No spark?! Resolved - Culprit Found!

[300CE]

Well the old girl has gone from running sweet as a nut to not starting today. She'll turn over strongly but there's not even the slightest hint of a spark. I've checked all the leads and connections & even swapped over coil, however, whilst cleaning up the dizzy and checking the rotor, I spotted this on the dizzy cap - it looks as though the rotor arm has been hitting the plastic as you can see where it's broken bits off:



Van hasn't been started since last week, but can't see how it can be ok one minute and then nothing. It's not even like it's been really cold!

[itchyfeet]

have you checked for 12v on the coil plus to ground

[300CE]

Haven't checked that Paul as multimeter is at my pals garage - will get this checked asap

[what2do]

Well the old girl has gone from running sweet as a nut to not starting today. She'll turn over strongly but there's not even the slightest hint of a spark. I've checked all the leads and connections & even swapped over coil, however, whilst cleaning up the dizzy and checking the rotor, I spotted this on the dizzy cap - it looks as though the rotor arm has been hitting the plastic as you can see where it's broken bits off:



Van hasn't been started since last week, but can't see how it can be ok one minute and then nothing. It's not even like it's been really cold!

I changed mine about 3 weeks and noticed that the old one was exactly like yours. I wondered if it was a manufacturing flaw. Go have a look at your brand new one cap and see if that reveals anything. Ps. Mine was changed as a matter of course not because of any electrical issues.

[itchyfeet]

Haven't checked that Paul as multimeter is at my pals garage - will get this checked asap

better than a multimeter connect a bulb
a multimeter drawns no power so may not show up a broken wire or ignition switch fault for example

[300CE]

Cheers chaps - could well be a flaw with the cap then Mitch - I've just ordered another rotor arm and dizzy cap (current ones weren't changed that long a go) and will check 12v as well - pretty sure I've got a bulb connector already made up. Was thinking that I might have flooded it a bit so am going to leave it for an hour then will try again.

Other thing I was thinking of was the HT leads - they're a few years old now and will have taken on some considerable heat over that time - they were from GSF so not sure as to how efficient they are.

Will report back

[300CE]

OK, took spark plugs out and 3 of them are wet with fuel so looks like I've flooded the old girl. Have dried off plugs, sprayed a little easy start down the carb but still not catching. I then checked the condition of the battery and the level indicator was black (should be green) - I've now put that on charge and will try again once it's fully charged and check voltage along with the coil.

Surely couldn't be as simple as a weak battery could it?

[itchyfeet]

Surely couldn't be as simple as a weak battery could it?

When cranking the voltage will drop, if you have a low battery it drops much more, this all weakens your spark because the coil is not storing so much energy.

[300CE]

Cheers Paul, I reckon this could possibly be the culprit - I know she doesn't like standing to long & I've only been using her at weekends recently since I started a new job. Think I'm deffo going to invest in one of those ctek chargers to keep it topped up. I did use to start it up through the week, but think this did more harm to the battery than good.

I'm going to change the dizzy cap anyway and picked up some Bosch Platinum single electrodes for a tenner as I have Bosch triple electrodes in there at the moment.

Once I've ruled out continuity on the coil, i'm sure she'll be up & running in no time.

[itchyfeet]

deffo need an intellegent/smart charger
I bought one of these, it's permanently connected to the batt so I just have to plug mains in and it's charging. Unlike some it auto detects what mode is needed so no buttons to press and much lower cost then a ctek

http://www.ebay.co.uk/itm/HILKA-12V-or- ... SwSHZWc~2S" onclick="window.open(this.href);return false;

[martin83]

The best way to test an ignition system is with something like this
http://m.ebay.co.uk/itm/Trident-Logic-P ... 1148503017" onclick="window.open(this.href);return false;

Check at positive side of coil for power. Then negative side of coil whilst cranking for a flashing negative.
If there is no blinking led on earth side of coil whilst cranking then points/hall sensor or ignition amplifier at fault.

If the coil checks OK remove the king lead from centre of dizzy cap and hold it (with plastic ht pliers) just away from distributor contact and crank. If you have a spark jumping in but not coming out then it is arcing out to earth inside the cap this usually means a faulty rotor arm, quite common with modern low quality parts.
Hope this helps.
P.s the chipped plastic on the inside of the cap is normal.

[300CE]

Paul/Martin - many thanks for all your help and input chaps and for the links, it's really helpful & much appreciated.

I'm gonna get one of those chargers put on my Xmas list & leave an extra mince pie out for Mr Claus.

I'll report back with an update!

[itchyfeet]

if you use an old fashionded charger then 12 hours is about enough or you can over charge it.

The smart charger allows you to leave it connected whenever you are not driving it, it will charge as it needs to.

[300CE]

OK, the plot thickens! Put the freshly charged battery on (indicator now green) and after about 10 seconds of cranking she started - marvellous, i thought! Choke all working on the carb as idle was between 1500/2000 rpm - she ticked over fine for about 2 minutes then just died - couldn't re-start for love nor money.

My thoughts are now directed to an iffy fuel pump/push rod - what do you folks think?!

Cheers in advance,

Justin

[itchyfeet]

less likely than ignition I'd think, test pump output by removing pipe to carb, point into jar and get a helper to crank, disconnect coil for safety.