By Gary Goms. I encourage you to try this on more that one vehicle. You also want to make sure that the current ramp is nice and smooth. For this example we’re working on a 2013 Ford Fusion as it uses what’s called a multi-strike ignition, which is trying to dissipate all of the extra energy in the coil by firing multiple times. Send e-mail. 1 millijoule = 10-3 J. Ignition coils of the latest generation have spark energies of up to 120 mJ. Simply plug the coils in, and you'll be able to play all day.Application. Spark fires at this point (ignition coil stops charging and all of the energy is released into the coil secondary which is connected to the spark plug). 5 portrays the current to an indi-vidual plug-mounted ignition coil. Current Ramp Testing Ignition Coils with an Oscilloscope. Current Ramping 11/07/2012 by Carlos M As Gary Goms says in his article, "Current ramping is certainly not new technology, but it continues to be a valuable method of diagnosing primary ignition and fuel pump problems." Bad or faulty coils can cause stalling, backfiring, strange noise coming from the engine or low engine power. Usually the fall time is in the 3- to 4-microsecond range. base, revealing a healthy current ramp. This is a pretty simple and unobtrusive test you can run to make your life easier when it comes to ignition coil diagnosis. Instantaneously the spark jumps the spark plug gap. For comparison, Fig. These Ford Racing three valve Coil On Plugs are designed as a direct fit replacement for the 2008 to 2010 4.6L 3V GT Mustangs with 12mm spark plugs. This is transformed on the secondary side of the coil and converted in the ratio of "number of secondary windings to primary windings". At the time of ignition, the coil current is switched off by the ignition output stage. The low-tension (LT) signal switches between zero volts and about 5 volts. And it’s important to make sure that the pattern is straight – anything with a curve would show another issue with the coil. Ignition current ramp was created by Charles Acosta In the diagram if I connect an amp probe where the red circle is drawn. Ignition Coil Current Ramp Test- Diagnostic Quick Tips | Snap-on Training Solutions® - YouTube Having a hard time figuring out whether or not an ignition coil is bad? Coils can be tested with an ohmmeter, although they are very durable and rarely go bad. 6 shows the same coil under a If you have any of them that are out of the ordinary, then you want to do a little more investigation. The ignition coil current reaches about 9 Amps at its peak. 4. Capture a valid Current Ramp lab scope pattern of an Ignition Coil. Either 12V across a 3-ohm primary coil or 6-9V across 1.5 ohms in a ballast coil. 19. If in doubt, compare amperage draw with a similar known-good system. Once you’re recording, start the vehicle and generate some data for a few seconds before pausing the recording and switching off the vehicle. A normal system should have the coils all be fairly equal. At this point the current is maintained for a brief period of time and then released at the point of ignition. Fig. 19 on page 54 is the trace of a distributor-mounted ignition coil from a Honda Accord. Engines with late style 12MM spark plugs can be identified by coil engineering number Primary coil current ramp showing a false short. In-store price may vary from online price. We will cover the physics that govern some of the ignition coil behavior to gain a deeper understanding and provide a more reliable diagnostic method that is based on the physical laws. These ignition coils are designed to be a direct fit for your truck, so installing them should only take about 1 hour. NATEF #292, 402 . There are many different ways to diagnose ignition problems on a vehicle using a Snap-on® lab scope. You want to make sure that the current ramp is nice and smooth. After the primary coil winding amperage draw stops, the primary coil winding's magnetic field collapses and then the COP's secondary winding creates the high voltage to force the burn voltage to jump the spark plug gap, to the plug's ground terminal. If a coil is drawing excessive … The ignition coil driver module of the present invention includes a control integrated circuit, formed of a low voltage semiconductor material, and a high current load driver integrated circuit, formed of a high voltage integrated circuit, housed within a common package. #1) READ-STUDY Using the Low Amp Probe for Coils on How to Current Ramp Ignition Coils and Fuel Injectors, #2) COMPLETE the QUIZ  (score 90% or better for full credit)Ask questions if you are not sure about the answers to this quiz! I had done some work to my car recently, which is a 99 chevy metro. One way to work your way to a solution is to run what’s called a Coil Current Ramp Test, which operates with the aid of the diagnostic software on Snap-on platforms. Using a low-amperage current probe to measure the current “ramp” through the primary ignition circuit is perhaps the most definitive method of determining the electrical integrity of the coil and the quality of the grounds and primary windings. An important performance criterion for ignition coils is their spark energy. Remember that most ignition coils shouldn’t draw more than eight amps. The ignition coil is basically a transformer, which steps up the 12-volt (low voltage) from the battery, to the high voltage required to jump a spark plug gap. Ignition coil waveforms can be monitored using a cheap current clamp on Fuse #2 in the under-dash panel. After the primary coil winding amperage draw stops, the primary coil winding's magnetic field collapses and then the COP's secondary winding creates the high voltage to force the burn voltage to jump the spark plug gap, to the plug's ground terminal. The instantaneously collapsing magnetic field generates a high induction voltage in the primary winding. You might be facing a faulty ignition coil or something similar but you’re having a difficult time trying to get to the bottom of things. Many defective ignition coils, for example, will pass a resistance test but fail a current ramp test. The capture was made at idle and clearly shows a flat top 2.6mS after turn-on, a characteristic of current limiting going into effect. Be ready to discuss:               1-How to set up and zero the low amp probe,               2-How to set up the Filter - Trigger - Time and Volts (or Amps)                    to capture the most detail for ONE ON-OFF cycle of the Fuel Injector               3-How to find ONE wire to display ALL 4 - 6 - or 8 injector firing events                4-How many amps the coil is using               5-How many milliseconds for one ON-OFF cycle                6-Why current should display a ramp up to maximum current               7-How low fuel injector resistance (short) will appear on the screen               8-How the timing of the Pintle Bump can show a defective fuel injector               9-Importance of comparing Pintle Bump of one injector to all injectors                      (some styles of fuel injectors do not show a pintle bump), Instructor Signature Fuel Injector  ____________________, Graphical version of Phil Krolick's Website: A low amp probe ( COP ) assembly the moment the current ramp lab scope pattern of an coil... 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