Troubleshooting no spark

I don't seem to be getting any spark in my E-type, and ignition troubleshooting has never been my strong point. Just about everything in the ignition system is new, rebuilt, or tested.....so here goes.

I'm getting 12.4 volts to the coil from the ignition switch. The coil is new, and measures 3.4 Ohm across the terminals, which is appropriate for a 6-cyl. The distributor came with a used Pertronix when I got it, but I had the unit rebuilt by Jeff, and the Pertronix tested fine, so I'm confident that was good (at the time). The rotor is new, and (I believe) was one of Jeff's heavy duty jobs, the cap is new, the wires are new (Magnecors), and the plugs are new. While cranking over, I have got the occasional "cough", but nothing more than that. I pulled a plug, and held it to ground while cranking, and there appeared to be nothing.

Where do I start from here? I know the easy answer is to throw a set of points at it, but I don't have any handy right now. Is there a test that can be done on the Pertronix to see if it's gone belly-up? Can anything be measured at the distributor cap terminals?

Thanks

Assuming that you have spun the engine while looking at the rotor arm to make sure that it is indeed rotating....several things....

No matter that the rotor arm is "new" even if it is a Jeff part, check it for ground tracing and/or shorting from the underside cup to the dist cam spindle.

Obviously check VERY closely for cracking/tracing to ground inside the cap.

Check closely for any sort of wiring ground once the juice is inside the dist body.

Substitute a known good coil. I know that you have checked continuity but do it anyway. Your mother said that she wanted you to do it.

Take one of the plug wires off and jury rig substitute it for the coil wire. If the engine runs, even poorly without one of the cylinders firing, you have your man.

You do have fuel delivery do you not?

Jack

I'm with Jack - suspect the coil.

Distributor is rotating, and I have fuel.

I'll check the other things tothe best of my ability, thanks.

Same problem yesterday on a B .

The occasional cough tells me its firing. Its likely that the timing is way off (likely 15-25 degrees), and possibly the plugs fouled. If it sputters out the exhaust, turn the distributor CW. If it coughs out the carbs, turn it CCW. Leave the choke half off, to help dry out the plugs as it fires.

Pertronics is a trigger ,so test as yoy would with points OR pull dist
and put in vise carefully/no pressure ,and use batt charger and test light
to simulate eng by protating dist ,,watch for blinking light

A quick coil test.

Take the coil lead from the dizzy cap and hold close to the block (about 1/8"). Have somebody spin the engine and check for spark.

A quick rotor arm test.

Remove dizzy cap, hold coil lead close to the top of the rotor and have somebody spin the engine. If you get a spark, rotor arm needs to go in the bin. No spark is fine.

Ya, Owen is right on here.

Benny, since you dont seem to be getting spark at the spark plugs, you need to then check if you have spark at the coil.

Take the coil wire off of the dizzy end and hold it close to a good ground. The engine head bolts work well for this, but any good ground will do. Have someone cranck the engine, while you look for spark at the coil high tension lead.

If there's spark at the coil wire, then suspect the pertronix unit, or the plug wires.

If NO spark at the coil HT lead then suspect the coil, or coil wire.

This will help you diagnose.

In order to check orientation of the dizzy, get the number one cylinder to TDC and check to see if the rotor is pointing to the correct cylinder. Then check firing order and locate the plug wires in the correct order.

You should also get yourself a timing light and get the timing correct after solving these problems.

Good Luck

B

That's a smart way to check the rotor, but typically the rotor won't misfire until the engine is at operating temp. Its a greta way to test the rotor at the point of the car dying!!!

Benny.............if you have an original Lucas style cap (with the screw on terminals), make sure the wires are fitted properly in the cap (with the little copper slotted washers).