AKimball92

True Classic
This is another case of turning over but no spark.

I have performed a full engine rebuild and am attempting my first start but cannot get spark. I replaced the battery assuming the dead cell and max 74% charge was the culprit. A big fat negative.

Nothing else in the ignition system was replaced during the build.

I have 12 V from the coil plus to ground. 12 V from the pink wire at C19 at the ignition switch.

Are there any tests I can do to verify the coil? Is there anything else that could be the culprit? I might need new leads but I am pretty sure they were new prior to the tear down attempting to diagnose the original cause of no start ~5 years ago. I might just need a coil but really don't want to buy one if its not needed.

Edit: I added an engine bay starter button by jumping across the starter leads. It turns it over easy with this with Key On.

Edit 2: My voltage gauge is reading 16V with red light but doesn't seem to move off that no matter the key position or battery hooked up. Obviously the light is off when no battery.
 
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have you looked for the double jumper wire on the coil
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If you have an ohmmeter, the service manual calls for 1.1 to 1.7 ohms resistance for the primary of the coil and 6000 to 10000 ohms for the secondary.
Remember to check the resistor in the distributor rotor too (6000 ohms).

Edit: I have a switch wired similarly, very handy at times.

Edit 2: you could try watching the VM when you turn on the turn signals or headlight switch.
 
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This is another case of turning over but no spark.

I have performed a full engine rebuild and am attempting my first start but cannot get spark. I replaced the battery assuming the dead cell and max 74% charge was the culprit. A big fat negative.

Nothing else in the ignition system was replaced during the build.

I have 12 V from the coil plus to ground. 12 V from the pink wire at C19 at the ignition switch.

Are there any tests I can do to verify the coil? Is there anything else that could be the culprit? I might need new leads but I am pretty sure they were new prior to the tear down attempting to diagnose the original cause of no start ~5 years ago. I might just need a coil but really don't want to buy one if its not needed.

Edit: I added an engine bay starter button by jumping across the starter leads. It turns it over easy with this with Key On.

Edit 2: My voltage gauge is reading 16V with red light but doesn't seem to move off that no matter the key position or battery hooked up. Obviously the light is off when no battery.
Are you using a distributor with points? If so, have you checked the contacts and set the gap or dwell angle? Also, make sure the condenser is good. The coil should fire when the points open if all is well.

An additional note: I'm not sure how you checked for spark but I went through this about a month ago. I hooked up the timing light and it did not fire. I hooked up another timing light, same problem. I finally hooked up a spark plug outside the engine and it fired! Turned out I had two bad Sears Penske timing lights. They had not been used since this car last ran 23 years ago and I suspect some of the capacitors went bad. Fortunately, a friend gave me a fancy MAC light with the dial feature to check advance.
 
Was the ignition system working before you rebuilt the motor, if so we can sort of rule out any ignition component failure to start with.
 
Turned out I had two bad Sears Penske timing lights.
Funny you say that, I also had two of the same timing lights go bad.

Andrew, you can test for a spark from the coil the same way you test a spark at the plug; disconnect the coil high-tension lead at the distributor and place it a couple millimeters from a good ground. Then crank the engine. It will spark the same as a removed plug will - which you should also check.

Several good suggestions already given. One of them is something that isn't always obvious. Many Bosch rotors have a resistor built into them, along the arm between the center post and the metal tip (that transfers the energy to the cap lugs). That resistor often fails, preventing all energy transfer. So even a good coil looks like no spark. And you can't see the resistor to tell if it is bad. Therefore I'd begin with the simple coil test (remove lead), then the same at the plugs. If there is no spark at the coil, then test it with an ohm meter. If there is spark at the coil but not at the plugs, then replace the rotor.

All of this is assuming what Carl said; did everything work before(?) - you did say the reason for the repairs was a no start condition.
 
I would check to make sure everything is put back together first. Sometimes I overlook a harness connector or a ground or something and an engine-out disconnects a lot of stuff. If engine is turning over with starter engaged the ground strap is probably not the culprit. Try and think back during the work if any wires hung up or a harness was yanked on. After a thorough visual check, I'd start tracing circuits for continuity.
 
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If you have power to the coil, then the trigger which grounds the coil and "fires" the power to the plugs is not working for some reason. On a car with points, this occurs when the points close. Don't give up hope, I am sure you will find it soon.
 
Andrew,

I am pretty sure I have the points distributor from my 78 in a box somewhere here at home. Car was running fine last time it was used. Let me know if you need it for testing purposes.
 
On a car with points, this occurs when the points close.
Sorry Eric, the coil fires when the points open and the field in the coil collapses. I used to time my 124 sport coupe statically with a regular 12v bulb; dial in the advance on the crank and turn the distributor until the light just goes out.

Andrew, the condenser (if you have points) going bad will also cause a no spark, it's not easy to test (except for being shorted out, a common failure mode); substitution is the usual proof for these.
 
If you have power to the coil, then the trigger which grounds the coil and "fires" the power to the plugs is not working for some reason. On a car with points, this occurs when the points close. Don't give up hope, I am sure you will find it soon.
Actually the coil fires when the points open causing a large voltage build up in the coil primary (V = L*di/dt) which results in an even higher voltage in the secondary determined by the primary to secondary winding ratio.
 
Glad you agree DL; as the points cycle closed and open, the intermittent voltage works like AC current in the coil, with the coil's magnetic field oscillating, firing the plug as the field collapses, aided by the condenser; point gap (hence, dwell angle) must be in an operating range to make sufficient spark.
 
Wow thanks everyone. I did a few more checks and think i will get a new coil and new condenser. What coil's do you all recommend for a points based system?

The latest checks and updates.

I have a points system with the dizzy on the block. I can't remember which one that is brand wise. I should have a picture here somewhere. Also the gap is pretty much correct. The 0.015 wire feeler fits and the 0.019 does not. the 0.017 is kind of finicky and definitely feels pressure fitting in.

Resistance across the the + - is very minimal. With my HF multimeter its hard to tell exactly but certainly less than 3 Ohms. The Coil is brandless and has only 3 lines of text on it: "29750" /n "Made in the USA" /n "0202". I could not find that exact P/N but all of my google searches bring up Mercruiser sites. I am not sure if ignorant young me bought that or it came that way. I would like to think I was smart enough to find and check for spark when it first died on me but its been 5+ years since then so not certain anymore.

My coil also has a ballast resistor before the pink and blue lines. It does not have the second spade connector as both leads on the coil are bolt on.

I haven't used a timing light or anything to check spark put purely by attempting a spark against a bolt with either the spark plug or the lead from the coil to the dizzy to a bolt. Nothing, zero, zilch, nada...
 
The service manual specs (above) are for a Bosch 0-221-122-012; I have used a Bosch "blue coil" for many years on my Volvo (all Bosch ignition), sorry don't remember the number, I run an MSD Blaster 2 currently.

the + and - terminals are the primary; really low resistances are hard to measure, any fault in the connection will let it fluctuate wildly- the important thing is that it IS connected (not open), the secondary reading is from the - terminal to the high tension lead to the distributor.

The ballast resistor spec is 0.85 to 0.95 ohms, so hard to measure exactly too, depending on your meter.
 
Wow thanks everyone. I did a few more checks and think i will get a new coil and new condenser. What coil's do you all recommend for a points based system?

The latest checks and updates.

I have a points system with the dizzy on the block. I can't remember which one that is brand wise. I should have a picture here somewhere. Also the gap is pretty much correct. The 0.015 wire feeler fits and the 0.019 does not. the 0.017 is kind of finicky and definitely feels pressure fitting in.

Resistance across the the + - is very minimal. With my HF multimeter its hard to tell exactly but certainly less than 3 Ohms. The Coil is brandless and has only 3 lines of text on it: "29750" /n "Made in the USA" /n "0202". I could not find that exact P/N but all of my google searches bring up Mercruiser sites. I am not sure if ignorant young me bought that or it came that way. I would like to think I was smart enough to find and check for spark when it first died on me but its been 5+ years since then so not certain anymore.

My coil also has a ballast resistor before the pink and blue lines. It does not have the second spade connector as both leads on the coil are bolt on.

I haven't used a timing light or anything to check spark put purely by attempting a spark against a bolt with either the spark plug or the lead from the coil to the dizzy to a bolt. Nothing, zero, zilch, nada...
Also keep in mind that there are coils that have internal ballast resistors (like the stock 74 X1/9 coil). It would be good to identify the coil you are using so that you can determine whether or not to use an external ballast. Probably not the cause of your current issue but using an internal ballast coil with an external ballast would likely result in a less than optimal spark, and using an external ballast coil without a ballast would likely result in a shortened life due to too much power to dissipate.
 
I think I might have found the culprit. The distributor rotor has a radius of 23 but the leads in the cap seem to be 25mm apart. I have the Ducillier 525047A dizzy. Does anyone else have measurements of these or scene this before?
 
There needs to be some gap. The distributor rotor carries the spark from the carbon pin in the center of the cap to the edge of the rotor, it then jumps the gap to the contact along the edge and then down the wire to the plug. 1mm shouldn’t be an issue for a healthy spark.

So, does the cap still have a spring loaded carbon pin in the top? Mine lost its pin in the course of use causing a misfire on an electronic ignition, on a points ignition it may not have enough oomph to jump from the cap to the rotor.

  • Do you get any spark from the coil?
  • Do you have a spark tester? If you don’t have spark from the coil then it certainly isn’t anywhere else.
  • If no spark from the coil then trace back from there, meaning points and condenser.
  • Are the points properly gapped?
  • When was the condenser replaced?
  • What condition is the insulator like for the transition from the inside of the distributor to the exterior, is it allowing the screw to ground out and therefor not breaking the field for the coil?
  • Good continuity of the black wire from the distributor to coil?
  • Is the coil actually getting current from the ignition switch?
  • Have you run a wire directly from the battery to the coil to ensure if the coil is directly fed that it is functioning?
Start there.
 
You are a smart man Karl. I was wondering how actual contact would work, seems it would wear out way too quickly. I simply didnt think about there being a spark across the rotor to cap corners.

  • Do you get any spark from the coil? Nothing coming off the coil to any bolt/stud.
  • Do you have a spark tester? If you don’t have spark from the coil then it certainly isn’t anywhere else. I do not have a tester. I assumed it would be visible jumping to a stud.
  • If no spark from the coil then trace back from there, meaning points and condenser. It still might be the coil or condenser. I need to look up the troubleshoot method. I might need a good multimeter to sample quicker than every second or so. Any other way?
  • Are the points properly gapped? yes 0.015 < gap < 0.17
  • When was the condenser replaced? beats me??? Probably means it wouldnt hurt. :eek: I'll look to troubleshoot that tomorrow and order tomorrow night. Do they go out often? I know its only like $8 so no biggy. I just don't want to wait a week to find out its not the culprit and turn around to have to buy more parts.
  • What condition is the insulator like for the transition from the inside of the distributor to the exterior, is it allowing the screw to ground out and therefor not breaking the field for the coil? Another beats me... I never thought to check that. I'll pull out the dizzy and inspect it closely.
  • Good continuity of the black wire from the distributor to coil? Another thing to check
  • Is the coil actually getting current from the ignition switch? The coil shows 12V from the + and - I believe. If they both ground to the body that makes sense imho. A slight resistance of ~3 across the two +/-.
  • Have you run a wire directly from the battery to the coil to ensure if the coil is directly fed that it is functioning? That would make sense. I'll give it a go. I did measure 12 V from the pink wire in connector in the steering column to ground and also at the pink connector before the ballast. I'm not sure if this would help otherwise.
 
I found the coil currently in my car.
- ACDelco E532
Now if only I could find specs on it and the OEM Bosch unit to compare.
 
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