7 replies to this topic

[MattyD783]

Pulling my hair out now.

I've trawled forums and topics,  read and re-read the Haynes manual etc etc, and yet I now find myself starting yet another 'starting issue' :-(

 

998cc Mini

No spark from coil

Tried lead off of dizzy, held to block..nothing.

Changed condenser (tried 3 now)..nothing

Changed all usual others - cap, rotor, ht lead, points.

Points gapped correct

Tried another coil...still nothing

Checked power to coil...all good

Checked and double checked inside dizzy for earthing issues...nothing stands out..even taken back plate off to check...found a stray washer lurking!.....still nothing.

Checked little earth wire in dizzy too and thats fine....

 

whats left??

Only thing I can think of is unlucky with getting several dud (cheap) condensors, spare coil was also fried, or both ht leads i've tried were shot.... all of them seem unlikely.

 

Please help :-(

 

Matt

 

Sorry also should mention about the lead up to this issue.  Car was losing power after warming up.  This happened on several occasions, on the last couple I think it was accompanied by a few pops and bangs and now i can't get her going.  Thought it was going to be straight forward condenser.

Edited by MattyD783, 24 May 2013 - 09:45 PM.

[lrostoke]

a quick test of the coil would be plug a HT lead direct into the coil, hold sparkplug onto block.

 

disconnect negative connection on coil and attach a spare bit of wire....keep tapping wire against a good earth such as head bolt. simulates points opening

see if you get a spark at the plug

ignition on obviously

 

if you get a spark then problems at the dizzy end. Or maybe even a break in the wire from the coil to dizzy

[Captain Mainwaring]

a quick test of the coil would be plug a HT lead direct into the coil, hold sparkplug onto block.

 

disconnect negative connection on coil and attach a spare bit of wire....keep tapping wire against a good earth such as head bolt. simulates points opening

see if you get a spark at the plug

ignition on obviously

 

if you get a spark then problems at the dizzy end. Or maybe even a break in the wire from the coil to dizzy

Well you might. You've taken the condenser out of circuit.

[Captain Mainwaring]

Pulling my hair out now.

I've trawled forums and topics,  read and re-read the Haynes manual etc etc, and yet I now find myself starting yet another 'starting issue' :-(

 

998cc Mini

No spark from coil

Tried lead off of dizzy, held to block..nothing.

Changed condenser (tried 3 now)..nothing

Changed all usual others - cap, rotor, ht lead, points.

Points gapped correct

Tried another coil...still nothing

Checked power to coil...all good

Checked and double checked inside dizzy for earthing issues...nothing stands out..even taken back plate off to check...found a stray washer lurking!.....still nothing.

Checked little earth wire in dizzy too and thats fine....

 

whats left??

Only thing I can think of is unlucky with getting several dud (cheap) condensors, spare coil was also fried, or both ht leads i've tried were shot.... all of them seem unlikely.

 

Please help :-(

 

Matt

 

Sorry also should mention about the lead up to this issue.  Car was losing power after warming up.  This happened on several occasions, on the last couple I think it was accompanied by a few pops and bangs and now i can't get her going.  Thought it was going to be straight forward condenser.

 

 

Sounds like coil to me, they can go twanky as they warm up.

However, go back to fault finding basics.

Electrics off, distributor cap off, car in top gear, coil -ve off, bump the car and test with a multimeter from points fly lead to ground and make sure you get a loop when they are shut, and open circuit when opened.

Let's say you do, even if the gap is wrong you should get enough spark to run....check the condenser - you can charge it up using a multimeter on resistance range - the condenser will take a charge then the apparent resistance will rise., quickly take the leads off and switch to DC volts, and should should see the charge in the capacitor (You need to do this with everything disconnected).

 

Assuming the above two are ok, move on to the coil - actually a bit difficult to test at home, but you can try what the other poster suggested above, you really a capacitor between coil -ve and ground when you do your spark test though.

Favorites that spring to mind are the points assembled up wrong and continuously grounding and also points that have been cleaned with abrasive paper having a grain of abrasive stuck between the points tips.

 

Thee isn't really too much to go wrong with a points setup. Just fault find logically.

Edited by Captain Mainwaring, 24 May 2013 - 11:16 PM.

[MattyD783]

Just before I head to the workshop to try these and other ideas out.. Of the two coils I've tried, the original one I was using at the time of breakdown gets very warm when cranking the engine, and the other one I've tried (intermotor!) Which was in a box of spares I had, remains completely cold...oh and I also noticed the blue plastic has melted in my nice new points..
I have some other old coils lying around which I think I'll try, as I don't think I'll be able to get another till after bank hol now :-(

Edited by MattyD783, 26 May 2013 - 07:43 AM.

[lrostoke]

coil shouldn't get hot that quick, so something not right there.

 

and plastic melting on the points isn't a good sign.

[Captain Mainwaring]

Why guess? Do you have a multimeter? You've been given a systematic way to go through the problem and despite probably welding the points up, you want to carry on substituting parts of dubious origin.

With respect, you're pulling your hair out because your trying to clear a fault without using logic.

[MattyD783]

Why guess? Do you have a multimeter? You've been given a systematic way to go through the problem and despite probably welding the points up, you want to carry on substituting parts of dubious origin.
With respect, you're pulling your hair out because your trying to clear a fault without using logic.

Also with the utmost respect,I was simply adding some more info into what I had found initially when trying to diagnose the fault. I do have a multimeter, and although it is not my strongest point of knowledge, I did manage to work out a few things like there was power to the coil etc. I just wondered what peoples thoughts were on the coil heat before I go to the workshop and commence with the gratefully received advice. I wasn't about to head straight out and buy a new coil first
I'll let you know how it goes.
Thanks
Matt