Hey Buds...

Thought this video would be useful for those who are trying to determine whether their COIL pak(s) are shot.

FIRST part of the video is BS old school way of testing. SECOND half of video he goes into using "multi-meter" testor to check whether or not coil is working. I'm not sure if the 5th gen has internal or external resistors. Nor what the test using Ohm should read. Video suggest that if there is any kinda of reading, the coil is good.


Comments, constructive input?

~M

 

Oh man, this brings back bad memories since my 2000 seemed to love going through coils and getting the dreaded P1320. I haven't had any problems with my last set of OEM coils (knock on wood).

The multimeter method will not work all of the time, but it does work occasionally. Sometimes the readings would be fine, but the coil was still bad.

Here's another video by the same guy that discusses testing the condenser towards the end of the video:

 

I have seen some of his other videos and I'm not that impressed. If he himself really knows the subject, he is not able to get the information across to others.

To clarify something about that video - it was done on a 4th gen. The ignition coils are different from the 5th gen in that the pin numbers are not the same. Pins 1 and 3 are reversed between the two generations. In the video, he said to measure resistance between pins 1 & 2 (4th gen) but this translates to pins 3 & 2 for a 5th gen.

Inside the ignition coil are 2 things: a transformer and a transistor. The transformer is the actual "coil" that increases the voltage so a spark can be created. The transistor is the on/off switch for electrical current through the coil.

Measuring resistance across pins 1 & 2 (4th gen) or pins 3 & 2 (5th gen) is measuring across the transistor to see if it is allowing electrical current to pass through it. But you need to understand a little bit about transistors. Transistors are made up from diodes. Diodes are things that allow electrical current to flow in only one direction.

You also need to know a little bit about an ohmmeter. An ohmmeter works by sending electrical current from a battery inside it into the item you are testing and measuring how much of that electrical current come back. The key word in the previous sentence is BATTERY. A battery has a positive terminal and a negative terminal. Electrical current flows only one way from the battery, out of the positive terminal and returns to the negative terminal. That's why the ohmmeter has different color leads (wires). The black wire connects to the negative side of the battery and the colored lead, usually red, connects to the positive side of the battery.

So when you measure the resistance of a transistor or a diode, it definitely makes a difference as to which ohmmeter lead goes to which transistor/diode lead. In the case of the 5th gen ignition coil, the black meter lead on pin 2 and the red meter lead on pin 3 should give you a reading of infinity (no connection). If you reverse the meter leads, you should get a reading of about 7.7 mega ohms.

When measuring transistors/diodes, you should ALWAYS measure it with the meter leads in both directions. You want to make sure the transistor/diode conducts when it should and turns off when it should.

Here are the ohmmeter checks for a Nissan factory 5th gen ignition coil.

There are 3 connections:
Pin 1 different color on each coil pack
Pin 2 black wire on every coil pack
Pin 3 red wire on every coil pack

measuring between Pin 3 and Pin 2 connections:
positive lead on Pin 3 reads open (or infinity)
positive lead on Pin 2 reads 7.7 mega ohms

measuring between the Pin 2 and Pin 1 connections:
reads 1.5 kilohms (polarity doesn't matter).

measuring between Pin 3 and Pin 1 connections:
positive lead on Pin 3 reads open (or infinity)
positive lead on Pin 1 reads 7.7 mega ohms

 

To answer the op's question about knowing which scale to set the ohmmeter on, you have to know what the resistance reading should be, otherwise you won't have any idea if the reading you get is correct or not.

To measure an unknown resistance value, you set the meter to the lowest scale. If the meter shows infinity (maximum resistance) then change the meter scale to the next higher scale. Keep going to a higher scale until you get a reading. You could also start at the highest scale. If the resistance is too low for that scale, the meter will read zero ohms or a short, so you switch to a lower scale until you get a reading. With a digital meter, it doesn't matter which way you do it, it won't hurt the meter. But if your meter is the needle type, then you should start on the high scale and switch down.

If you are going to buy a multi meter, spend another couple of dollars more for a model that has the auto-ranging feature. There is only one setting for volts, one for ohms. For $25 you can get a fairly decent auto-ranging meter. You can also get them for less, but buy decent tools, don't buy garbage.

 

Thanks Denis,

HE states that he doesn't know what the ohm reading should be....only that "if there is one, then the coil is probably ok."

???

Not sure if that logic works in this case or not? TO ME, it sounds correct. A coil either works or it doesn't. AM I WRONG?

~M

 

You will get yourself in trouble eventually if you believe that. You really do need to know the specifications to be able to say a part is good or not.

That's kind of like saying that if the car starts, you have enough gas to go 300 miles. While there may be some gas in the tank, the fact that the car started does not mean that there is enough gas for a long trip. You have to use a test device called a fuel gauge to see how much gas is in the tank.

Every part has a "range" for the conditions that allow it to do its job. A bolt has torque specs - too low and it will loosen up on you. Too high and the bolt may snap. Your tire has a range for the air pressure. Too low and the tire can't support the weight and the rim may end up bent when when you hit a pot hole. Too high and the tire may explode.

Electrical devices like a transistor are the same way. The amount of resistance the transistor has determines the amount of electrical current that will flow through the device and its wires. The less the resistance, the more electrical current will flow. Too little resistance (a short circuit) and you blow fuses or burn up wires. Too much resistance and not enough electrical current will flow. In the case of an ignition coil, not enough electrical current will give you a weak spark or no spark.

 

Thanks Dennis for the information. With all this said does anyone know the specs or is there a spec for these coils. I just measured bank 2 coils and am getting consistent numbers just more elevated.

1.485-1.500k ohms and 11M ohms and it slowly bleeds down to 10.6 or so. Like I said these are all bank 2 and consistent so I'm thinking I'm in good shape.

 

If all the coils measure the same, they are probably OK. It is highly unlikely that you would have 3 bad coils that measure the same. Also, the resistance of bank 1 coils and bank 2 coils should be the same.

As for the reading changing as you were measuring it, that means that the internal components in the coil were "charging up". There is a transformer in the coil and when current flows through a coil, it creates a magnetic field. Until the magnetic field has fully developed, the reading on your meter will be changing.

The resistance values I gave you were for 2000 coils. If Nissan changed the spec, that could account for this.