AJs spark testing

[AJ/FormS]

of the Mopar ECU, and system
When your factory Electronic Ignition Mope fails to fire, here is an on-the-road guide to finding the problem. The only tool you need is a 5 ft length of 14ga insulated wire. If it has alligator clips on each end, so much the better.

First;
>Do yourself a favor and make sure the rotor is spinning in sync with the cranking engine.
> and secondly that it is still under the right towers at the right times
>Next; you have to be sure power is coming out of both sides of the dual ballast resistor, and not just voltage (see #3 below) but actual current; real sparks when you short the output power. I'm not gonna tell you how to prove that, cuz if you burn your car down, I ain't buying you a new one.
So, I'm working from the assumption that you know how to make sparks safely, no where near the carb.

Part I; Does the system pass
the one-spark test?
If the system is alive,the Mopar ECU will shoot a spark every time you cycle the key. To see it, pull the coil wire out of the cap and near-ground it. The better your coil, the greater the gap can be. 1/4 inch is a good start. This bypasses the pick up entirely, and proves both the ECU and the Coil are working.... that is, if you get the spark every time; on then off, will produce the one spark..
>If you don't get the spark, jumper the ECU bare metal case to the battery negative and retest. If spark now, fix your case ground. and retest. If spark now,yur done.
>If still no spark, and the coil-tower is clean and dry , then you will have to prove the ECU and coil.
The coil is easiest, see test #1 below.
The Ecu is by substitution with any other known to be working Ecu.
If still no pass of the one-spark test, then at this point I usually sub in a metal core coil wire, and retest.
If spark now, replace the coilwire, and retest. Still got the one-spark at key cycle? then sub the original ECU back in and retest. Got the one spark?; then plug the coil wire back into the cap, fire it up and and drive away.
But if still no spark IDK, I'm stumped, maybe the pick-up coil is somehow affecting the ECU, or the magnet is broke; sub in a spare.

Part II;
the cranking test
once the ECU passes the one-spark test, move on to the cranking test; this is to prove the magnetic pick up works, which is the last piece of the puzzle.
So with the coilwire still near grounded, commence cranking.
If you get a stream of sparks, yur done.
> but if still no spark, you will have to prove the pick up is good. see test #2. After the pick-up is proven, and the one-spark test is successful; then the three components and all associated wiring is working. So put everything back together and crank it! If it doesn't fire right up and you know the fueling is right, then
The rotor has to be in there, and turning in sync with the cranking engine,lol. and if it is than I refer you back to Test #3.





Test #1
the coil test
testing the coil is easy .The coil should spark with power into the (+), and every time the negative is interrupted. So; disconnect everything on the (-) tower. Take your jumper and clip one end to an insulated whatever thing, then clip the other end to the coil neg.. Pull the coilwire out of the cap and near-ground it again.Turn the key to run. The next part is tricky. Go get that clipped to an insulator alligator clip.
What you are gonna do, is; rapidly make and break that clip to any grounded-back-to-the- battery surface; but it must not rest on any grounded surface. Your clip will essentially behave like a set of points, opening and closing, as it bounces along.
In the shop I use a long flat-bastard file grounded on the engine or battery. In the field I use whatever isn't painted, that I know is made of metal, and is grounded. Then hold the jumper by the wire, leaving 4 to 6 inches dangling. Drag that dangler over the chosen surface, letting it bounce on and off the surface while watching your near-grounded coilwire. You should be seeing a stream of sparks. Don't be tardy with the dragging. There is no condenser so the make and break has to be fairly acute and rapid; a smooth surface will not work, unless you slap it with the clip.Any sparking at all especially multiple ones means it's working.

Test #2
the pick-up test
To make this job easy, I carry a known to be good pick-up in the glovebox and in just a few minutes, I can prove the ECU and Coil are good, or not.
The pick-up is supposed to trigger the ECU every time something made of iron passes across the polepiece sticking up thru the magnet, from any direction, or even stroking it.
So,after plugging the spare pick up in, and with the key in "run", I just stroke the polepiece with something made with iron in it ; Could be; a key or a bobby-pin, a paperclip,a nail, a dime, screwdriver, something on the firewall; whatever.
If I get a spark, then the ECU and coil are working.Now you need to prove the installed pick-up is good.
With no tools; pop the cap off and get it outta the way. Remove the rotor. Turn your crank until you can get to the pole piece of the pick-up without the reluctor being in the way.
With the key in run and the coilwire still near-grounded, just pass your iron whatever tool over the pole-piece, it must remain moving. You can stick it on the magnet, then draw it out, watching for the spark. If the Ecu now sparks, then the components are all working for the one spark test .Hang on;yur not out of the woods yet. Turn the key off, watching for the one spark.
But if it doesn't spark by stroking the pick-up, replace it, and you should be done.

Test #3
voltage versus power
You know; you can bridge your battery posts with a single filament of a 14ga wire and nothing crazy happens; just a lil smoke,sizzle and a melted wire.. But if you happen to lay something substantial across the posts, all hell will break loose.
By the same token, you can light a dash bulb with a tiny flat wire on the back of the PC board, with your 50 pound automotive battery. But it takes big fat cables, still at 12 volts, to crank yur engine over. The difference is how many and how fast, the electrons are moving.
By the same token, you can measure 12 volts going into the ballast resistor, but a single working strand can supply the voltage...... yet not enough electron flow to light a tail-lite bulb. Every electrical device on your car needs both voltage and flow.

 

[xLURKxDOGx]

of the Mopar ECU, and system
When your factory Electronic Ignition Mope fails to fire, here is an on-the-road guide to finding the problem. The only tool you need is a 5 ft length of 14ga insulated wire. If it has alligator clips on each end, so much the better.

First;
>Do yourself a favor and make sure the rotor is spinning in sync with the cranking engine.
> and secondly that it is still under the right towers at the right times
>Next; you have to be sure power is coming out of both sides of the dual ballast resistor, and not just voltage (see #3 below) but actual current; real sparks when you short the output power. I'm not gonna tell you how to prove that, cuz if you burn your car down, I ain't buying you a new one.
So, I'm working from the assumption that you know how to make sparks safely, no where near the carb.

Part I; Does the system pass
the one-spark test?
If the system is alive,the Mopar ECU will shoot a spark every time you cycle the key. To see it, pull the coil wire out of the cap and near-ground it. The better your coil, the greater the gap can be. 1/4 inch is a good start. This bypasses the pick up entirely, and proves both the ECU and the Coil are working.... that is, if you get the spark every time; on then off, will produce the one spark..
>If you don't get the spark, jumper the ECU bare metal case to the battery negative and retest. If spark now, fix your case ground. and retest. If spark now,yur done.
>If still no spark, and the coil-tower is clean and dry , then you will have to prove the ECU and coil.
The coil is easiest, see test #1 below.
The Ecu is by substitution with any other known to be working Ecu.
If still no pass of the one-spark test, then at this point I usually sub in a metal core coil wire, and retest.
If spark now, replace the coilwire, and retest. Still got the one-spark at key cycle? then sub the original ECU back in and retest. Got the one spark?; then plug the coil wire back into the cap, fire it up and and drive away.
But if still no spark IDK, I'm stumped, maybe the pick-up coil is somehow affecting the ECU, or the magnet is broke; sub in a spare.

Part II;
the cranking test
once the ECU passes the one-spark test, move on to the cranking test; this is to prove the magnetic pick up works, which is the last piece of the puzzle.
So with the coilwire still near grounded, commence cranking.
If you get a stream of sparks, yur done.
> but if still no spark, you will have to prove the pick up is good. see test #2. After the pick-up is proven, and the one-spark test is successful; then the three components and all associated wiring is working. So put everything back together and crank it! If it doesn't fire right up and you know the fueling is right, then
The rotor has to be in there, and turning in sync with the cranking engine,lol. and if it is than I refer you back to Test #3.





Test #1
the coil test
testing the coil is easy .The coil should spark with power into the (+), and every time the negative is interrupted. So; disconnect everything on the (-) tower. Take your jumper and clip one end to an insulated whatever thing, then clip the other end to the coil neg.. Pull the coilwire out of the cap and near-ground it again.Turn the key to run. The next part is tricky. Go get that clipped to an insulator alligator clip.
What you are gonna do, is; rapidly make and break that clip to any grounded-back-to-the- battery surface; but it must not rest on any grounded surface. Your clip will essentially behave like a set of points, opening and closing, as it bounces along.
In the shop I use a long flat-bastard file grounded on the engine or battery. In the field I use whatever isn't painted, that I know is made of metal, and is grounded. Then hold the jumper by the wire, leaving 4 to 6 inches dangling. Drag that danger over the chosen surface, letting it bounce on and off the surface while watching your near-grounded coilwire. You should be seeing a stream of sparks. Don't be tardy with the dragging. There is no condenser so the make and break has to be fairly acute and rapid; a smooth surface will not work, unless you slap it with the clip.Any sparking at all especially multiple ones means it's working.

Test #2
the pick-up test
To make this job easy, I carry a known to be good pick-up in the glovebox and in just a few minutes, I can prove the ECU and Coil are good, or not.
The pick-up is supposed to trigger the ECU every time something made of iron passes across the polepiece sticking up thru the magnet, from any direction, or even stroking it.
So,after plugging the spare pick up in, and with the key in "run", I just stroke the polepiece with something made with iron in it ; Could be; a key or a bobby-pin, a paperclip,a nail, a dime, screwdriver, something on the firewall; whatever.
If I get a spark, then the ECU and coil are working.Now you need to prove the installed pick-up is good.
With no tools; pop the cap off and get it outta the way. Remove the rotor. Turn your crank until you can get to the pole piece of the pick-up without the reluctor being in the way.
With the key in run and the coilwire still near-grounded, just pass your iron whatever tool over the pole-piece, it must remain moving. You can stick it on the magnet, then draw it out, watching for the spark. If the Ecu now sparks, then the components are all working for the one spark test .Hang on;yur not out of the woods yet. Turn the key off, watching for the one spark.
But if it doesn't spark by stroking the pick-up, replace it, and you should be done.

Test #3
voltage versus power
You know you can bridge your battery posts with a single filament of a 14ga wire and nothing crazy happens. But if you happen to lay something substantial across the posts, all hell will break loose.
By the same token, you can light a dash bulb with a tiny flat wire on the back of the PC board, with your 50 pound automotive battery. But it takes big fat cables, still at 12 volts, to crank yur engine over. The difference is how many and how fast, the electrons are moving.
By the same token, you can measure 12 volts going into the ballast resistor, but a single working strand can supply the voltage...... yet not enough electron flow to light a signal bulb. Every electrical device on your car needs both voltage and flow.

Thanks for posting!!! Sticky bound.

Jake

 

[halifaxhops]

Great needs to go into the how to area!!!