out on a drive and the motor wouldnt restart after shutting off for a second at dominos pizza. towtruck home and it seems to have no spark when cranking , tested by holding sparkplug in jumper cable negative (other neg lead @ batt. neg) . looking in 1971 manual doesnt show the coil location i wonder if its the coil went bad . does anyone have any tips on 1971 455 ignition coils?

 

I am not familiar with a 71 Toronado but the coil had to be very near the distributor on the intake manifold. The other end of the wire in the middle of the distributor goes in the coil so just trace it down. Is there a chance the car has a later model HEI distributor? If that is the case the coil is in the distributor cap.

 

Ignition coils can and do fail but their failure rate is quite low. Check for power to the coil, try checking for spark at other wires. If no spark at the plugs check for spark out of the coil wire into the distributor cap.

Good luck!!!

 

Also, when checking for a spark the battery is not the place to do it. Batteries emit hydrogen gas and a spark will cause them to explode. If you want to check for spark do so at the engine block.

 

YEAH I HELD IT FAR AWAY. I GUESS ITS AN hei , THIS IS NOT COVERED IN THE SERVICE MANUAL. YOU GUYS KNOW WHICH WIRE SHOULD HAVE +12V TO GND WHEN KEY IS IN 'RUN' POSITION?

 

It could be the module also.

 

X2 on the module. That would be the first thing I would check.

 

Power is the first thing I would check, since that costs nothing. Power is applied to the BAT terminal on the cap.

 

HEI is not covered in the service manual because it is not original for a 1971 model. How this conversion was wired is the first question, which again is why I'd verify power first.

 

i love it ,thanks guys. i am unironically a professional union electrician, but i have so many high volt habits that ive learned to have alot of humility about auto wiring.

 

For me I find it easiest to start at the power source (the battery) and work towards the problem area, verifying along the way; especially with ground issues.

 

problem was about 3' back from hei . #16 awg wire and an overheated, failed butt splice. i think the best bet would be to use the lead going to 'batt' to energize a small solenoid that modulates a #12 from battery , then connected to hei. unless the 14v at battery from alternator would smoke the ignition coil, youd have to put in a resistor to lower it to 12v perhaps.

in winter , the michelin ltx a/t (late 90's 1st gen) is a nice tire for the toronado.even stops on ice sort of.
the machine shop owner here in town said that when he worked at oldsmobile in the 70's , they would drive the toronados offroad all the time for construction work, and it had little effect bottoming out /scraping the undercarraige cresting hills etc. thats sort of cool. thx for your help everyone

 

The HEI wants full battery voltage - nominally 13.8V. Do not use a resistor in the power feed. In fact, be sure the original resistor wire from the old points distributor was replaced with copper when the HEI was installed.

 

I use the resistance wire to trigger a 30A relay connecting B+ to the HEI. Been this way since 2011 with no issues.

 

that

That certainly works. The relay, extra wiring, and fuse (you did fuse the power feed to the relay, right?) are just more parts that add more potential failure modes. A simple copper wire replacing the resistance wire and running to the BAT terminal on the HEI does the same thing with fewer parts. I'm a fan of reducing complexity and failure modes.