discool

Well-Known Member

• Dec 4, 2014

• #1

My disco engine lost the will to live last Sunday with no spark from the coil and I’m now spending part of the evenings under the bonnet but without any luck.

So not doing what I preach (test first) I went and purchased and fitted a new amplifer only to find things are still the same.
So on to testing, the coil voltages in and out as according to Rave, so with all wires on the coil in place and with my meter leads in placed between battery neg I’m getting the batteries voltage at the + and - on the coil with the ignition switched on, so okay there.

Now still with all wires in place and with my meter leads in placed between battery poss and with the ignition either on and off and at both coil terminals I’m getting a battery voltage, but according to Rave the meter should be showing zero volts.
After removing the all the wires from the coil I find the earth connections to give this reading is on both the wires from the amplifier (white and white/black), which is identical even with the new amp in place.

I’m even testing resistances as follows.
Coil primary is 0.9 ohm …Ok
Coil secondary is 6.94Kohm ??
Dizzy pick-up module 4.842Kohm… Ok
And I thought, just wiggle of a wire and I’m away.
I don’t know now if I’m missing anything so any help is appreciated.

 

Last edited: Dec 4, 2014

cooltide

sheep fancier

• Dec 4, 2014

• #2

With ign on, have you checked voltage from amp screw to ground ?

 

discool

Well-Known Member

• Dec 4, 2014

• #3

cooltide said:

With ign on, have you checked voltage from amp screw to ground ?

Click to expand...

Hi mate, yes exactly as shown in Rave and it's zero.

Found out tonight that with every thing put back together as it should and ready to go, although no spark, if that when turning off the ignition there is a short buzz sound coming from the dizzy, the only thing to do that must be the pick-up

As pick-ups are very reliable' so Ive read, hopefully it's this no spark problem that is causing the buzz.

I see a Bosch-coil for the 3.9 can be around £50 so expensive to find out the original coil is ok.

 

cooltide

sheep fancier

• Dec 4, 2014

• #4

Bought one off rstlandrovers eBay nearly 6months ago. I know as I got Bosch leads from powersparks at same time. Can't access item tho, too old. They have one listed for £10 odd titled Bosch. Check it is as the description says Lucas. I do remember it being a bargain and it was genuine bosch. Worth having as spare.
Has the old one leaked?

 

cooltide

sheep fancier

• Dec 4, 2014

• #5

Had bother with the black red capped cheapo "12v electronic coil" in the past.
I'd swap ht lead too. But I do tend to swap bits till it works when baffled!

 

Last edited: Dec 4, 2014

discool

Well-Known Member

• Dec 5, 2014

• #6

Well she's up running smoothly, but only with a 12v supply to the coil +ve terminal from the batteries +ve although the 12v supply from the 'spider' is still at the coil +ve when the engine is mobilised.

So now the question is what's wrong with the 12v supply from the spider to the coil, as its there all the time when mobilised even under cranking.

Still have a short buzz from dizzy when the ignition is turned off, something I've never done I with the bonnet up is turn on and off the ignition, with the bonnet down u can't hear any buzzing.

 

discool

Well-Known Member

• Dec 5, 2014

• #7

Further to the above, I'm removing the spider connection to the coil and installing a fresh supply to the coil +ve from the ignition switch, job done.
I'm not delving into the bowels of the "spider" to find what's wrong with the feed from it to the coil, although the D1 has a IGN controlled terminal on if fuse box which at present I have my mobile car kit connected, so I will be trying using that option.

 

discool

Well-Known Member

• Dec 8, 2014

• #8

All done and dusted and back to normal with a link wire in place from the IGN switch to the coil, so much for immobilisers although the starter circuit is still inhibited by the spider until it receives the signal from the key fob.

I have notice that the engine turns over better on starting and then runs much smoother, so this iffy spider has had its issues for some time maybe.

And the good part in rectifying my issue was I don't have to get access to the spider, shame I rushed out and spent £27 on an ignition amp that I didn't require.

 

Last edited: Dec 8, 2014