Hello,

I do not post very often, but I am ALWAYS on this site looking for wisdom. I have been doing a rebuild of my 83 Z28 for about a year now, and finally today was the day to start the engine. I put in a carbureted GM 350. It was all hooked up properly (so I though) and when I turned the key it fired right up. It ran really good and I was very surprised that a super shade tree mechanic like me could get it first shot. Well that is all beside the point.

We (my wife and I) noticed that it was leaking transmission fluid and decided to kill the engine before it made too much of a mess. When I switched the key to off, the engine kept running. I freaked out for a bit, but then disconnected the battery, then the power to the distributor which finally killed the motor.

I am pretty sure that that I have messed up on the wiring of the starter, but who knows. Can someone please throw me some bones and help me get this thing under control?

Jesse

 

A starter only needs 2 wires to it to work - the pos batt cable, and the signal wire from the ignition switch (purple wire). Any other wires connected are just where the manufacturer connected wires to get a 12v connection - usually fusible links.

Starter solenoid will have 3 terminals on it, one smaller one, and two larger ones. Usually, the larger one that is closest to the actual starter housing itself has a metal tab connected to it that runs into the actual starter housing. The pos batt cable (and any other fusible links) will attach to the other large terminal. The smaller terminal gets the purple wire (signal wire), and ONLY that wire. There are no ground wires to a starter - it grounds itself on the block.

BUT - I don't think that has anything to do with your continuous running. Wiring wrong may make the starter motor itself run constantly, but not the car's engine. And if the starter was running the whole time the car was running, it would have ground off all the flywheel teeth or starter gear teeth, as the engine runs much faster than the starter ever could (there would have been terrible grinding noises).

 

If you are using conventional ignition, I can see where your problem might be. On conventional points style ignitions, a resistor is used to reduce primary ignition voltage once the engine is started. This is done to increase the life of the points. For easier starting, there is a return/bypass circuit from the starter solenoid to the coil which provides full ignition voltage while cranking. For this system to work, you need to have an early style starter solenoid with the return terminal. Or use a relay and create your own return bypass circuit.

If you dont have the correct starter solenoid for this type of system, then you may have miswired your ignition return to the battery post of the starter. This is giving you full battery power to the coil at all times. If you are using conventional ignition, I suggest you switch to HEI. The early style HEI with vacuum advance and internal coil is an excellent self contained performance ignition system for any chevy streed rod. These distrbutors are readily available through aftermarket suppliers. Or go with an MSD self contained distributor for a little more money.

Otherwise you may have miswired the ignition switch. Verify that you have power at the coil + with key on or cranking, no power with key off. Make sure that any oil pressure/fuel pump cutoff switch you may have installed with an aftermarket electric fuel pump is not tied into battery constant and the ignition coil circuit.

 

Are you using an MSD ignition box? Sometimes they can keep the motor running after you take the key out, because the residual voltage from the alternator is enough to keep the ignition system going. If thats the case, you need to splice a diode into one of the wires to solve this problem (MSD has instructions for doing this)

 

Hello, Thank you both for the replies. I am not running either a MSD or an old school points ignition. I have an HEI vacuum advance setup as you mentioned. I have been doing some amateur troubleshooting and I am convinced that it has to do with the wiring of my ignition and possible my distributor. I will be testing all of the wires probably next weekend and get it all figured out. I am sure that it is something stupid.

On a brighter note, I fired it up again today and it ran good. Granted I haven’t tried to move it yet, but baby steps right.

Thanks again and I will give feedback on my findings.

Jesse

 

sounds like the ignition switch is shot

 

That is what I am thinking too. I have been doing a lot of reading and it all pretty much points in that direction. I will be whipping out my meter this weekend with the intnt to test all the electric both in the dash and in the engine compartment. Not that I am an expert, but I will be sure to take some pictures and give goot feedback.

Thanks again for the comments.

Jesse

 

Here's wiring diags that might help: http://www.austinthirdgen.org/index.php?pid=19

 

Thanks for the info Newb, I had seen one of those earlier but that one was in much better quality. I will definately use this when I disect the ignition switch this weekend and test it out. However, I can only use some of the diagram, but since my ecm is out, a lot of it does not apply.

Thanks,

Jesse

 

Well,

I was out in the garage all day yesterday and I figured out why my engine would not stop. I hate to blame this on the previous owner, but he had some Frankenstein-esque wiring techniques which caused me to get confused and I was getting power to the distributor straight from the starter. After paying attention and pulling my head out of my rear, I got it moved are the proper way and now I am in complete control.

Now to finish evaluating the wiring, perfect the timing, and get all the gauges working.

I thank you all for your input.

Jesse