Ignition coil has to be grounded?

[oldelanman]

Phil,
Could be your ignition switch causing the voltage drop ... corrosion of the contacts leading to high resistance. This was my original switch and the Ign/Run and Start contacts were the worst affected.

[ericbushby]

Hi Phil,
11.75 volts sounds good to me.
It is possible to measure the volt drop at each connection in the circuit and also end to end on each wire, and they should all add up to 11.75v.
I realise though, this is an over simplification and due to access difficulties it is often impractical.
The principal remains the same though, that voltage loss is somewhere and you should be able to find it.
Try large sections of the wiring at first until you have it surrounded and then close in.
Reading this forum the most common problem seems to be earth connections.
Sorry, I cannot be more helpful.
Keep going, you will get there.
Eric in Burnley

[pharriso]

Keep your voltmeter probes between the coil +ve (or -ve if it's a +ve earth vehicle) terminal and ground (check of course that the coil has been wired the correct way around according to battery polarity - i.e +ve or -ve ground)

Reading is around 9V with ignition key in the start position and cranking - check.
But what is the reading directly at the coil with the ignition key in the run position??

Yep 8.6-9.2v Cranking
Ignition on, engine not running 12.7v
Ignition on, engine running 13.8v

No Ballast wire in the circuit if that's what you were looking for....

[pharriso]

Hi Phil,
11.75 volts sounds good to me.
It is possible to measure the volt drop at each connection in the circuit and also end to end on each wire, and they should all add up to 11.75v.
I realise though, this is an over simplification and due to access difficulties it is often impractical.
The principal remains the same though, that voltage loss is somewhere and you should be able to find it.
Try large sections of the wiring at first until you have it surrounded and then close in.
Reading this forum the most common problem seems to be earth connections.
Sorry, I cannot be more helpful.
Keep going, you will get there.
Eric in Burnley

It was actually 11.45, but the principle is the same...between the battery & the coil I am loosing 11.45 - 8.6 (to 9.2v), say 2.5v.

Between the starter soleniod & the coil connection I am loosing 9.9 - 9.2 (to 8.6v) in a circuit that is only powering the ignition & starter solenoid (5 amps?) 1v - so I think I need to concentrate here.

Phil,
Could be your ignition switch causing the voltage drop ... corrosion of the contacts leading to high resistance. This was my original switch and the Ign/Run and Start contacts were the worst affected.

My Ignition switch is actually only 2 months old, but I think the issue is with the wiring near the switch... it has to be...

[2cams70]

Yep 8.6-9.2v Cranking
Ignition on, engine not running 12.7v
Ignition on, engine running 13.8v

Yes obviously a non-ballasted system.

Can you try measuring voltage at the battery again during cranking? - only this time with the coil connected. I know you measured around 11.4V previously with the coil disconnected but try doing it again under exactly the same conditions under which you got 8.6 - 9.2V at the coil.

8.6-9.2V does sound a bit marginal particularly if the battery is in good condition and the weather isn't very cold.

[2cams70]

You need to be sure too that that loose wire near the coil is not supposed to be a system ground for other unidentified circuits (maybe it's not a coil ground at all!!). If it's floating around in thin air it won't be doing it's job!

[mbell]

Where are you powering the electronic ignition from?

The modules have a minimal voltage which they work at. I've had trouble with mine not starting after a lay up that I think is due to a build of of voltage drops in supply and ground circuits, taking the supply voltage too low for the module. If I hook a jump start up to the solenoid and engine it fires easily.

I'd make sure it isn't powered from the coil and possibly test by hooking it up to a separate 12v power source, e.g. a different battery.

[pharriso]

Where are you powering the electronic ignition from?

The modules have a minimal voltage which they work at. I've had trouble with mine not starting after a lay up that I think is due to a build of of voltage drops in supply and ground circuits, taking the supply voltage too low for the module. If I hook a jump start up to the solenoid and engine it fires easily.

I'd make sure it isn't powered from the coil and possibly test by hooking it up to a separate 12v power source, e.g. a different battery.

Mark, sounds like you have/had the same issue as me. My Electronic Ignition unit is powered from the coil.... but whether the 8.6-9.2v is insufficient for the Coil, or if it's insufficient for the module doesn't matter, the voltage drop needs reducing.

Update: Just found the spec sheet for my module (attached), says operates 6-18v, so it's the coil that provides insufficient spark at 8.6-9.2v.

CraneCams_ZR700_Points2ElectronicIgnitionModule_404-405.pdf

(110.12 KiB) Downloaded 279 times

For now the Ballast Bypass lead from the solenoid is working nicely...

[mbell]

Mark, sounds like you have/had the same issue as me.

Quite possibly. I am running a pertronix ignitor I and pertronix coil. The car was originally wired for a ballast setup but its current running normal 12v system. My module is powered separately to the coil via a relay with power coming directly from the solenoid battery connection. I suspect it is seeing various voltage drops in the system when cranking, both on the 12v supply and ground connections.

I've had some success in improving it by another attempt at cleaning/improving the engine and battery earth connections.

Last two times I started it, once it fired straight up, second time took a lot of cranking but it did fire with out the booster pack (battery had been on trickle charger). If I do continue to have issues I have recently got a bluetooth scope thing that should allow me to monitor voltage drops across connection when cranking and see if i can find a specific issue.