Not sure if this is coincidence or not but, figured I'd ask here. I installed a tach a few weeks back- basic Sunpro mini. I had a few cold starting issues between then and now but, I chalked it up to me not knowing the car yet as I've only had it a few months and drove it less than 10 times. Tried starting it in 40* weather last night and MAN was it difficult. In troubleshooting the other few times, I verified choke is working, no vac leaks and I swapped spark plugs. The old ones looked good but, I figured it's a cheap part so leave the new set in. I did notice the old were only gapped at .030 and I did the new at .035.

I ran the battery dead trying to start it last night and then charged it overnight. I disconnected the tach this morning and then tried starting it. Full pedal once to set the choke and it didn't start... full pedal a few more quick times and it tried to start just as I let off the gas and puffed a bit of smoke out the carb (air cleaner was off). Turned it over a few more times and it did start. Any chance the tach could be preventing a cold start issue?

Also, it seems it only wants to start when letting off the key. Even when it's warm, it seems I can turn over the starter and it keeps turning and then only fires when I let off the key.

Any ideas on whether this could be related to the new tach?
And could it be sign of anything else that it only wants to start when coming off the key on a cold start? Could this be a timing issue?

 

Got a pretty good idea what your problem may be. Your "it seems it only wants to start when letting off the key" is a good clue. I'd say your coil isn't getting 12 volts while you're cranking the engine. If you still have the points & condenser distributor, the coil is hooked up to a resistance wire supplying 10 or less volts. That extra small wire on the starter "r" terminal (if it's still there) shoots a full 12 volts to the coil + terminal only while starting. If you don't have that wire hooked up, you won't be getting enough juice to start the engine, because of the power drain of the starter. That explains why the engine does start when you let off the key. However, if you installed an HEI distributor, you need to run a new 12 volt wire to the distributor, and abandon the original resistance hookup wire and starter bypass wire.

 

Hey 69- thanks for the help. I finally got a chance to look at it some more today and have a quick question. I do have an HEI distributor and the points are gone. When you say I need to run a new 12v wire to the distributor, do you mean the coil + terminal? If you do mean distributor, which wire do I connect this to on the distributor?

Also, I assume I run this from the starter R terminal?

Thanks again

 

For HEI, you want to run a new switched 12v wire. Either find an unused lug on the fuse block, or a lightly used one, that's only on with the key in the run position. You totally abandon the original resistor coil wire, and the wire on the starter R terminal. You should have markings on the distributor cap that says "Batt" and "Tach". Power goes to the Batt terminal, and I'm sure you guessed what goes to the other one!