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1969 Pontiac Tempest I bought about 4 years ago with a 400 (non original) engine. Car has been running flawlessly since I have owned it, but tonight, the wife and I went out in it, and as I was accelerating, it bucked and felt like someone turned the switch off, but immediately caught and continued to run. It did this several more times in the next two to three miles of driving, then when I was coasting down a hill, it stalled. Pulled over, and it would crank but not start. waited a minute or two and it started up and ran find for another few minutes then stalled again.

Got it home and it was idling in my driveway while I was looking around the engine compartment. While I was doing this it just died, like somebody shut they key off. I pulled the coil wire and it had spark when I cranked it, put the coil wire back into the cap and it started up again. I did a pertronix conversion two years ago, but I heard that when they go bad, the car will not start at all. I checked all the grounds and the battery cables and they are all clean and tight. Any ideas of where to go from here? I'm now reluctant to take the care our for fear of getting stuck.

Any help is appreciated
 

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I have heard of problems with the pertronix conversions.

If mine, I think I'd either switch back to points, or switch to an HEI. Obviously, the factory points dist will LOOK more original. Points are also MUCH less likely to leave you stranded. They usually give some warning, rather than just killing the engine. Back before the HEI came along, we ran points in everything, for street & race. MANY millions of vehicles used points, including all the '60's & early '70's Musclecars. It is a very reliable system, IMO.

Another plus for using points is that you can keep the plugs wires you have now.

But, if you wanna try an HEI, & can't come up with a good used one, you might wanna try one of the cheap Chinese models. They sell on Ebay for around $50 & less. SOME guys have reported having good luck with 'em. Some say it's best to swap in a good aftermarket module. Some say they're total junk.

https://www.ebay.com/itm/Pontiac-301-326-389-400-421-428-455-V8-HEI-One-Wire-Distributor-Red-Cap-Complete/390817523399?fits=Make:Pontiac&hash=item5afe8a26c7:g:NEUAAOSwUMVaIY~u

But, if you wanna go with a better quality HEI, the DUI brand is considered, by many, the best. They're just over $300, from Summit. Summit sells several brands.

https://www.summitracing.com/parts/dui-51720bl/overview/make/pontiac

https://www.summitracing.com/search/part-type/distributors/make/pontiac/engine-size/7-5l-455/engine-family/pontiac-v8/advance-type/vacuum-and-mechanical/ignition-box-required/no?N=4294944559+4294951349+4294951351+4294951344+4294944556+4294944551&SortBy=BestKeywordMatch&SortOrder=Ascending&keyword=hei distributors
 

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If you got spark, then check your fuel filter. Take your fuel line at the fuel pump, take your gas cap off and blow through with a compressor. I had a similar issue once seemed like vapor lock and out of the blue I decided to do that and I heard something forced through. I cleaned and rinsed my tank years before so I don't know what it was. Never done it again tho.
 

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Pop off that distributor cap and look real good with a flashlight all around the ignition module. Look for oil......if you see oil crankcase pressure is pushing oil up into the distributor. What that then does is covers the thin cellophane cover over the magnets on the magnet ring and on top of the module.

It will cause just those symptoms intermittent stall, as the oil film interferes with the Hall effect magnet trigger. If it is oil you can plug 4 of the five bottom holes in the dist shaft with RTV or drill some holes to relieve that problem. Then you can correct your PCV Breather system as a bad one causes this pressure.

If not oil check the grounds on the module for loose screws to the dist body, they are very sensitive to grounds. Tighten up and clean up all grounds, even battery to engine and engine to frame. You can test the ground on the module with a direct test wire to negative battery terminal, should have very low resistance.

Use an ohm meter on 200 scale, pos of meter to module plate, negotiations meter to neg battery terminal POST, not clamp. Should be less than .2 ohms, if more find the bad or weak ground.

If that is OK recheck gap on module to magnetic ring or lobes depending which model you have. The modules are very sensitive to that gap should be 10 thousands to 60 thousands....usually 20 to 30 is normal. If it gets loose or out of wahack will only Fire sometimes, giving an intermittent problem.

If that is ok verify your ignition wire provides a full 12 volts to the coil and make sure it is not coming thru a ballast wire that drops the module down to 9 volts which is what points need so they don’t burn up. These modules can work on reduced voltage but perform best at full 12 volts.

It is an easy fix with a relay and very reliable if you have reduced voltage from a ballast wire. There are a few ways to fix it

Those are 4 things I would check, if those are all ok could be a weak coil, check with ohmeter and could be fuel pressure as well....

You just have to do some tests:nerd::nerd:
 

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How fresh is the gas, maybe fill the tank from a different station.

X2 on the bad gas. Take a slug of water and it'll do as you say. Pertronix is a good set-up. The earlier units got a bad rap, mostly because if you left the key/power on and the engine was not running, it would burn them out. The fact that it was bucking would have me looking elsewhere. With electronic ignitions, to include HEI, my experience is they either work or don't.

If you have spark, then it is not ignition. Replace the fuel filter just to be sure that is not your issue. Pour a cap full of gas down the carb or give it a shot of ether and see if it catches. If it does, my money is on bad gas. If the car sits for a while, the ethanol in the gas can absorb water over time. If you filled up and the place you went was perhaps low on gas in the in-ground tank or they just got serviced from a tanker, you may have sucked up a dose of water.

If that checks out OK, then I would begin the hunt for an electrical issue.
 

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Discussion Starter #7
Thanks all for the help. I know it's not the fuel as the car does not sputter or fade out, it just shuts off, plus the fuel is fresh.

I think Lemans guy has the answer, but I haven't done those tests yet. I swapped back my old points distributor and car is running fine in the garage. Couldn't take it out last night because of the torrential rain around here, but hope to this evening. Will let you know what finally happens.
 

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...I swapped back my old points distributor and car is running fine in the garage...
"...verify your ignition wire provides a full 12 volts to the coil and make sure it is not coming thru a ballast wire that drops the module down to 9 volts which is what points need so they don’t burn up. These modules can work on reduced voltage but perform best at full 12 volts..."


If you had switched to a full 12 volts, make sure you switch back, while you are using the points. If you don't have the original resister wire, you can buy a cheap inline resister. That's how I ran most of my bracket engines. Had an on/off toggle switch & a direct 12 volt wire, to which I installed an aftermarket resister. I mounted the resister on the firewall, close to the coil.

https://www.google.com/search?rlz=1CAHKDC_enUS777US777&ei=GxM3XabiCM-sswW3lojABg&q=ballast+resister+needed+to+operate+a+points+type+ingition+system&oq=ballast+resister+needed+to+operate+a+points+type+ingition+system&gs_l=psy-ab.12..35i304i39.13156.13156..15415...0.0..0.105.105.0j1......0....1..gws-wiz.......0i71.MXsI_sm9twk&ved=0ahUKEwjm26P6mcvjAhVP1qwKHTcLAmgQ4dUDCAo

https://www.hotrod.com/articles/choosing-correct-ignition-coil/

http://www.pertronix.com.au/troubleshooting.html
 

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Discussion Starter #9
Thanks Big D.

When I installed the pertronix, I kept the original resistor wire taped up and out of the way and ran a switched 12v source to the pertronics, so when I swapped back last night, I just hooked up the old resistor wire and all is good
 

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Discussion Starter #10
Just an update. Was able to get the car out last night for an extended ride with the points distributor. All is well, so I will leave the points in there and decide down the line if I want to troubleshoot and reinstall the pertronix at some point. thank you all for the help
 

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Many years ago I had a Mallory Unilite go intermittent on me. Behaved nearly identical to what your describing, went back to points, problem solved.

BR's,

Mark
 

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Discussion Starter #14
While I still have an original style coil, I kept the pertronix coil in there and it runs fine. I'll be driving it much more this weekend but I'm confident the issue is solved and I will remain with the points.
 

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If it was the Petronix you won’t stall again obviously,....are you running a return line from the fuel pump or carb to the gas tank?

That will forestall any vapor lock. If you do vapor lock and stall and have no return line, then look there.
 

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Discussion Starter #16
Thanks, I am running a return line. Also I had it out for a long ride today with no problems. It's the pertronix unit.
 
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