Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Help again please - 1993 +8 ?ignition

Chaps,

My nightmarish sprint season continues, with multiple breakdowns. The problem appears to be ignition electrics.

Background - after 3 years use without problems, the car stopped and refused to start. With no diagnostic kit with me, we had the car transported back home from the meeting. I initially thought there was an injection issue, as the car started once I had used the "clear fault codes" feature of RoverGauge. Nevertheless, I changed the fuel pump and injector relays.

The car subsequently ran perfectly for about 150 miles. It then stopped, and would not restart.....transported home again. There was definitely no spark, and when I inspected the coil (Bosch OEM, probably original), under the cover was an unpleasant underseal-like material seeping from the top. I replaced the coil like-for-like, the car restarted instantly, and ran for a further 100 miles without fault. My only observation was that the coil seemed rather hot after running, but I don't know what "normal" is. Yesterday I drove without issue to the next sprint meeting, and the car then would not start in the paddock. After much grinding away on the starter, the car did suddenly burst into life, so I scratched from the meeting and drove home (without any issues). On all occasions that the car has stopped, I could hear the fuel rail pressurising as I attempted to start it, so I don't think that fueling is an issue.

The previous owner had fitted a Mallory Unilite distributor, and dispensed with the ignition amplifier. This is how the car was when I purchased it from a Morgan dealer. I now suspect that the installation may not be correct. The coil connections are as follows: Positive terminal: red wire from the distributor, (a rather faded) yellow with a black tracer wire from the wiring loom, and a condenser. Negative terminal: green wire from the distributor, white with a black tracer wire from the loom. There is no ballast resistor fitted near the coil.

So, to the questions for the cognoscenti:

Does the +8 of the 1993 era (Lucas 14 CUX) have a ballast resistor (or loom resistance wire) somewhere in the wiring loom? If so, where is it? (I've looked in the obvious places, but it IS a Morgan, after all). Is there any way I can easily check whether a ballast resistor has been fitted out of sight (voltage in one of the coil wires?).

Do any of you have a Mallory Unilite distributor fitted, and if so, please could you let me know how yours is wired?

My best theory at present is that there isn't a ballast resistor fitted, and there should be, as per the Mallory installation instructions. This is slowly cooking the coil, and - again, as per the warnings from Mallory - is in the process of destroying the ignition module.

Apologies for the lengthy post - but if I can't sort this, the car will be moved on; I don't do unreliability in a vehicle. It was already on a Final Written Warning before yesterday's debacle.

As usual, thanks in advance for your replies and thoughts here.

Dave

A Ballast resistor will drop the voltage to the coil to between 6-9V. Just check the +ve feed to the coil.

Have you got a 'model number' for the coil? That should tell you if it's ballasted coil or not.

Thanks, TBM - is it just a case of disconnecting the feed wire, turning the ignition on and measuring the voltage from that to an earth point?

The coil is the standard Bosch one for TCI ignition - Part no 0 221 122 392

Dave

Yes - correct. When you turn the starter it should jump to 12V.

However, as the distributor takes its 12V feed from the coil, I'm going to assume that it's a 12V non ballast system. (I have a ballast resistor, and the feed for my ignition module is taken from the 12V side of the ballast resistor, not the 9V)

TBM - apologies - my electrical knowledge is limited. If there is a ballast resistor in the system, then should the feed wire to the coil always have the reduced voltage?

The reason for asking about whether a +8 loom contains a ballast resistor/loom resistance wiring is that, according to the Mallory installation instructions, my car is wired assuming that fitment. If there is not a ballast resistor/resistance wiring already present, then my car is definitely wired incorrectly. Hopefully someone can give us the definitive answer....but in the meantime, I'll check the feed wire voltage piece.

Checking that coil reference, it comes out as 14 volts, so not a 9 volt coil for a ballasted system, see https://www.autodoc.co.uk/bosch/676491

I suppose that if you have a ballast resistor in the wiring, the feed to the coil will only be 9 volts once the starter motor is no longer turning. What voltage do you have at the coil with the ignition on but the starter motor not turning? It should be 12 volts.

Tony

On a traditional ballast system, there is a piggy back wire to the starter solenoid so that for normal running, there is a reduced 6-9v supply to the coil, but when starting, that jumps to 12V to give it a boost. As soon as the starter is disengaged, the voltage drops.

I've been reading about the Mallory and as you mention, it does say you should have a ballast resistor in place.

More reading (I'm very bored during my enforced isolation)

It seems your symptoms (hot coil) are very common when running without a ballast resistor, and as you're taking the live feed for the Dizzy from the coil I'm pretty sure you don't have one. There is a possibility that you've unintentionally fried the Unilite.

Solutions?

Fit a ballast resistor and ballast resistor coil (needs to be the right ohm rating) - fairly cheap to do (under £50). There may be an issue with starting due to voltage drop, but unlikely at the dizzy is electronic and has 12V power. This will also be dependant on the Unilite being OK.

Fit an alternative Distributor that doesn't require a voltage drop.

Quick update - the voltage at the disconnected feed wire with the ignition on is 12.4v. Oh dear.....

At least now you know the source of all the problems. First step to recovery.