Spark help

[Raul_C4]

My motor turns fine starter pops out and everything but it just can't start. I used an in line spark tester on the first cylinder no light at all . I used a volt meter and everything was getting 12V but one thing I found odd was the negative post on the ignition coil was reading 12V just like the positive side of the coil . Is that suppose to be like that ?
Anyou help would be appreciated

 

[forrest]

My motor turns fine starter pops out and everything but it just can't start. I used an in line spark tester on the first cylinder no light at all . I used a volt meter and everything was getting 12V but one thing I found odd was the negative post on the ignition coil was reading 12V just like the positive side of the coil . Is that suppose to be like that ?
Anyou help would be appreciated

if you are reading 12 volts on a connected ground it's bad. so chase and reestablish it. now a volt meter doesn't take a lot to give a full reading if you take a plain old test light and do the same test does it light up bright? if it does that is a complete open.

 

[Raul_C4]

if you are reading 12 volts on a connected ground it's bad. so chase and reestablish it. now a volt meter doesn't take a lot to give a full reading if you take a plain old test light and do the same test does it light up bright? if it does that is a complete open.

This is my set up now. The negative on the coil is reading 12 volts .

 

[forrest]

This is my set up now. The negative on the coil is reading 12 volts .

Again I resubmit if your ground leg is lighting up a test light connected from a good ground source and ground on Distributor/coil your ground (Black wire bottom middle of page) needs help or a redundant ground.

 

[Hot Rod Roy]

Again I resubmit if your ground leg is lighting up a test light connected from a good ground source and ground on Distributor/coil your ground (Black wire bottom middle of page) needs help or a redundant ground.

? I've read this many times, but I can't figure out what you are trying to say. Is that all one sentence, or several mixed together?


What kind of car is this? It doesn't appear to be a C4.

If you think of this set-up as if it had ignition points in the distributor, the voltage on the negative terminal will be 12 v. when the points are open, and zero v. when the points are closed. The electronic module in the distributor does the same thing, alternating from 12 v. to zero v. as the distributor rotates. You should get a nice fat spark when the voltage on the neg. terminal transitions from zero (ground) to 12 v.

Using a test light on the neg. terminal of the coil won't prove anything.

 

[dougelam]

This is my set up now. The negative on the coil is reading 12 volts .

12 volts on the negative side is a normal non-running value, it tells us that the windings in the ignition coil are ok.

That voltage will drop when you crank the engine over BUT like Forrest stated a 12v test light is a better choice for diagnosing your problem. In that case the light will be on at KOEO and flicker during cranking.

Also like hot rod Roy asked is it a C4 with aftermarket ignition or OEM?
If it's factory you need to say it to get the proper diagnosis!


*KOEO = Key On Engine Off
*OEM = Original Equipment Manufacturer

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[Raul_C4]

12 volts on the negative side is a normal non-running value, it tells us that the windings in the ignition coil are ok.

That voltage will drop when you crank the engine over BUT like Forrest stated a 12v test light is a better choice for diagnosing your problem. In that case the light will be on at KOEO and flicker during cranking.

Also like hot rod Roy asked is it a C4 with aftermarket ignition or OEM?
If it's factory you need to say it to get the proper diagnosis!


*KOEO = Key On Engine Off
*OEM = Original Equipment Manufacturer

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Okay I'll use the test light . And yes it's a C4 with aftermarket ignition . I also purchased an inline spark tester but didn't see any spark on the #1 . The whole motor has been replaced could I be victim to VATS ? I have 86

 

[dougelam]

This is going to sound crazy but just yesterday I went over to my neighbors to borrow a 2 jaw puller for my washer and he was trying to figure out why he didn't have spark to his plugs, he cranked it over and sure enough the spark tester didn't arc. It is a 70's HEI unit.
He had his test light on the pink wire and it didn't light. I took over and touched it the the positive post of the battery and it still didn't light.
Found a good ground and then it did. I asked what started all this? and he said "I came out today and it wouldn't start, checked for spark and there wasn't one" he then said he replaced the coil and ign module with no change. I had him remove the distributior cap to check his work and to diagnose it.
He flipped the cap over, I probed the negative side (tac connecter) for power and the light lit up and flickered during cranking.
As I went to probe the module I noticed the rotor that was on the bench next to his old coil and module was supposed to be on the car.
I assumed he put a new one on, nope he forgot!
He's in his late 60's so I didn't say to much.

Now if you have power to the coil at all times vats would probably not be an issue
What is the brand/model of your ignition system?


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[Raul_C4]

This is going to sound crazy but just yesterday I went over to my neighbors to borrow a 2 jaw puller for my washer and he was trying to figure out why he didn't have spark to his plugs, he cranked it over and sure enough the spark tester didn't arc. It is a 70's HEI unit.
He had his test light on the pink wire and it didn't light. I took over and touched it the the positive post of the battery and it still didn't light.
Found a good ground and then it did. I asked what started all this? and he said "I came out today and it wouldn't start, checked for spark and there wasn't one" he then said he replaced the coil and ign module with no change. I had him remove the distributior cap to check his work and to diagnose it.
He flipped the cap over, I probed the negative side (tac connecter) for power and the light lit up and flickered during cranking.
As I went to probe the module I noticed the rotor that was on the bench next to his old coil and module was supposed to be on the car.
I assumed he put a new one on, nope he forgot!
He's in his late 60's so I didn't say to much.

Now if you have power to the coil at all times vats would probably not be an issue
What is the brand/model of your ignition system?


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Sounds like a character, as far as I am concerned the distributor is assembled properly . I have the MSD ready to run with the blaster 2 coil. I have the Red Hot wire that comes from the battery going into a resistor then that going to positive side of coil. Then I have the tach wire that comes from the fire wall plugged directly into the tach wire that is shown on the MSD wiring directions along with all the other wires that the directions ask for.
I have the old wiring pigtail that I think is the HEI to ECM harness just sitting on the bellhousing I don't know if that maybe part of the problem

 

[dougelam]

Remove the tach wire to the car and test the system as a stand alone

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[Raul_C4]

Remove the tach wire to the car and test the system as a stand alone

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Hmmmmm.... so disconnect the tach wire and try starting the car? What would this tell me
I'm sorry if this comes across as a dumb question but I'm learning as I go along

 

[dougelam]

First off it would tell you if your restoration is a success!
Second it would tell you not to connect the wire back up ☺

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[Raul_C4]

First off it would tell you if your restoration is a success!
Second it would tell you not to connect the wire back up ☺

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Hahaha 6k and 2 years all depending on a single wire!!!