Vehicle does not start and has a strong swing. No fire on spark plugs leads. Tested coil and is working. What else is causing the problem ?

You can test the coil and wires using a test plug outside the cylinder. The theory is, any car, truck or military vehicle in the world can fire a spark plug under compression on 30kv in all required conditions.(30kv = 30,000 volts). So you use a calibrated 30kv test spark plug to make sure the coil and associated secondary components can make 30kv and get it to the test plug and fire it across a measured gap. if your test plug consistently fires, then the spark plug if it is not improperly gapped or physically damaged...must also be able to fire the vailable provided spark. You can test the spark burn itself using a labscope and watch what it did or didnt do. This does take expensive equipment and alot of practice. I wont go into the details as the class I teach on it takes 8 hours and barely scratches the surface.

From coil, you will get continuous on, as the timing light sees no break between pulses.
This means coil is working.
Coil feeds distributor which feeds to each plug in sequence.
To test plug-leads, you can put the pickup sensor of timing light over each plug-lead - no need to remove plug-leads from plugs.
Whichever does not fire the strobe light is a dud cable, if any.
You can also pull off a plug-lead and hold it near the engine block.
Use thick dry cloth or gloves or you could get a shocking surprise!!
If spark jumps when cranking then lead is ok.
Do for all leads.
Maybe distributor if mechanical points or electronic ignition is faulty.

Cold starting misfires can often be caused by either tired high tension spark plug leads or ignition coil packs. If replacing leads, then replace with a full, new set. Coils can be changed individually, but it is often the case that if one has failed, then the others aren't far behind. Some cars have individual coil packs on each spark plug. Some cars have a single pack for all plugs and some have coil packs which may control two or more plugs.

To check for a misfire (ignition failure) follow these steps:

(Cold start) (Use a pair of insulated pliers)

1) Start the vehicle

2) When the vehicle starts misfiring, disconnect plug leads or coil pack connections one at a time. If the vehicle idles even more roughly, then that plug or pack should be considered fine.
Replug each connection before disconnecting the next one. Once you disconnect a plug lead or coil pack connection and find no difference in poor engine running, then you have likely found the offending cylinder. Check the spark plug condition, lead and/or coil condition and connections on that cylinder.

3) Replace components as necessary.

I would like more information on your problem. If the engine turns over slowly at first and after starting swings over faster, you could have a battery on its way out. Have a battery specialist test it.
If the engine swings over fast but does not fire immediately you could have fouled spark plugs. When last did you replace them?
You could also have bad spark plug leads - they tend to rob the plugs of spark and this is only noticeable at start up. When the engine is warm it does not affect the spark enough for you to notice.

There's a fuse for the igntion, if it's blown it would cut power to the coil, check to see if the coil is firing by putting the coil wire [ make sure the ciol wire is good, they are known to fail ] close to a grounded part of the car. if it's working, then it may be a bad rotor, if not it may be the coil.


It would be good to list what the vehicle is.

no combustion or no compression? timing chain broke? you did not supply enough info about what you tested.or how. remove a spark plug wire if you dont like shcks take an old spark plug two alligator clips and a piece of wire attatch to the hex metal body of this old plug and connect the wire you just removed run the starter while watching for strong!!! spark.you can have a weak spark and no start=bad coil.i think but maybe wrong that this vehicle still uses aignition module located somewhere on the fender.find a parts locator maybe at the library. this module was aproblem for decades.have fun.

I would say replace ignition coil, that might me the problem, otherwise it can be the ecu, which might have some electrical problems not allowing the car to stay running. Good luck.

No spark to the coil or is it no spark from the coil? First verify that you have 12 volts to the coil when you turn ignition switch on if not you will never have spark from the coil going to the plugs. If you do have 12 volts to the coil and still no spark you have a bad coil. To see if the coil is firing, unplug a spark plug wire from it's plug and hold it to a chasis ground while attempting to start the vehicle. There should be a strong spark and popping sound. Remember to wear leather glove or thick work glove if holding the wire by hand to avoid shock. If there is a strong spark then coil is good.

Sounds like you have your timing off. If it is backfiring, that means that 2 of your wires are crossed, causing the plugs to fire on the exhaust stroke versus the compression stroke. Recheck your timing.

Many possible causes. Spark plugs, HT wires, Distributor cap or rotor, Stale fuel, Ignition coil or a fuel clog somewhere.