1968 Lemans Starting Problem

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2Cool4Words

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I have a 1968 Lemans with an aftermarket Mallory electronic ignition. When I turn the key to start the engine, the starter gets the engine to start but as soon as I release the key to run position, the engine quits. I thought it was the ignition switch so I replaced the ignition switch in the dash but that didn't fix the problem. I ran a jumper wire from the battery directly to the coil bypassing the switch so the engine would keep running when I turn the key again. Could it be something as simple as a blown fuse? Any help would be appreciated.
 
I checked the fuse box and all the fuses are good. Does any body know if the Mallory Electronic Ignition control module can go bad?
 
Could it be that you have a missing ground? The ignition could get ground through the starter motor.
 
What do you mean by a Mallory Electronic ignition, they make many different types. Do you still have points, if not what system do you have infared or magnetic? How many wires are coming out from the distribtuor if you do not have points? Do you have an external box somewhere in the engine compartment, a Hyfire or some other model. Do you have a voltmeter, if so what is the voltage at the positive terminal of the coil when the ignition switch is in the run position?
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I would go with a used Pontiac GM HEI 74 to 80 ( dead reliable and worry free) and dump the aftermarket junk.

Parts are cheap , in stock everywhere and no hassles.

If it aint a race car, you dont need that aftermarket junk.

just my 2 cents........................


Doug in P.R.:cool:
 
melsg5 said:
What do you mean by a Mallory Electronic ignition, they make many different types. Do you still have points, if not what system do you have infrared or magnetic? How many wires are coming out from the distributor if you do not have points? Do you have an external box somewhere in the engine compartment, a Hyfire or some other model. Do you have a voltmeter, if so what is the voltage at the positive terminal of the coil when the ignition switch is in the run position?
Click to expand...

I have a Mallory distributor with no points - not sure if it's infrared or magnetic. How can you tell? I will check to see how many wires are coming out from the distributor and let you know. Yes, there is an external box mounted on the inner fender well - most of the lettering has come off so it's hard to tell if it's a Hyfire or something else - I will try to find out. Yes, I have a voltmeter - I will check the voltage at the positive terminal of the coil when the ignition switch is in the run position and let you know. Thank you for your help.
 
Sounds like the resistor that sends power to the coil when not cranking. The name of it escapes me at this time.
 
back in 1968 there was no separate resistor from the factory. The positive terminal of the coil had two wires running to it, one was from S terminal on solenoid and supplied full voltage when cranking, the other was from R terminal on solenoid and is a resistance wire. The link below may help you diagnose the no start

https://www.centuryperformance.com/...-Mallory-Unilite-and-E-Spark-Ignition-Modules
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The ignition module is a Mallory Hyfire III. I'm going to check the output voltage from the module that goes to the coil. If I get no reading, then maybe the Hyfire died?

maa-630_zpsdbdb7216.jpg
 
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if you have three wires coming out of the distributor using this sheet as a guide, connect the brown directly to ground, green to negative on coil and red to positive on coil. Completely remove the HYFire wiring and try to start. The positive terminal on coil should have the red wire from the distributor and a second dual wire from the car's wiring harness.
http://static.summitracing.com/global/images/instructions/maa-unilitedist.pdf
 
I checked the voltage coming from the wire on the Hyfire IIA control module going to the coil when the ignition switch is in the running position and I'm only reading 3.0 volts. Shouldn't I be reading around 12 volts?
 
melsg5 said:
if you have three wires coming out of the distributor using this sheet as a guide, connect the brown directly to ground, green to negative on coil and red to positive on coil. Completely remove the HYFire wiring and try to start. The positive terminal on coil should have the red wire from the distributor and a second dual wire from the car's wiring harness.
http://static.summitracing.com/global/images/instructions/maa-unilitedist.pdf
Click to expand...

Thank you for your help. I looked at your attachment. Figure 3 is what my car's setup is. If I understand you correctly, my car could run without the Hyfire with making the modifications as you stated in order to test to see if the Hyfire has died. Is this correct? I appreciate your input.
 
yes I am suggesting you remove the HyFire from the ignition system to determine whether it or the distributor is the cause of your problem
 
melsg5 said:
yes I am suggesting you remove the HyFire from the ignition system to determine whether it or the distributor is the cause of your problem
Click to expand...


Well I tried what you told me to do but the problem still exists. I made sure the ground wire was grounded by doing a continuity check with a meter.

I'm stumped. Does it sound like the distributor is the problem? I can keep the engine running when I connect a jumper wire from the battery to the positive side of the coil.

I appreciate all your help. Standing by.
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you are basically saying you have a problem from the ignition switch to the coil if the engine runs with a hot wire going to the coil. Has nothing to do with the distributor. You did check for a blown fuse?
 
Yes, I did check the fuses with a meter that will check continuity. After looking at your attachment, FIGURE 3 to be exact, I am now thinking that the ballast resistor made be bad. Power goes from the switch, through the ballast resistor, and then finally makes its way to the coil. If I have a jumper wire from the battery directly to the coil, I'm bypassing the ballast resistor to keep the engine running. I'm not sure where the ballast resistor is located. Can you tell me where it is located on a 1968 Lemans? Am I on the right track? Thanks again for your help.
 
there is no ballast resistor. The coil positive has a double wire one of which is a resistance wire and is hot when the engine is running. The other wire is hot when the engine is cranking. You should be looking at Figure 2. The reference to the loom resistor wire that comes from the ignition switch. With the key in the run position the double wire that connects to the positive coil terminal should read about 8 to 9 volts.
 
melsg5 is correct that there is noballest resistor on the stock ignition switch on your car, but if figure 3of the mallory installation manual is how it is installed on your car, then yes it sounds like the ballast resistor may be bad. If one is installed. It usually looks just like in the drawing or this link

http://www.amazon.com/gp/product/B0...d_t=201&pf_rd_p=1944687582&pf_rd_i=B000BWE37I

The location will be were ever the person installing it chose to put it. I usually saw them installed on the firewall, or near the Coil.
But if you trace the wire back from the coil to the firewall and do not find a ballance resistor, you may have a bad or miss adjusted ignition switch, or the linkage fron the lock cylinder to the gnition switch may be damaged or out of adjustment.
I have found that balance resistors can be damaged when jump starting a car that has one installed. I went thru at least 10 in my 74 dodge 1 winter. They would fail about 2 or 3 days after I jump started some ones car.
 
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