I started my 1974 Corvette this morning and she ran for about 10 seconds then quit. Not out of fuel. Pulled plug and tested to see if there was fire. There wasn't. I have an updated electronic ignition and I am not sure if it is the coil or the distributer. I am not sure what to do next. I guess the first question is whether or not there is a separate coil or is it included within the distributor cap. How can I determine this? How do I test? I appreciate your help as I am an amateur on Corvettes. Thanks for any assistance you can suggest.

Mike
Alabama

 

here is a diagnosis link

http://www.angelfire.com/empire/auto...osisandtesting

 

thank you so very much. I am going to look-up that inter-net site. One more question, when I removed the plug, I reconnected the wire and laid in on the valve cover. I did not get any spark. Is there something I have missed?

 

plug electrode needs to be almost touching metal, If you could take a pic of your setup and possibly what diagram you used to wire it up , you could get more informed help

 

I am as mechanically inclined as a jackass so this is quite an endeavor for an old 03 MOS. I bought the car with all of this completed so I have no idea of how it was installed. I did place a jumper cable to the body of the plug with the spark plug wire attached and the other end to a ground. No firing of plug when cranked. Could there be a fuse that has blown? And if so, where does one look? I do not even know if there is a coil or not. Could it be locvated within the distributor cap? Thanks for all of your help.

Mike

 

probably not a fuse, if you dont have spark at the plug, the next thing is to see if you have 12volts at the coil. if you have the voltage there the problem is in between there and your plug. simplest is to look for loose wires that are around the ignition parts, distributer, coil, resister if you have one. A cheap multimeter is good if you have one. This is where a picture of what you have would be good. if these folks can see what you see they can sometimes provide a repair instantly. do you have the big cap hei or is the coil mounted off to the side somewhere. if you have the hei, make sure the plugs are attached that go into the bottom of the coil connector.

 

I was reading that link provided above , its excellent, to many big words , but excellent.

 

What type of updated electronic ignition is it? Is it using the original distributor? Is it a later type HEI distributor. Does it have a separate control box for the ignition?

 

EXCELLENT link...thank you for posting...will file that one away.

 

It sounds like the coil. Its mounted on top of the cap. Best to replace the rotor as well. It will take you 15 min to replace. Just make sure to mark your wires so you dont screw up the firing order.

 

Some jackasses on this forum might take offense with that statement.

 

I'd bet money he's already fixed it.

 

Thanks to you all I got the courage to proceed. I removed the the module and took it to O'Reillys where they tested it. Of course it failed but the great salesman suggested we try a brand new module and that, too, failed. I came home determined to find what the heck was going on. You guys were right in having me check the connections as several were loose. In addition, after careful marking, I removed the distributor cap that also houses the coil. I thought the cap, being almost brand-new, looked a little distressed. I examined the rear of the distributor cap and it appeared it had been subjected to a lot of heat resulting in a crumbling. Sure enough, after I removed the coil from the top of the distributor, there was even more evidence of undue heat and a hole extending to the exterior of the cap. I have said the heck with it and I am going to replace cap, rotor, module, and whatever that small round thing is that remembles a capacator (spelling ?). I woulde not have had the courage to do all of this without your help. I have no idea when the electronic ignition was installed nor what brand it is. I am just going to take everything to the auto parts store and let them sort it out. Any suggestions on where to shop? Thank you all very much for your help; I do appreciate it.

Semper Fi!

 

Good for you....always a positive when you conquer a fear. For what it's worth, I always try to reward good customer service, especially in this economy. Having said that, it seems the salesman at O'Reily's went above and beyond. We don't have them in Canada, but if it was me, that would be my first stop. Good luck, and please let us know how it turns out for you.

 

all of the big cap HEI's are pretty much the same , the difference comes with the variations in parts. the previous owner installed an MSD HEI in mine, on line they're bout $130 , it works fine, but I'm sure a new stock big cap hei would be as good. I actually prefer the GM version just for reliability
btw, the msd's are usually on the shelf at most of the parts stores, if you have problems with it you can just return it without having to wait for the mail

 

Seeing as 1975 was the first year for an HEI ignition in Corvette, someone along the way did you a disservice by installing that unreliable unit in your car. You cannot swing a dead cat without reading another plight about that coil-in-cap going bad. One CF member touring France and Italy right now broke down because of the very same thing. I cannot remember the last time someone had a breakdown because his points ignition crapped out...it's always the HEI units that fail.

 

You are so right about the dpendability of this type of ignition. I had no idea that the engine ignition coil was built "piggy-back" style on top of the distributor cap. The heat in there poked a hole through the top cap, above the distributor cap. I have not put anything back as of yet. It is supposed to rain tomorrow in Alabama and that will give me time to replace all electircal components. Someone else posted a thread regarding their mechanical tach, which I also have but there, of course, is no connection for the tach in this type of Delco Ramy distributor cap. Do they make an HEI distributor cap that will accomodate a mechanical tach cable? Thanks again for all of your assistance; it is like having a mechanic on call.

Semper Fi!

Mike

 

He probably swapped in the cheap one due to the price of the tach. drive units . Close to $480, If you are interested in going back to a tach drive and keeping the Hei or electronic internals, you could get a points tach. drive distributer, a tach drive distributer and convert the internals to electronic with an external coil, you can also get one already converted, or you can get an hei set up for tack drive, MSD and DUI come to mind. you will hear several opinions on this subject. There are a multitude of companies that provide these units in one form or another all have their pluses and minuses, hope this helps.
I left one option off, you could have your tach. converted to electronic

 

Thanks, Marine. For the cost of all this, I think I will be tackless for a while. I did put the distributor cap back together and all I have to do now is secure the module and put the cap back on and attach the wires and hope that it starts. If not, I will be back. Thanks for all of your help. When were you in the Corps?

 

late 60's, semper fi