Today after driving for five miles running strong, top down & enjoying a great cigar - while stopped at a light the engine shut off like I'd turned the key off. WTH! After cranking/pushing (poor starter) into a parking lot and performing my shade tree troubleshooting I called for a roll back. I had plenty battery cranking power, removed air cleaner saw gas squirting in the carburetor - it cranks over fast just wont start. Sooooo I figure its a bad coil - after ten minutes I tried starting it again and it started up. So I drove home and ordered a new AC Delco coil & condenser from Rockauto. The reason for my rant - do any of you folks have suggestions on anything else I should / could check if is not a defective coil? Thanks in advance.

Base car / 350-300 / 4 speed

 

You never removed the cap and rotor to check them and the points?
did you use a voltmeter or test light to see if you have power at the positive terminal of the coil both in the run position and while cranking?

 

Thanks MelWff - No points - distributor was converted, although I did not pull cap or check rotor. I did not check the positive side of the coil with either meter or light - but now that you mention it I'm going to try using my test light - thank you. The light will tell me that I have power from the ignition switch to the coil and I can eliminate that portion of the circuit as being part of the problem -correct? (Its been to long - I don't know anymore.)

BTW - I used to live in Vernon, CT is a beautiful state - I worked for Pratt & Whitney and was transferred in 1999, moved back to FL in 2008.

 

You said you converted the distributor to what?

HEI distributor, petronix, etc?

Reason I ask is that the 2 most common failures with the GM HEI is either the coil or the control module in the cap. Either one will work intermittently if going bad or defective with heat and will work again once cooled down......

 

JB. - I didn’t convert the distributor previous Owner did - it’s still the old distributor gear driven for the tach, old cap & rotor but has no points and the module I believe you mention. I’ve ordered a GM cool & capacitor (outside of coil) from Rockauto. If I still have a cut off problem I’ll order the module inside the distributor. Thanks for your help and insight as to what else could be causing my problem.

 

The only pupose of the condenser on the coil is radio interference, you dont need it for the engine to run.

 

I thought that was the case that it is for noise suppression but I bought a replacement ($5) anyway, even though the radio is not hooked up.

 

Get rid of that crap electronic conversion and put the stock points and condenser back in it:
NAPA CS786 for the points
RR175 for the condenser
NOE 6651133 for the screw set

It will run reliably forever.

The worst part of your experience was sitting there with a fine cigar, looking cool, and having the car die. That is a human tragedy, and I feel for you.

Lars

 

Terrible experience. I didn’t remember that car being such a bear to push - but then again I wasn’t 66YO back then either. Fortunately and much young guy can to my aid and helped push, a tremendous help while I fought the power steering trying to turn.
Actually I like the current set up - first ignition issue since I got my car back in 2012. I ‘m not sure I could set points & dwell at this point. Although if it happens again I may have a shop convert it back to original. Hell I’m just getting refreshed on what a coil does.

 

[QUOTE=lars;1600393532]Get rid of that crap electronic conversion and put the stock points and condenser back in it:
NAPA CS786 for the points
RR175 for the condenser
NOE 6651133 for the screw set

It will run reliably forever.

The worst part of your experience was sitting there with a fine cigar, looking cool, and having the car die. That is a human tragedy, and I feel for you.

Lars[/QUOTE
]Have to agree with Lars. I tried an electronic module a number of years ago. I was enjoying a Sunday drive through the countryside of Oregon with my wife, the car abruptly died and left me at the roadside. I removed the air cleaner to look down the throat of the carb. Fuel was not the issue. I knew immediately it was the electronic module I had put in the distributor. I went back to points with no regrets. Simple to set,reliable, and car runs fantastic!
Norm

 

This happened to me 3 times since I "upgraded" to an HEI distributor.
All 3 times, it was a matter of a disconnected hot lead to the HEI: Twice when I kicked the lead connection at the fuse block (clutch foot + heavy boots = CLUTZY McCLUTZ), and once when the opposite end of that same lead came disconnected from the underside of the HEI module.

 

Happened twice for me as well since 1983 with the 78. First time it was the OEM control module...let cool down and ran fine until I changed the module. Second time was 2005, cruising down the highway at 70 MPH, engine died with a DUI high voltage HEI coil....Determined that the engine was getting fuel. Car died on the highway near where a friend lives close by. Sent him to autozone for a module and coil. Changed the coil on the side of the highway..fired right up......off I went.

 

It's a Mallory. So I changed the coil to a Delco - took three five mile trips near my house and the car ran fine. So I splurged and added a new distributor cap, rotor, plug wires & an air filter another test ride and car ran great, Today I drove thirty five miles to a car show 65-80MPH no issues... heading home middle lane I95 at 70MPH five miles from the show 'CUT OFF'! Pulled over to the side of the road lifted the hood scratched my ***, shook my head, saw nothing out of place lowered the hood - got back in and it started up like nothing happened. Drove the rest of the way home uneventful. So now I'm considering replacing the ignition module as you'd mentioned. Can anyone make other suggestions for me to check/replace? Other than going back to a points set up.

 

It's a Mallory. So I changed the coil to a Delco - took three five mile trips near my house and the car ran fine. So I splurged and added a new distributor cap, rotor, plug wires & an air filter another test ride and car ran great, Today I drove thirty five miles to a car show 65-80MPH no issues... heading home middle lane I95 at 70MPH five miles from the show 'CUT OFF'! Pulled over to the side of the road lifted the hood scratched my ***, shook my head, saw nothing out of place lowered the hood - got back in and it started up like nothing happened. Drove the rest of the way home uneventful. So now I'm considering replacing the ignition module as you'd mentioned. Can anyone make other suggestions for me to check/replace? Other than going back to a points set up.

 

I may go back to the points set up - I'm reluctant because I wouldn't be able to do the set up myself.

 

My 77 ate four or five ignition modules before I figured out what the problem was (I think). I’m pretty sure the pick-up ring went bad and was frying the modules one after another. I didn’t have time to rebuild the distributor so I bought and installed a new one and haven’t had a problem since. I’ll get around to rebuilding the old distributor at some point, then I’ll have a spare on the shelf when/if I need to do it again, but I have to agree that the ignition module on the HEI distributors are dodgy at best. Most people running them carry a spare. They’re easy to change and the spare should at least get you home. If you keep the HEI set up, spring for the higher quality module(s). As with just about everything else, the Chinese ones are junk.

 

Thanks for the info, I'm going to try a new module along with tracing wires for a short or loose connection somewhere.

 

FWIW-I have been using the below inplace of the standard GM stock type module in my HEI for abut 20-25 years with no issues. This looks like the one I have but it was made by someone else back then that mallory must have bought...I remember paying back then about $70 for it....

https://www.summitracing.com/parts/msd-83647/overview/

 

Ages ago I had Mallory Unilite with an big Super Coil (as i bought it) when I had that same problem it turned out to be a coil. I'd be driving around it would just die ....so I'd open the hood to eyeball it ...never did find anything, but after opening the hood it would start. Turned out it was the coil (one of those monster yellow supercoils). I replaced the coil and it never happened again.
I figured that when it really got warm under the hood my coil was overheating and failing..... as soon as I opened the hood it would start cooling down and then restart.

Eventually the Unilite distributor failed (not sudden either-- a slow agonizing troubleshooting death) also so I replaced it with an MSD-8572 tach drive Distributor since I already had an MSD-6 box. Since I got the MSD-8572 I never had any more ignition failures due to components. The distributor rusted inside like a POS, but it has always worked. I now have the 8572 locked out and I'm using a 75-77 electric tach and I'm controlling the whole thing with an EZ-EFI 2.0...... that's not relevant but I mention it since I've had MSD 8572 disributor for 20+ years and neither it, nor the msd 6 box, has ever failed me.
(PS- that MSD 8572 did corrode terribly inside and I ended up cleaning and oiling it, and then cleaning it and POR-15ing just to try and stop the corrosion---- but it has not failed me in 20+ years).

 

Well, well, well..... look what I discovered under wraps in my wiring harness, a burnt up fuseable link. I’m confident this is what’s causing my intermittent cut offs. Lucky find.