Ignition problem on my 73 Stingray Corvette.?

Question

Hi, my name is Ryan and i have a problem with obtaining spark form the coil on my 73 Chevy Stingray. I read the article about a person who has the same exact problem as I with his 73 Chevy truck, also posted on this sight. I wanted to know if there is a difference between troublshooting a 73 Chevy 350 truck and a Chevy 350 Corvette. I have very little experiance and will be greatful for any help that can be given.

thanks,
Ryan P.

First of all i thank everyone that replied to my question! I seem to have another concern, fairly simple for u mechanics out there..... I am attemting to detect spark(with cheapy spark detector) straight from the ignition coil from the ignition wire that leads to cap.Is it necessary for the points to be working properly to abtain spark from the ignition coil?If i dont then doese that mean i do not need to have the wire connected to the points from the coil when testing my coil?? Once again i thank everyone for youre help and i greatly apreciate it.

Answer 1

The trouble shooter for the truck and the vette should be the same (on ignition system) .Been awhile since I worked on a 73 chev but If it has unipoints try cranking it over while turning the set screw on the points,the gap may be too small.But also check the cap and rotor for cracks,or carbon tracking.

Answer 2

Boy: if your truck has electronic ignition, which probably has, the next blah blah blah will partially true. But get to the bottom where I write on electronic ignition.
However mad it may look, i suggest you to give this bible a read if you'd consider.
A- The spark mechanism is quite simple. Upon turning the ignition key (and not starting the motor), the ignition coil should have +12 volts on one pin. Check qitha 12v lamp from this pin to chassis. It should light up. The other pin goes to a switch in the distributor.
B- Loose the cable into this pin. Check the cap that has a cable that runs from the axis of the coil to the center of the distributor. Unplug this cable from the distributor. Now put the loose end of the cable to a mere 1 mm. to the chassis. There must be no fuel loose in the nearby. Then get a piece of cable and connect momentarily the loose end of the coil to ground and release. This should make the 1 mm gap spark. If it sparks, the coil is OK.
C- If not, there´s a capacitor shunted with the coil that usually fails. Change it and try again. I've never seen a coil fail, but capacitors many.
D- Now remember the cable you loosed from the coil? Put it once again where it belongs.
Then, keeping the 1 mm. gap, make someone start the motor. The motor will turn but not start. The gap should produce sparks. If not, the switch inside the distributor or it's capacitor have failed. Replace both.
If ok, then another test.
E- Replace the cable from the cap of the coil into the cap of the distributor. Unplug a cable, any, from a spark plug. Do the 1 mm. gap to chassis. Then, keeping the 1 mm. gap, make someone start the motor. This time the motor MAY start. So keep an eye.
If the gap sparks, replace the cable and check other cable. If cable sparks, check another until tested half of them.
If gap does't spark, then the distributor cap (the plastic piece that holds the cables from the spark plugs) might have failed or is greasy. Replace.
Once you have all the cables tested by gaping, the electicity problem is solved. Did you smell gasoline? if so, there´s the probability that the admission system is working and the fuel system is not to blame.
So, where's the problem?
The distribution must be sicronized to the cilyders. Note that the distributor roates over it's axis (a screw is holding it in it's place).
Add some mark to the position of the distributor.
Then, make someone start the motor.
Now Turn the Distributor each time 5 degrees to the right, then to the left. The motor should start by itself. Fix this position. Then, it was misalignment.
That's all about electricity and the motor, the basic method.
The tuning of the distributor's axis is behind todays scope.

If there was am electronic ignition, there's the possibility of it's failure. Quite possible, because its electronic and dusty and rather but gloriously old.
The electronic circuitry replaces the switch inside the distributor. Run A, B, and C, and if C failed, it's the electronic ignition who's to blame. Replace by new one. Not serviceable. No need to run other tests.
Pheww. Going to bed. Me tired. Good luck.
Note: sory for my english. Spelling seems out of order.

Answer 3

If I can remember that far back. I would assume by your note that the coil won`t spark that you have non HEI ignition (the coil is outside the distributer. 2 things to check would be, 1 use a test light, with the key on touch the terminals on both sides of the coil, you should have power on both sides, therfore the in line resistor is ok. The other thing to check would be inside the distributer. Either you have ignition points burnt out or you have a faulty pickup coil. I would hope that someone at some point would have upgraded from points.I hope this helps. By the way, if the motor has not run for a loooong time there is a slim chance that the dist may have siezed and sheared the pin on the drive gear. Unless you are keeping it all original I would drop in an HEI unit. Any gm V8 unit will work.

Answer 4

Here's my trouble-shooting advice.

1.Make sure the distributor is turning, take off cap and turn engine.

2. Check the points and make sure they open and set correctly (Also check distributor wire).

3. Have the coil checked at auto store.

4. If all that works turn the engine with a volt meter on the coil positive side, should be 12 volts

5. If that works, change wires and cap.

6. Still doesn't work it could be a wiring problem, try to hotwire from positive battery to coil 12v + side.

If its electronic ignition then you skip all the point steps and have the coil checked.

Still no spark, you got me.

Answer 5

the ignition systems on those should be the same.chevy knew they had a good engine with the 350 and didn't do a lot of changes on it till many, many years after yours. let me know if you more details on trouble shooting this ignition.

Answer 6

probably the points but you should be able to trouble shoot it the same way the corvettes had different heads and cam but everything is basically the same.

Answer 7

Does it have points or was it converted to electronic igniton?