9 replies to this topic

[copperhead51]

I'll start form the top hahahah

I am trying to get an old rally car back to life, there is no wiring harness (at least a useable one) in the car. So, I have new plugs, wires, cap seems good, and a new coil. But there is no spark.

I have my car battery hooked up providing power to the + side on the coil and the ground on the coil going to just the distributor, and the lead wire out of the coil going to the center hole on the cap. but then when i give power to the starter, the engine turns over and does not have any spark, the fuel is there cause im just using starting fluid to try to get it to kick over at least a little.

Soooooooo, i guess my question is.... Do i have something hooked up wrong? Why is there no spark?

Thanks!!!

[lrostoke]

Sounds like it should work.

postive off battery to positive on coil.
black wire from dizzy to negative on the coil.

good earth from battery to engine.

then positive off battery to solenoid. to engage starter



Before engaging starter, remove dizzy cap and flick the points make sure they are sparking, also make sure when you turn the engine they actually open and close and the gap is right.

[Pigeonto]

I'll start form the top hahahah

I am trying to get an old rally car back to life, there is no wiring harness (at least a useable one) in the car. So, I have new plugs, wires, cap seems good, and a new coil. But there is no spark.

I have my car battery hooked up providing power to the + side on the coil and the ground on the coil going to just the distributor, and the lead wire out of the coil going to the center hole on the cap. but then when i give power to the starter, the engine turns over and does not have any spark, the fuel is there cause im just using starting fluid to try to get it to kick over at least a little.

Soooooooo, i guess my question is.... Do i have something hooked up wrong? Why is there no spark?

Thanks!!!

Not trying to be funny but you didnt mention rotor arm is on or renewing the condenser.Sometimes new points have a protective coating on the faces which needs thinners or similar to remove it.Check that the insulator piece/s are on the points and theres no chance of them earthing out.

[dklawson]

As above, check the points and make sure they are clean AND gapped right. And do fit a new condenser at the same time. The wiring you describe should work as long as you have the earth post on the battery connected to the engine block (either directly or using the car's "standard" earth straps). One way or another the engine must be electrically connected to the earth terminal of the battery.

I don't believe you mentioned the age of the car or its engine so we don't know what distributor is in it. If this is an OLD engine with the DM2 or 25D series distributor, there are nylon washer/spacers that must be in the right place when the points are fitted. If these are omitted or installed in the wrong place then the ignition system will not work (no spark).

Work through the problem step by step. Start with a new cap, rotor, plug wires, points and condenser. If you need info on how to fit and adjust the points, post back here.
Once the new parts are on, perform a quick test of just the coil. To do this, wire it up as you have. However, take the lead out of the center of the dizzy cap and hold it near a metal spot on the block. This will eliminate the cap, rotor, and plug wires from the equation.
Use a screwdriver to open and close the points (with the ignition on) while you watch for a spark to jump from the coil high-tension lead to earth.

When opening the points with a screwdriver, use the screwdriver as a wedge to pry the insulated heel block off the 4-lobe cam on the dizzy shaft.

Remember that the spark only happens when the points change from closed to just open. The spark is not continuous and will not occur when the points are sitting closed or sitting open.

[copperhead51]

Thanks for all the help! I just got a new condensor and points for like $10 so i'll be installing those this afternoon. I'm hooking the engine up just as it is in that video, (except it is still in the car). So it seems as if everything is wired correctly, should i take the battery from my car and actually ground the battery to the old Mini? or ground it off the coil? There is no ignition system left and no stock wiring at all, (i dont even have keys or a place to stick a key in).

Sorry i never did mention the age, i believe it is a 64', at least according to the wiper motor stamping, and its the 1275cc motor, (from what i know).

[dklawson]

No, you do not make a ground connection to the coil.

Succinctly, the current flow is like this (for negative ground cars).
Current "in" on the coil (+) terminal.
Current "out" of the coil on the coil (-) terminal via a wire going to the distributor.
Inside the distributor the wire coming FROM the coil is connected to the moving arm of the points as is the lead on the condenser.
The "base" and fixed side of the points is attached (via a small internal wire) to the distributor housing.
When the points are closed, current flows through the coil, through the points, and to earth, thus charging the coil.
When the points open, the path to ground is lost and current stops flowing. When that happens, the magnetic field in the coil collapses and a high voltage pulse is created on the high-tension terminal of the coil. That's what makes the spark.

Therefore, you want to wire this up where battery (+) is connected to coil (+). You connect battery (-) to the engine block. The distributor gets its ground through contact with the engine block.

Do not forget to disconnect your battery when you are done. If you leave the battery hooked up and the points are closed, about 4 Amps will be flowing through the coil and this will discharge your battery quickly.

[copperhead51]

Ok cool! Thank you!!! Much appreciated

Now i do have spark at the points, and still nothing to the plugs, I lightly sanded the rotor and all the contact points in the distributor cap, and still no spark. The cap looks good and so does the rotor, and i have new plugs and wires. So I don't know why there is nothing at the plugs.

[moss6273]

I believe you added to another thread that was live
http://www.theminifo...7
In my reply, I listed a step by step trouble shooting guide to your problem.
Basically, if you are getting a spark across the points, you should also get a spark at the plugs. If not, disconnect the HT lead from the dizzy cap and place it close to ground.
With ignition on and dizzy cap off, if you open the points with your finger nail, you should get a spark at the HT lead if the coil is good. If you do, then the problem lies between the HT lead connection position on the dizzy cap and the plugs which points to either a damaged cap or damaged rotor arm. You state that the leads are new, so these should not be a problem. Therefore, rotor arm and cap are the likely culprits.
Keep us posted on your progress.
P.S. it has suddenly dawned on me, is your car positive or negative earth?? Does it have a dynamo or alternator?? If you are unsure, swap the + & - connections around on the battery and see if you get a spark.

[dklawson]

IP.S. it has suddenly dawned on me, is your car positive or negative earth?? Does it have a dynamo or alternator?? If you are unsure, swap the + & - connections around on the battery and see if you get a spark.

If the coil were "backwards" relative to the earth of the car, you would still get a spark, just one with less energy. Keep in mind that all cars with generators/dynamos were not positive earth and many that were have been switched to negative earth. So the presence of a dynamo is not necessarily a good indication for which earth the car is.

With spark across the points you should be switching the coil on and off. Follow the tests that Moss6273 suggested. One additional item that could be causing the problem is if you or a previous owner left the distributor loose in the block or way out of position. The position of the distributor controls the ignition timing. If it is WAY out, you may be firing the coil when the rotor is not pointing towards a terminal in the dizzy cap. If you don't know how to static time the engine, you can download the PDF in the link below for guidance.
http://home.mindspri...taticTiming.pdf

For a printed copy of a troubleshooting guide for the points and ignition system, you may wish to download the PDF in the link below.
http://home.mindspri...tsIgnitions.pdf

Lastly, this may sound stupid but I have to ask. You have mentioned previously how you wired power to the coil. You HAVE connected power to the starter motor and are performing your spark checks with the engine turning over aren't you? If you are trying to get spark from the plugs simply by opening and closing the points, you are not going to have much luck. The rotor is basically a rotating switch contact. It directs the high voltage for sparks to the spark plugs based on its gear driven position which is synchronized with the camshaft. If the rotor isn't turning, you will not be able to direct the voltage for the sparks to the spark plugs.

[buttercup]

Hi 

just a quick question related to this; i had my austin mini city 998 running fine once I had remembered to attach the plug leads correctly. Then the engine died. I have checked for continuity with the coil - ok. There doesnt seem to be power going to the coil if i use my multimeter. I do have 12 volts going into the fuse box side. 

Fuses are all ok. I am assuming I have a bad earth somewhere?