Starting issue

[tttuba]

So I have a 47 gmc with the stock 6 cylinder. It has been changed over to 12v system and I have rewired it. Everything good there. I switched it over to electronic ignition with a Pertronics system which basically eliminated the points. Required no mods to the distributor just bolt on. It ran kind of rough after that but it ran, Couldn't hit the gas hard without a backfire, So decided to rebuild the carb as it was filthy and leaking gas. Rebuilt it and still cant get it to run right. Thought maybe did something wrong in the rebuild so tore it apart again. Still leaking but that I can handle. Now it is a no start at all. Pulled a plug and tried to see if I had spark by grounding the plug and no spark.
So unfortunately I have two possible issues with the carb and now the ignition.
The coil is a 12v coil with an external ballast resister. Per Pertronics coil needs to have at least 1.5 ohms resistance which I confirm has 1.7 ohms without the resistor. Don't know where to look next. Possible coil, ignitor system or something else. Any help where to look next would be appreciated.

[dwcsr]

If it ran with the old dist re install it and see how it runs, fix the carb issue and then go after the pertronix install. it almost sounds like you have a plug wire crossed. or a broken wire

[coralhead]

Was the timing set correct and the vacuum advance working properly?

[tttuba]

I checked and timing at TDC. I don't know how to check the vacuum advance. I suspected that too when it would backfire stepping on gas when it would actually run.

[OrrieG]

Back fire on acceleration is a timing issue. You can check the advance with a timing light. Set it for static with vaccuum disconnected from dist and plugged. Reconnect the vacuum, when you accelerate, the timing should change to full advance. Vacuum gauge will allow you to check for actual vacuum from the fitting to the distributor, adjust timing for best vacuum, vacuum leaks. Older Chiltons have a full section on using a vacuum gauge to test and set up an engine.

[tttuba]

Thanks I will try that when I get it actually running. I have narrowed the problem down a bit. I know gas is getting to engine but I dont think I am getting spark. Pulled plug and attached wire and laid it on the engine and NO SPARK. would explain why smelling engine flooded. So I am thinking either coil went out or Pertronics unit went bad. Although the Pertronics unit is not that old. May have left the key on for a while once while engine not running. May have fried the coil or the unit.

[coralhead]

Make sure that your battery is fully charged. After all the cranking that sounds like you have been doing will really draw the battery down. Make sure the timing is close by setting #1 at TDC on compression and make sure the distributor timing is close. I had a similar issue and found the battery to be low. Is the ballast resistor bypassed? It will need to be.

[tttuba]

I am keeping the battery charged. I have also gone so far as to replace the coil. This time I bought one that does not require and external resistor. Still no spark. So either not getting power at all to ignition which I will try today to track down or the electronic ignition unit went bad. Nothing else in there to go bad. Thanks for all the suggestions. Will keep trying

[booger1949]

i just ran across the same thing in a 58 impala an i can tell u now get your money back on that an get you an electronic dist, this guys coil was gettin so hot that u couldnt touch it an it would make the car do the same thing as your truck, so we changed the coil to a bigger one an ran a heavy hot wire to it from the battery an no good, the timing wouldnt even get rite, an at first he thought it was the carb, but checked that an it was fine, so i boiled it down to the pertronics, so we checked the internet an low an be hold a bunch of people r having the same prob, an having problums with talking to the people that make pertronics so we bought a electronic dist. an solved his problum, so good luck

[mr48chev]

The guys at Pertronics are pretty good about helping people sort out their products.

The selling point of that setup is that you can pull it out an stick a set of points and condenser back in and go if you have problems with it and right now I think that is what I would do. Put a good set of points and condenser in, set the points and fire it up and get it running right and after it is all sorted out and the carb is working right and NOT leaking worry about the Pertronics setup.

My best guess is that you either fried something by leaving the key on or have not connected everything correctly.

One other person you might run this by is GMC Bubba http://www.lindertech.com/bhrs/
He rebuilds vintage distributors and sets them up with electronic ignition for a living and for a fairly reasonable price will do the distributor a guys sends in and return it fairly quickly.

[tttuba]

Cool thanks for the lead I may just go down to the parts store and buy some points and condenser. I did check and there is power to the lead for the ignition unit but haven't gone further. Too many other things tonight.

[OrrieG]

Nothing wrong with stock points and condenser unless you are going to rev the beans out of it and engine itself is in good shape (plugs are not oiling up, etc.). Over on the stovebolt.com site there is a tech article on converting a modern 6 cyl HEI to fit in the old 235 engines. Might apply to your GMC too.

[tttuba]

Just want to clarify and make sure I am not slamming Pertronics. Whatever is wrong with my no start is my fault not theirs. I am just looking to get this running. Before I buy another one I want to make sure I have everything else correct. Gets expensive fast if I have to keep buying units because I dont have things right. Reminds me of one time when I was fixing up my 65 mustang. I rebuilt the motor..when I was 16... and didnt know there was a pilot bearing in the back of the crankshaft. That 5.00 part cost me 3 transmissions and lots of my time. Back then I could get a trans for 75.00 but that was a long time ago.
Well it is the weekend again and I have some time so back to the drawing board and finding out what is wrong.

[tttuba]

Wooo Hoooo got it running today. Rough but running. Replaced Pertronix unit with the old points, new coil and new plugs. Will get it tuned up better then go replace the old Pertronixs unit and see if it will run. If not I will get another one. Again probably my fault on why it went bad if it is bad.