I have an old Chevrolet Mallory Unilite distributor , type 57, that continues to start the car and runs for about 5-10 minutes then shuts the engine down. My question is — does the module continue to provide spark if it is defective or once it fails it is done? I have replaced filters, coil, resister and still have the same problem. I know the history of this distributor from the internet and the module seems to fail often, but mine has worked for 20 years without any problems. The quadrajet is old but seem to be fine once it starts. I just perplexed over what the problem could be. Any suggestions would be welcomed.
You are wondering why it is now not working and there are probably a thousand people wondering how you had one that worked for 20 years. I've been where you are and I went MSD and never looked back.
Not enough info to diagnos on here , basic fuel ,air , spark , then electrical system , switch , etc. FWIW my unilite is 24 yrs. old & working perfectly..... there's a module test on the net , takes just afew minutes...
I did the test and it seems to be OK but the car does not run for a very long period before it shuts off. I have tested all the areas you mentioned and find no problem. I know it's my lack of knowledge so I was reaching out to someone who is more knowledgeable. I am ready to purchase the MSD system like I have in the delivery. Not much more than the new module.
I've had really good luck with the unilites - knock on wood! - but I do know they can slowly go bad, regardless of what people say. It's like they get hot after a little while and stop working. I also know that if the ground somewhere is corroded and not making great contact, that will mess with them.
I had a problem with one of those, I could only get 6 cylinders to fire out of 8. I fixed it with a stock GM points distributor.
Go to the parts store, buy a stock points distributor, see how long it runs....my guess is, it'll run for years.
Couple questions, does it start right back up for another 10 mins ? Does it have to sit awhile? When it dies can you look down the carb and hit the throttle do the squirters shoot gas? If you pull a plug wire right after it dies and crank it over do you have spark ? Try these first and post back.
the distributor in post 7 was a Unilite conversion in a Mallory dual point. the guy who's car I put the stock GM points distributor in gave it to me. I'll be running it with points
Did the above test and they were positive. 1. Fuel squirts immediately following dying. 2. Engine spark plug wire has spark 3. Starts right up after dying? I think I will try a new module from Summit.
Yep I'd go to module too, I bought a vw pertronix electronic distributor in my 74 & it'd run about 10 minutes and die, wait a couple minutes and fire up again for another 10 & die. Dropped the oem back in run for ever. Sent it back for a replacement and still haven't put it in.
you might try to clean the pickup eye pull out the rotter button wipe out any dirt I worked on equipment that had unilights in them sometimes that's all it took some of those distributers had a lot of hours on them
Sounds like the issue both my Dad and I had with our uni's. Both times it was modules. We learned to just carry a spare after that!
If I'm gonna carry a spare, it's gonna be a set of points and a condenser. Much easier to change out.
Usually when this happens the coil is too low resistance , check the resistance anything below 1.5 ohms is too low for these modules...
When mine broke, I actually stuck a borrowed points distributor back in it to get home! Sent from my iPhone using H.A.M.B.
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