a long story sorry got carries away lol

[GuamMini]

I am in the same boat as the OP of this post. My car would start and then stall and then die at idle. If I richen the mixture it would rev but would not idle for a few seconds and it made the spark plugs black. I set the carb to its initial setting and set the static timing, valve timing, points gap. it would start but would not rev. I richen the mixture one flat at a time and it would rev but still stall at idle. i remove the plugs and the mixture is too rich.

 

I thought it was the cap, rotor and wires and replaced those and even bought a new dizzy and still the same. Any idea?