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Help please no spark at plugs or points ??

Posted: Sat Nov 10, 2012 3:44 pm
by nige71
Hi All

Ok today i had land rover running lovely (v8 with pionts) so turned off to refit air filter while refitting air filter i
hit out ht lead from coil and low tension wire from coil.

When i put them back on i put low tension wire on + by mistake and now just wont even fire no spark at plugs
or points.low tension wire is back on -

I replaced coil and condenser with new ones but still nothing any sugestions please

Posted: Sat Nov 10, 2012 4:21 pm
by DEVONMAN
Check that you still have 12v at the +ve coil terminal.
You may have blown a wire/connection to the ign switch.

Posted: Sat Nov 10, 2012 4:23 pm
by DaveEFI
I'd guess you've burnt out the braid inside the dizzy. That's the extra flexible wire which goes from the points base which swivels to the fixed plate.

Posted: Sat Nov 10, 2012 4:35 pm
by nige71
all wires inside dizzy look ok is there any way to test.Thanks

Posted: Sat Nov 10, 2012 5:17 pm
by DaveEFI
A DVM. You can get them on Ebay etc for a couple of quid upwards. Essential for any electrical work. Easiest way to check the continuity of a cable.

Posted: Sat Nov 10, 2012 6:21 pm
by DEVONMAN
You can check if the dizzy connection is ok as follows.

Get a 12v bulb ( eg. side light . brake light etc)

Connect 12v to one side of the bulb.
Connect the other side of the bulb to the -ve dizzy wire.
Turn engine until you see that the points are closed.
The light should go on.
Now flick the points open and the light will go out.

If the bulb does not light up then the fault is in the dizzy connection, either the points or the braided wire.

regards Denis

Posted: Sat Nov 10, 2012 9:42 pm
by mgbv8
As Denis say's!!

If you accidentally connected the LT lead to the + side of the coil and turned the ign on you have probably blown the fuse for that circuit.

I would be surprised if the braided wire in the dissy melted to open circuit condition before the fuse blew.

Turn the ign on and check for 12 volts from coil + to earth. If you dont have 12 volts here you need to follow the wire back to its power source / fuse.

If you do have 12 volts here then you need to go the other way and check the 12 volt circuit from this connection through the dissy / points to earth to find the fault.

Posted: Sat Nov 10, 2012 10:32 pm
by nige71
ok 12v to coil ok and just tryed coil ht lead to coil and low tension wire both grounded and coil is sending spark from ht lead so surely got to be something in dizzy ?

Thinking along the lines that low tension wire no good which i will have to
oreder as harder to get have found supplier

or the braided wire on base plate us.

Posted: Sat Nov 10, 2012 11:32 pm
by DaveEFI
mgbv8 wrote:As Denis say's!!

If you accidentally connected the LT lead to the + side of the coil and turned the ign on you have probably blown the fuse for that circuit.

I would be surprised if the braided wire in the dissy melted to open circuit condition before the fuse blew.

Turn the ign on and check for 12 volts from coil + to earth. If you dont have 12 volts here you need to follow the wire back to its power source / fuse.

If you do have 12 volts here then you need to go the other way and check the 12 volt circuit from this connection through the dissy / points to earth to find the fault.
Which vehicles with Lucas electrics have a fuse fitted to the ignition circuit?

Posted: Sun Nov 11, 2012 8:19 am
by paul c
nige71 wrote:ok 12v to coil ok and just tryed coil ht lead to coil and low tension wire both grounded and coil is sending spark from ht lead so surely got to be something in dizzy ?

Thinking along the lines that low tension wire no good which i will have to
oreder as harder to get have found supplier

or the braided wire on base plate us.
If you have spark there then the LT side is okay, it is in the HT side, look at the rotor and cap.

Posted: Sun Nov 11, 2012 7:36 pm
by nige71
Hello All

Ok got it running today checked everything with fluke multimeter
and every thing was as should be so cleaned the points and she fired up

the metal on the points is black and purple wondering if cooked !

when running starts missing and backfiring before cutting out and then is had to start.

was running perfect before my little accident with lt wire
going to get set points monday fingers crossed that problem.

any one have any info best way to set points up.

Thanks Nige

Posted: Sun Nov 11, 2012 8:10 pm
by Ian Anderson
Burnt out condenser?

Posted: Sun Nov 11, 2012 9:25 pm
by nige71
as my first post says i put new coil and condenser unless its faulty .

Posted: Sun Nov 11, 2012 10:44 pm
by DaveEFI
It sounds like you've put 12v at high current across the points so they are likely to be burned. If not too bad they can be filed down (each contact should be a dome) or simply replace them. The initial gap is 15 thou - but they are best set with a dwell meter. There is an adjuster on the outside of the dizzy to make this easy. After setting, check the timing with a strobe light. Once both of these are correct, re-setting the dwell once in a while will also bring the timing back to the correct point.

Posted: Mon Nov 12, 2012 6:36 am
by Ian Anderson
nige71 wrote:as my first post says i put new coil and condenser unless its faulty .
Damn -missed that!

Was the new one covered in a waxy coating? Did you clean it of the electrical contact parts?

Ian