Practically Classics Forum

Hi I have a 1974 2200 P6 SC, bog standard but it won't fire. It was going perfectly till the cowboy sprayer I gave it to left it out in a force nine gale, the car got wet but it had it's bonnet on. It won't start now. I've checked for fresh petrol, cleaned the pump etc. Cleaned the sparks and checked the cap, points etc. I took off the Ht lead from the distributor from the coil and when I turned it over I didn't see any sparks. I had already done this with a spark plug lead with the same result.

I suspect the coil is duff, there is power going to it and i cleaned the spade connections. Ive now ordered a new coil on ebay, but there's a blue capacitor/resistor wired to the coil connection. Is this the ballast resistor and if so could this be causing the non-starting? It's not even kicking, just turning over. Ideas?

Have you got a multi-meter? If so set it to volts, turn on the ignition and put it between the positive terminal of the coil and earth. If you don't see any voltage (12 or 6 depending if you have a ballast resistor or not) then it is possibly the ballast resistor that has died. If you do then the coil itself is suspect.
With no voltage and as you know where the ballast resistor is measure the voltage between the input side of it and earth. If you have power there but not at the coil it is definitely the resistor, if there is no power at the input then check the fuses then the ignition switch plus every connector in between.
If you don't have a meter you can use a bulb and a couple of bits of wire to check to see if there is power. run the bulb directly from the battery to test it and so you see how bright it is when 12v is applied so you can tell if you are getting 12, 6 or less when you test different circuits.

The blue thing is most likely a radio supressor, post up a photo please so we can tell you for sure.

The 2200 has a ballast resistor, the resistor actually being a resistive length of wire running from the ignition switch to the coil. With the ignition switch on you should see around 7 volts at the coil if the points are closed, 12 with them open. The ignition circuit is not fused. You should see a second connection to the + terminal of the coil, this runs to the starter motor and its purpose is to supply 12 volts to the coil via an auxiliary contact in the solenoid when the engine is being cranked, the ballasted supply being cut off when the switch is in the start position. Check that this is present and working properly. I had exactly the same problem with my car, the spade terminal had broken off and some bodger had crudely soldered the connection on and this had subsequently failed. A quick check is to see whether the ignition and oil lights go out, as opposed to just dimming, during cranking, if they do then that's your problem.

My 4 pot P6 is particularly susceptible to damp on the ignition system causing poor spark performance. Give all the HT leads, coil and dissy cap a good spray with something like GT85 and try again.

Dave

Thanks for all the above guys. I will check the voltage readings with my multimeter the next time I'm out at the car (its at my parents place about 10 miles away). I don't suppose it's any harm to have a good spare coil if it turns out my one is ok. I thought myself the blue thing was more like a suppressor than the ballast resistor. I'll update you as I work through everything. It's probably good that I can't start it at the moment, I had to get the radiator repaired after I took a lump out of it with the angle grinder

Well I've tested the voltage. I had six volts at the coil so the ballast resistor is working anyhow and I have power. On the positive connection I have two wires going into one spade connector. It looks factory fitted and not a bodge so I presume one is the 12v feed from the starter and the other is the normal ballasted feed from the ignition.

I'll wait till I get the new coil and see if i can start the obstinate devil.

6 volts at the coil would be normal for when it's running, but there should be 12 volts when cranking - what's the reading at the coil while cranking?

It's quite possible that it will be zero, because this is switched to a different circuit by the ignition switch, and therefore this could be your problem.

Cheers

What he said. The second wire is indeed the feed from the starter and the power through the ballast is cut off by the ignition switch when cranking.

Ah, well I didn't check during cranking, A: I was on my own, B: never thought of it .... oh and C: My battery is a tad duff, even when fully charged. I'll need a booster pack when I go to cranking it. However thanks for the clarification, I will check the voltage before I change the coil when I'm turning it over.

The coil came in the post today , only issue is it came with screw connectors and mine are spade/blade connections, easy bodge though just put blade/spade on one end and a circular end on the other. I'm not cutting wires.