240 How do I MANUALLY create a spark?

[ZVOLV]

... I suspect that is how I would do it. Would I die?

I urge you, and others, to go turn the key on, and then jumper coil negative to ground and see if they can get a spark. I couldn't get it to work consistently. I got it to work exactly ONE time. I consistently got arcing when I touched the jumper wire to the coil negative or battery negative, but that was it.

Post back with results.

EDIT-I got off my butt and did some tests.

Crank sensor signal wire tapping to ground. SPARK!!!

8 Second Video:

<iframe width="560" height="315" src="https://www.youtube.com/embed/i0kW1REDk3Y" frameborder="0" allowfullscreen></iframe>


Jumping coil negative to ground. ARRRRRRC!!!!

6 Second Video:

<iframe width="420" height="315" src="https://www.youtube.com/embed/uTonM3lE66g" frameborder="0" allowfullscreen></iframe>

 

[745 TurboGreasel]

So
What causes arcing in the primary?

 

[cwdodson88]

I urge you, and others, to go turn the key on, and then jumper coil negative to ground and see if they can get a spark. I couldn't get it to work consistently. I got it to work exactly ONE time. I consistently got arcing when I touched the jumper wire to the coil negative or battery negative, but that was it.

Post back with results.

EDIT-I got off my butt and did some tests.

Jumping coil negative to ground. ARRRRRRC!!!!

try charging the primary circuit instead of just waving the wire around. go back to a points system here, neg lead attaches to the points, yeah, so when points are touching, coil charges, right, then the points open, spark at the plug happens, this happens because the charge in the coil has no where to go except the spark plug... so try your tapping the neg lead to the fender again but put your rubber gloves on and hold the neg lead down then watch when you release it.

 

[ZVOLV]

So
What causes arcing in the primary?

Still waiting for your answer from post #7....

Tell me how you would do it or show me a video of it working.

try charging the primary circuit... put your rubber gloves on and hold the neg lead down then watch when you release it.

AGAIN, no amount of poking, holding/releasing has worked. No rubber used.

 

[bobxyz]

I can't tell from your video, but where is the test lamp inserted? Did you rotate the distributor at all between shooting the 2 videos?

I'm wondering if you put the test lamp in the coil to disti cable, but that the distributor rotor isn't lined up with a plug tower on the disti cap. If the spark is still going through the distributor, the rotor needs to be close to a plug tower connector so that it can jump across. If the rotor is positioned between plug towers, the distance may be too far and the spark dissipates instead of jumping. Make sure your disti is aligned to TDC and try tapping the coil wire to ground again.

 

[ZVOLV]

Coil wire is unplugged from dist and inserted into a spark tester.

In the first video I didn't show the rhythm, but I was simply tapping a jumper wire from the crank sensor signal to the battery ground in the crank sensor video. Sometimes I could get lucky and get a spark quickly. You also may have heard that the fuel pump and IAC valve powered up too! Valid test. Success! Unless I short out the computer or something. Any objections to my test? If so, explain why.

In the second video I am simply poking a wire that is attached to battery ground to the coil negative. Key on. No spark like you guys are saying will happen. I even tried having the wire connected to ground BEFORE turning the key on, then pulling the ground away. NO SPARK. AGAIN, no amount of tapping at different frequencies, holding for short periods, etc will make the coil spark.

I think the people telling me how it works understand that the computer grounds/ungrounds the coil to create spark, but in PRACTICE, just going in there with a jumper wire doesn't work.

 

[bobxyz]

I know what's going on -- for grounding&releasing the coil primary directly to work, you need a condenser in the circuit to allow the primary to discharge, and magnetic field to collapse, rapidly. The rapid collapse generates the high-voltage on the secondary. For the old points distributors, the condenser is a ~1/2" x 1" metal can usually screwed to the outside of the distributor. Without this, or if you had a bad condenser on an old points distributor, you'll get a weak to no spark and will have arcing on your points/wire.

Modern ignition modules provide a different discharge path for the primary, but I'm not sure it works correctly and without damage, if you ground the coil with the module connected.

For testing the coil, I'd recommend:
- disconnect all the wires and measure resistances
- mark the distributor position, loosen clamp, and rotate near tdc to get a spark

I'm not sure if grounding the the sensor out of the distributor is safe for all varieties of Volvo ignitions - maybe someone from a Volvo shop can comment on how they check spark.

 

[cwdodson88]

I know what's going on -- for grounding&releasing the coil primary directly to work, you need a condenser in the circuit to allow the primary to discharge, and magnetic field to collapse, rapidly. The rapid collapse generates the high-voltage on the secondary. For the old points distributors, the condenser is a ~1/2" x 1" metal can usually screwed to the outside of the distributor. Without this, or if you had a bad condenser on an old points distributor, you'll get a weak to no spark and will have arcing on your points/wire.

Modern ignition modules provide a different discharge path for the primary, but I'm not sure it works correctly and without damage, if you ground the coil with the module connected.

For testing the coil, I'd recommend:
- disconnect all the wires and measure resistances
- mark the distributor position, loosen clamp, and rotate near tdc to get a spark

I'm not sure if grounding the the sensor out of the distributor is safe for all varieties of Volvo ignitions - maybe someone from a Volvo shop can comment on how they check spark.

I completely forgot about the condenser. My bad.

As for testing, IF you're trying to independently test the coil and not any other components, fire the parts cannon on a 2$ condenser and use the points method.

By jumping the signal at the CPS to trick the computer into thinking its go time, you're not just testing the coil, you've got the ignition computer, wiring harness, etc all needing to be functional for the test to work.

 

[ZVOLV]

How do I make a coil on plug fire?

 

[Chris Wilson]

Depends if it has an inbuilt amplifier or uses an external one. what is the make make and model and the number of connector contacts? Without an igniter it can be treated like a normal coil. with an igniter built in it needs the correct voltage trigger pulse to the igniter input pin.

 

[ZVOLV]

Depends if it has an inbuilt amplifier or uses an external one. what is the make make and model and the number of connector contacts? Without an igniter it can be treated like a normal coil. with an igniter built in it needs the correct voltage trigger pulse to the igniter input pin.

I have a VW 4 pin and a Ford 2 pin on the shelf.

 

[cwdodson88]

Ford are going to be just like a standard coil (no igniter) the be ones need a 5v trigger.

 

[Chris Wilson]

Ford are going to be just like a standard coil (no igniter) the be ones need a 5v trigger.

And a 12 V feed for the primaries of course!

Just to expand 99% of modern ecu's have a very accurate 5 volt positive reference supply that is output from several pins and goes to things like the ECU water temp sensor, the throttle position sensor, the MAP sensor, blah blah. The output of these sensors varies from very little volts to 5V depending on their temp, position, port pressure, whatever. With coil on plug coils with inbuilt igniters they need the 12 volts to run the coil itself, and a pulsed 5V reference from the ECU, which is a modified signal from the crank and camshaft position sensors, modified as in altered by the ECU's map, and other sensors.

If you go to the Australian MOTEC site they used to have a link to some excellent webinars on ecu control and all the various sensors and modules. http://www.motec.com.au

It's probably gone to YouTube or Facebook these days...

 

[ZVOLV]

"Coils need the CORRECT PULSE-WIDTH or they won't respond properly. If the pulse width is too wide, the coil will over-saturate and not build the strong magnetic field needed to produce a nice spark":

http://www.autodiagnosticsandpublishing.com/ignition_coil_pulser_tester.html

 

[5ft24]

first, make the gap smaller... the condensor used on a points system damps oscillations in the primary when the points open, and maximizes output from the secondary (spark) grounding and ungrounding the wire will get small, weak sparks from the secondary, but it will spark. just went to my 90 740T and tried it... small, weak ass sparks.
And to test if the crank sensor is working, watch the tach as you crank the engine over... if the tach moves, the Crank sensor is working.

 

[ZVOLV]

if the tach moves, the Crank sensor is working.

Incorrect. On many models, tach only gets power after engine has started. Power is pulled during cranking.

Ford are going to be just like a standard coil.

With a two wire COP, or an old style standard distributor system ignition coil. I simply have to GROUND the negative for a specific dwell period for optimal spark and not just a little queefe of a spark. What does this signal look like and how would I create it? I like the idea of a spare points style dist in a drill as a cheap way to draw the coil to ground with the proper dwell for proper spark.

(VW) ones need a 5v trigger.

What does this 5v trigger look like? How could I simulate it?

 

[cwdodson88]

With a two wire COP, or an old style standard distributor system ignition coil. I simply have to GROUND the negative for a specific dwell period for optimal spark and not just a little queefe of a spark. What does this signal look like and how would I create it? I like the idea of a spare points style dist in a drill as a cheap way to draw the coil to ground with the proper dwell for proper spark.




What does this 5v trigger look like? How could I simulate it?

1- that sounds about right, but the magnetic field created by the primary needs to fall within a certain spec to achieve the nice blue spark that we like to see. I tested the tapping coil neg to ground (at night with lights out) and was able to get a spark, it was weak, but there. The video wouldnt capture on my cell, I might try it again this weekend and see if I can get it to show on video.

2- Basically its just 5v with enough current to power an led.

 

[ZVOLV]

1- the magnetic field created by the primary needs to fall within a "certain spec" to achieve the nice blue spark that we like to see. I tested the tapping coil neg to ground (at night with lights out) and was able to get a spark, it was weak, but there. The video wouldnt capture on my cell, I might try it again this weekend and see if I can get it to show on video.

2- Basically its just 5v with enough current to power an led.

Hey thanks for posting back. Glad to hear a couple members actually did their own tests and figured out that you CANNOT just tap negative to ground. I honestly thought the same thing , but I was wrong. I even wrote it in my "No Start" article and when I tried it, it didn't work.

Again, the purpose of this thread is to create tests procedures and to create a further understanding of how old and new ignition systems work.

Dwell is controlled by the ignition system to control the AMPS in the primary for optimal spark. This can vary by battery voltage for example. Cold mornings, etc. Did I say that right? Ha. I need more practice. Gotta go to work right now.



The SIGNAL for a coil with ignitior/amplifier built into it a square wave. It POWERS the coil signal wire for a specific period of time. See, the peak of the square wave is the computer triggering the coil. The TIME that the peak is there (milliseconds. X axis) is the TIME/Dwell that the ECU is telling the coil to charge up for.

Highly caffeinated and gotta go. Correct me if I am wrong!