No Spark

[MadRiver]

Howdy all,
I've had a somewhat frustrating day with my BT7. She hadn't run in a couple of years, but after I drained the tank, rebuilt the fuel pump, cleaned and rebuilt the carbs, and put fresh gas in, she started like a charm. I drove her a bit on Sunday, and then parked her in the garage, quite satisfied with myself.

I went out today to take her for a spin, and she turned over nicely, had fuel, but wouldn't start. She had fuel, but no spark. I checked several plugs. I replaced the coil with a new spare, still no spark. The prior owner had installed a Pertronix ignitor, which so far has been trouble-free.

Any thoughts from the collective wisdom? Thanks in advance.

Bill S.

 

[Gliderman8]

Did you happen to leave the ignition "On" without the car running for a period of time? I ask this because the Pertronix (I have it in my car) could possibly burn out if the key is in the "On" position and not running.
Make sure you are getting voltage to the coil and that your rotor and cap are OK.

 

[steveg]

If the Pertronix is fried, the label on the unit will be blistered.

 

[Keoke]

I agree with Gliderman8:

Do not leave key on when engine is not running , as during testing

 

[Peter Arakelian]

Check the rotor.

 

[Healey Nut]

Check the little thin white wire on the battery isolated switch

 

[Scottswim]

Yes, the battery cut off switch in the boot might have malfunctioned. In the OFF position it shorts out the ignition power to ground, but sometimes it grounds it out even in the ON position. I cut off the wire (white with black stripe I think) at the switch and taped over the end. You would lose the hot-wire prevention, but that was rarely used anyway.

 

[MadRiver]

Yes, the battery cut off switch in the boot might have malfunctioned. In the OFF position it shorts out the ignition power to ground, but sometimes it grounds it out even in the ON position. I cut off the wire (white with black stripe I think) at the switch and taped over the end. You would lose the hot-wire prevention, but that was rarely used anyway.

Thanks for the advice. Do I have to change anything else?

 

[Madflyer]

Spark Fuel Air that's all you got. Check fuel filter again. try a new wire from battery to coil. Check Dis cap even a small amount of moisture will kill it spray with WD 40 and wipe dry. also try starting fluid in air cleaner . in any order Try with battery charger on. low battery cold oil will take all the AMPS the starter needs not enough for coil also. Try if you can role start and pop the clutch in say 2nd gear. If it ran then it should run now. MF

 

[Bob_Spidell]

If a Pertronix was installed, the coil grounding wire might have been disconnected (IIRC, the instructions call for a separate ground wire at the coil since Ignitors switch current 'upstream' of the coil, not 'downstream' as with a points system). When I installed a Pertronix, I switched the leads on the cutoff switch so the coil is grounded in the ON position, and open in OFF--same as the big lead to the battery--preserving the 'anti-theft feature (such as it is).

My guess is the rotor, as they can fail suddenly with no warning.

 

[DerekJ]

Pertronix has died, they either work or they are dead. Not sure how you test them, somebody may chime in.

 

[jimmyr]

Do not jump the battery to the coil as this is not how the Pertronix system works. Measure the voltage at the coil when cranking to see if the Pertronix is pulsing the coil. Otherwise as said previously, the Pertronix system may have failed.

 

[MadRiver]

Howdy all. Ok. I've removed the black and white wire from the battery switch and the coil. She continues to turn over fine, but still no spark.

I removed the Pertronix system with the old fashioned points, condenser, etc. I had lying around. Still no spark. I replaced the coil, and still no spark. I replaced the rotor, put in new graphite into the cap, and still no spark.

I've replaced both fuses, and still no spark at the plugs, or when I open and close the points. This one is a sticky wicket. Any additional wisdom would be greatly appreciated.

 

[jimmyr]

Try using a voltage tester light or a voltmeter, and determine where the 12V power is missing. The fuse, the coil, the ignition switch, etc. Then trace it back as to why no power. If that is all OK, then look for something inside the distributor that may be broke. Points grounded, wire broke, insulator cracked, etc. The ignition circuit is quite simple, so find out what is missing and correct it.

 

[Madflyer]

How about a wire on your key switch or Key switch its self. MF

 

[Bob_Spidell]

What kind of plug wires are you using, original stranded copper or aftermarket suppression type? See if you have secondary spark coming out of the coil; not sure what you'd use, do you have some spare spark wire laying about? The stranded copper wires with a stock coil typically just used some of the copper wire wrapped back on the wire, with a cap to hold it in place (I put small brash washers on the coil end with a sheet metal screw into the stranded wire to ensure contact). Aftermarket plug wires usually have a carbon core that can be broken.

 

[nevets]

I've encountered the frustrating no-spark gremlin from time to time. Once, I discovered that the coil to distributor wire was not making good contact where it connects to the coil. On other occasions the problem has been incorrect stacking of the wires/insulating washers on the points post (grounding out).

 

[CaptRandy]

You installed the old points, is the plastic isolator in correctly?

 

[Bob_Spidell]

Any update on this?