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car won't start

2K views 23 replies 5 participants last post by  awhtx 
#1 ·
Just swapped out the Holley 600 cfm for a Summit 500 cfm carb and replaced the dash gauges with Classic Instruments. Now car won't start. Cranks over, gas to carb. Float bowls filled up very quickly.

Part of the instrument replacement was a volt meter. I disconnected the ammeter and taped off the ends. Do they need to be connected for the ignition to work? Looking at the wiring diagram, it looks like they shouldn't.

How can I check to see if I have power to the system when cranking? Is this a two person job? I have the original distributor but with a pertronix inside. Car worked before the carb and instrument swap.
 
#2 ·
More info, no spark. Pulled #1 plug and grounded it while cranking-no spark. With key on, put volt meter on + of coil and - of battery, no volts. Did the same while cranking and got 10V of current.

How do I test my coil? It s fairly new pertronix flame thrower.

Should I consider putting my points back in?
 
#3 ·
Update to my update.

I'm an idiot. I had the engine feed wire going to the neg side of the coil. I switched it and now I only have 8 volts across the coil.

New question: I ruined the coil right?
 
#6 ·
Yes, rotor is back and the contacts look good. I had no spark when I had the coil hooked up wrong (+ from dizzy to + coil and - from dizzy AND engine harness to -coil). I switched it to +from dizzy and engine harness to +coil and - dizzy to -coil. Didn't check to see if plug has spark. I assumed it would. I'll check tomorrow.

Just checked coil and still has 1.5 ohms. Any way to test the coil?

What about the dash wiring? Can you start a car without the dash installed? I have a rally pack and that is hooked up. I think if it wasn't the car wouldn't even turn over, correct?
 
#7 ·
The tach in the Rally Pac installs in series with the Pink wire so if it is disconnected the engine won't run with the key in the Run position. It will start with key in the Start position because the coil is receiving full 12V from the I post on the solenoid in Start but it will die as soon as you release the key to Run.
Check the big wire coming out of the coil going to the center of the distributor for spark. Either connect an inductive timing light to that wire or pull it out of the distributor and hold it close to a ground while cranking the engine with a remote starter switch or by jumping the solenoid. Be sure the key is in Run position when you do this and verify the transmission is in Park or Neutral.
 
#8 ·
I double checked the rally pac wiring, its correct.

I have and inductive timing light, so just hook it up to the coil wire (instead of plug #1) and press the trigger while cranking?

How do you "jump the solenoid"? Send 12 V to the post going to the starter? Incidentally, I pulled the coil off and the primary windings show 1.5 ohms but I get 0 ohms from the secondary windings.
 
#9 ·
Testing the coil secondary... ohmmeter to 20k ohms scale... one lead on coil+, the other in the high tension tower. You should have 7.5k to 14.5k ohm +/-....

If you want to "test" the coil, pull the wire from the center of the distributor cap and stick an old spark plug in it and place on a decent ground. Disconnect the coil- (black) wire. Turn the key on. Grab a suitable jumper wire and place one end on the coil- and ground the other end. Each time you remove the wire from ground you should get a spark.
 
#10 ·
I'm getting 9.34, so thats good. I think my coil is fine.

Could it be I flooded the engine since I was cranking it for a bit with the coil wired wrong?

I'll put the coil back in tomorrow and see if I get a spark to the distributor central wire.
 
#14 ·
I did some reading on how the ignition system works. Am I correct: When you turn the key to start, power goes to the S post on the solenoid and out thru the I post and the brown wire which hooks up to the red/green wire and delivers power to the + side of the coil while cranking. With the key in the run position, power to the coil is supplied by the red/green wire.

Would a problem in this circuit explain why I have 9 volts to the +coil when in run and no spark when in start? With the key on run, I have 9 volts to the I post. If I have someone turn the car over and measure volts from the I post to ground would that help?

Even if the Pertronix modulator is fried, I should still have a boat load of spark exiting the coil, correct?

Maybe my ignition switch failed? I got a new one from NPD but they sent me the wrong one and I reinstalled my old on. I'll look at that.

Anyone have anything else I should look at?
 
#15 ·
Even if the Pertronix modulator is fried, I should still have a boat load of spark exiting the coil, correct?
No. The coil works like this. When the points are closed the coil builds up a charge. When the points open the coil dumps this built up charge into the coil wire to the distributor. Replace the points with a Pertronix or other electronic trigger and instead of mechanical points opening and closing you have magic inside the little black box that opens and closes the circuit. If the module has failed then there is no opening and closing of the circuit and the coil doesn't build up a charge.
 
#20 ·
I'm old enough to remember those. Don't know when the last time was I saw one. I also remember when a book of matches would drop out of the cigarette machine when you pulled the knob!
 
#21 ·
The dwell meter just tells you if the gap in the points is correct. That is the one thing I will give Govt Motors credit for- the window in the side of the distributor cap so you can adjust the points with the engine running while watching the dwell meter. And I still have my meter! And my feeler gauges for setting the gap.
 
#23 ·
Found the issue. Blew a hole in the side of the Pertronix module.
749889
Guess this is what happens when you wire the coil wrong. Also from all my readings I realized I have been sending power thru the resistor wire. This car should scream when I get all 12 volts to the coil.
Thanks everyone for walking me thru this.
 
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