No start coil ?

[mvent]

68 GTX Points ignition, tracking down a no start problem, spins over fine, getting fuel into carb. 12.7 Volts at battery 11 volts at positive wire disconnected from coil, 5.9 volts at positive side of coil connected, key on, is this right? Thanks in advance. Points are opening and closing with spark, maybe not enough spark?

 

[R413]

Remove distributor. Ground distributor body to car. Remove coil wire from cap and place near metal, 1/4” away. Key on spin distributor And you should have all kinds of spark off the coil wire.

 

[Canadian1968]

That is a bit confusing. 11 volts to the coil +disconnected??? Is that with key on ?
5.9 Volts to positive side with the key ON is to low.

This almost sounds like a classic ballast resistor fail.
Check the resistance of your ballast it should not be more than 1.5 ohms

During cranking your coil should be getting full battery voltage. While running it can get anywhere from 7-10 V depending on the ballast being used

 

[mvent]

That is a bit confusing. 11 volts to the coil +disconnected??? Is that with key on ?
5.9 Volts to positive side with the key ON is to low.

This almost sounds like a classic ballast resistor fail.
Check the resistance of your ballast it should not be more than 1.5 ohms

During cranking your coil should be getting full battery voltage. While running it can get anywhere from 7-10 V depending on the ballast being used

Sorry for the confusion, I have 11 volts at wire going to + coil but not connected to coil, when I connect it to coil and check post on coil its at 5.9 key on both instances. Put a new NAPA ( echlin ) ballast resistor in today but didn't check resistance before installing.

 

[Canadian1968]

Something seems off.

You took the positive wire for the coil, took your meter and connected + to wire and then grounded the other lead of the meter and got 11V ?
Then you hooked up the wire to the coil and did the same test and got 5.9 V

Both of these with the key in " run " position?

 

[mvent]

Something seems off.

You took the positive wire for the coil, took your meter and connected + to wire and then grounded the other lead of the meter and got 11V ?
Then you hooked up the wire to the coil and did the same test and got 5.9 V

Both of these with the key in " run " position?

yes

 

[davek]

1st pull plug wire and see if you have spark, https://koboguide.com/how-to-test-spark-plug-wires-with-screwdriver/

 

[davek]

68 GTX Points ignition, tracking down a no start problem, spins over fine, getting fuel into carb. 12.7 Volts at battery 11 volts at positive wire disconnected from coil, 5.9 volts at positive side of coil connected, key on, is this right? Thanks in advance. Points are opening and closing with spark, maybe not enough spark?

do you have spark?

 

[mvent]

No time to do much today but I did put the test light on negative coil post and it did flash while turning engine over with key, put it on positive coil post and it stayed lit while turning engine over but it did have a pulse to it. Going to get back on it tomorrow.

 

[davek]

they sell these at local auto stores

https://www.amazon.com/Lisle-20610-Inline-Spark-Tester/dp/B0002STSC6

 

[mvent]

they sell these at local auto stores View attachment 1140117https://www.amazon.com/Lisle-20610-Inline-Spark-Tester/dp/B0002STSC6

Picked one up today along with some wire and alligator clips

 

[mvent]

Here's what I have, with test light on (lit) connected to negative coil side reads 10.85V
same 10.85 on positive side with test light on still connected to negative. With test light off negative side is .0V positive side is 6.03V. Have spark from coil to distributor, and have spark at plugs both appear to be weak to me. With jump wire from battery + to coil + I have 11.85V at coil+ side. Negative side reads .43V with jumper connected + to +.
While cranking voltage to positive side of coil is jumping all over 13V 19V 4V 10V 17V etc.
Hope this info helps to get me in right direction as to what part I should be looking to purchase.
Thanks in advance,

 

[mvent]

Here's what I have, with test light on (lit) connected to negative coil side reads 10.85V
same 10.85 on positive side with test light on still connected to negative. With test light off negative side is .0V positive side is 6.03V. Have spark from coil to distributor, and have spark at plugs both appear to be weak to me. With jump wire from battery + to coil + I have 11.85V at coil+ side. Negative side reads .43V with jumper connected + to +.
While cranking voltage to positive side of coil is jumping all over 13V 19V 4V 10V 17V etc.
Hope this info helps to get me in right direction as to what part I should be looking to purchase.
Thanks in advance,

Forgot to mention on Left side (single) wire of ballast resistor has 9.85V Right side ( 2 wire) has 6.37V key in on position

 

[Canadian1968]

So you verified you have spark. But it is weak ( kinda of what I was expecting )

The readings you are getting from the negative side are normal. The way an electronic ignition works and points are basically the same , they just use a different method to trigger the timed spark to the the coil / spark plugs . When the points close in your system it is closing the circuit in the system, and you get a spark . When the point gap opens , the circuit is opens and you will get a 0V at your negative coil. Hence your why your test light is flashing.

During CRANKING you should be getting full battery voltage to your POSITIVE side of the coil. When you let off and the key is run, your voltage should drop to around 7-8 V i believe.

You did a jump wire straight from the battery for your testing. Did you try to actually start the car this way? or did you have the coil wire disconnected from the distributor?

Try the jumper to the positive side of coil see if the car starts.

To me it sounds like getting a big voltage drop someone where in the system between your battery and your ballast.

Your 9.85V on the one side of the ballast shouldn't really be any lower than .8 volts of your battery.

Have your checked your bulkhead connections ???

 

[mvent]

Put the jumper from relay positive wire to coil positive and it fired right up, while running I have 13.7 to positive coil post. So now where's my problem? Could it be battery positive cable?

 

[mvent]

Disconnected jump wire and let it sit for 20 minutes, turned key and it fired right up !
It ran like it was loaded with fuel and stunk until it cleared out. This is hard to admit but maybe it was just flooded ? I almost hope so.

 

[davek]

pull a plug and look at it.

 

[Canadian1968]

I don't think flooding is your problem.

So it started up and ran with no jumper ?? If you can get it to start again and run under with all the factory connections, check and see how many volts you are getting at the positive coil.

 

[Fran Blacker]

Get it running without jumper wire and go around wiggling ignition circuit wires. Bulkhead wires inside and under hood and ignition switch if it cuts out bingo. I would say not battery cable if it cranks fine, could be wrong.

 

[mvent]

I don't think flooding is your problem.

So it started up and ran with no jumper ?? If you can get it to start again and run under with all the factory connections, check and see how many volts you are getting at the positive coil.

13.7 at positive coil post running.