Well an issue has arisen on my 55 Pontiac. Wisdom and advice is sought. It wont start. It cranks over freely, new battery. I've just started examining things. I have a good ground at the points, gap is right, i have 12V at the coil during the keys normal running position. When I turn the key to start, the engine cranks but the '+' side of the coil drops to zero volts. I don't believe that should be the case as it would indicate that no power is being applied to the plugs when starting. I have not checked to see if I have spark yet at the plugs while cranking. I have not checked to see if power is coming from the IGN on the ignition switch. I have not replaced the coil resistor on the firewall, it shows 12v at both sides. Coil, points, condenser, rotor, cap, wires, plugs are all new and oem or better. I have not replaced the voltage regulator ... yet, its in the mail. Odd thing, initially when i got the car, two wires on the starter were twisted together and electrical taped...i put them back to original...I don't wonder if that was a 'hot wire' to make this work or perhaps im missing something. Any thoughts?
Is there a S and an R terminal on the solenoid connect the R terminal to the + side of the coil. Some switches do not supply power to the coil in the start position they rely on the resistor bypass wire from the solenoid to power the coil. Sometimes the engine will catch when the engine is still turning and the key returns to the on position.
That starter wire is a factory provided hot wire, only energized while cranking off the terminal marked I or R.
Years ago I had a 'no start' Pontiac issue, turned out to be a shredded nylon coated timing chain. Not sure what years they were used.
55s have steel gears. It's possible the chain broke/slipped but we always diagnose the easiest stuff first. The every first thing I test is making sure the carb is getting fresh gas...if the gas smells nasty, spray a little starting fluid down the carb and try to start it again. I'll bet a full 60-70% of my "no start" problems with points ignitions is cruddy build-up on the ign, points contacts. Turn the engine 'till the points are closed and with the key "on" [not start].....use a screw driver to open the points and let them slap shut...observe if they spark...repeat until you get a healthy spark with every slap. File points with your finger nail clippers file, Check for proper point gap, [a good starting point is 15-17 thousands], clean any boogers off the contacts inside the dist.cap and check the rotor for cracks/carbon tracking. Start engine
Of course,,, it’s the timing chain The most likely culprit to cause a loss of power to coil in start position would be the timing chain. Starting fluid,,,, fresh gas or grass or ass,,, points,,, yep all cures for loss of power to coil in start position. The “ODD THING” here is where to look first. Possibly following it back to the ignition switch that’s more than likely at fault.
If the ignition system has you pulling your hair out, here's a refresher course that might help get you back on track. https://www.jalopyjournal.com/forum/threads/hot-rod-technical-library-basic-ignition-systems.983424/
After some futzing i've ensured the wires are in the proper place...getting power at the coil now, when i put a tester light on the "-" side of the coil, it will flash while cranking. To complicate the mystery: I did try jumping the coil from the battery, supplying 12v to the coil at all times, didnt make a diff, not even a hint of wanting to live...the timing chain was good when I inspected it. When i get home from work, ill check to see if i get any spark on #1...reviewing the basic ignition link above...ill check the starter switch too as was suggested above and see that im getting 12v at the 'start' position from there. Thanks all, ill update the thread when I try these couple of things!
If the light is blinking on the distributor side on the coil when cranking you have power to the coil ether from solenoid or the switch and the primary side is OK with the exception of a bad condencer..
Great to know...i did install a new condenser, wonder if the new one may be bad? I know its there to shield the points from frying from voltage spikes, ill see if I can get spark at #1 later today and reply to thsi thread.
2 weekends ago I was in NC for my buddies wedding. we were trying to get his Model a sedan Wrapped up so they could drive away in it. Friday night at 11 o'clock, it wouldn't start. chased it down to a new, week old condenser that burned out. Next morning, same thing, no start, another new condenser bad. put that last new one in it and it fired up. On the way to the wedding, it died again. Luckily we had robbed one out of a flathead in the shop to have a spare. swapped it on the side of the road, that condenser was probably 40 years old, works fine and will most likely last the rest of the year. New condensers are garbage.
Oh my, ya in some ways that doesnt surprise me, that several new ones were bad...such bad production values nowadays...I did keep the old one as a fall back, easy enough to swap and test for sure, thanks! Glad you guys kept the old one too!
Go and get a HEI from a newer Pontiac. It will fit perfectly. and it will have a much better spark. usually on the starter there are two wires on the solenoid. A purple wire activates the starter . on the other terminal a yellow wire runs to the positive side of the coil bypassing the resistor.
I have thought of that, I really want to try to get the old gear working...I would love to just HEI it and forget it though hehe. im guessing i could jump past the 'start' on the key by turning it to the running position and kick the starter purple wire with a bit from the hot side of the battery. Hmm...
I have also run across a few bad new condensers recently. About pulled my hair out chasing that stupid low buck fix on my 56 Ford a few years ago all over a crappy new condenser.
There’s a hierarchy of order to follow for this stuff. There may be (probably is) more than one problem to find here. Follow the hierarchy and you’ll catch everything. Or don’t follow the established troubleshooting hierarchy and aimlessly jump around guessing and throwing parts just waisting time and money chasing your tail. You might get lucky.
One thing Ive learned about electrical on any vehicle. Having a good clean ground is just as importiant as the hot side is. Clean every ground and even add another one or two. Running a ground wire from the battery negative terminal to the dist housing will not hurt anything.
Ha, Momma came home today and said her car dash lit up like a Christmas tree. I figured it was a ground somewhere,,,, Engine temp was 150 & ambient compartment about the same. Warm but not burn you really. Check the grounds and one of them burnt the hell out of me, IR gun said it was 280 F. Looks Good and tight But kind of fuzzy inside And between the lug and the chassis. Cleaned that one up and it’s all better. She needs a PM session in the shop. Bad grounds are like mice Lol
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