maxprivate

iTrader: (12)

I have a CEL for Ignition signal circuit ( code 0102 ) and I been doing some research on how to test the coil packs. I found a thread explaining to use a volt meter to test resistance on each etc. But I have also read if they test out to be good they can still be bad because under high heat and load the bad coil pack or packs can act up under load.

Im stumped now because my mechanic is telling me to change all 6 which will run about 600 bucks for OEM ones ( not going with generic ones on ebay) he did a test on them using his OBD scanner which basically mimics unplugging each harness from the coil pack and you can feel the idle change and buckle once each coil pack is affected. So each coil pack changed the idle and made the car buckle,with out the car throwing a specific code for which cylinder is misfiring it is hard to tell which is bad.

He told me I can start with the back 3 by the fire wall. Still it just doesn't seem logical to replace them all if its maybe 1 or 2 causing the problem. Any info or experience you guys have regarding coil packs will help. I know its a misfire because the car is running like crap and has a weak idle I had this same problem when I left one coil pack unplugeed by mistake after changing the spark plugs and the car idled the same way its acting right now... spark plugs are new.

njmaxseltd

iTrader: (19)

If your getting the ignition signal circuit, then the ECU is detecting the error on the low side of the coil This should be easily detected with an ohm meter. Follow the instructions on the thread you read. If the readings are off, replace the coil.

The ECU really has no way of detecting an error on the high side of the coil. It's not electrically connected to the ECU. A misfire on the high (spark) side is detected by the cam and crank sensor. The engine speed or gallop caused by the misfire is picked up in the RPM signal and reported as a misfire. The engine timing from both sensors can help accurately determine which cylinder is at fault.

The TDC codes an ohm meter & spark tester are your best friends when troubleshooting ignition related issues.

maxprivate

iTrader: (12)

I will test them and see if any are way off according to the others. Makes no sense to replace good working parts and waste money. Do you know if the Haynes explains how to test them? I saw a couple posts on how to ohm them out but both were different and unclear.

DennisMik

iTrader: (2)

Each ignition coil has a transistor built into it. The transistor is the on/off switch that controls current flow through the primary side of the ignition coil. The transistor gets it's on/off command from the ECU.

Measuring resistance (ohms) is, for the most part, measuring the transistor.

I took these readings on my 1997 Maxima with 150K miles. Readings were taken for reference - no known problems.

All the coils are factory originals and all the coils measured very close to each other. The numbers recorded are an average.

There are 3 connections on the coil pack:
Pin 1 - red wire on every coil pack, 12 volts
Pin 2 - black wire on every coil pack, chassis ground
Pin 3 - different color on each coil pack, trigger from ECU

measuring between Pin 1 and Pin 2 connections:
reads 1.6 K ohms (polarity doesn't matter).

measuring between the Pin 2 and Pin 3 connections:
reads 7.1 M ohms (polarity doesn't matter).

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

pmohr

iTrader: (26)

All that power balance test does is to see which cylinders aren't contributing, it can't tell you if it's a coil, injector, compression, timing, etc issue that is keeping that cylinder from properly making power.

Like you said, if you test a coil with a DMM and it tests bad, it's bad. However if it tests good, it can still be bad. All you can test is the transistor and primary coil, and then only when it's not under load. The only foolproof way I know of to test the coils is a current ramp, for which you'll need an oscilloscope (or at least a GMM) and the knowledge to interpret the results.

A decent shop should have at least one tech with a scope and current clamp that knows how to use it, and it shouldn't be more than a half hour labor for the results.

maxprivate

iTrader: (12)

Thanks for the reply guys.. I know have something I can at least work with rather than just replacing all 6 coils.

maxprivate

iTrader: (12)

I tested each coil today as per the Chilton manual. Its says check resistance on each coil between terminal 1 and 2. Im assuming the + symbol on the coil is 1 and G terminal is 2 ( my coil packs have + G IB labled on them for front and rear coils ) I get 348k roughly on all coil packs bet 1 and 2 on the coil. Chilton says I should get 0.8ohms

Then with + lead from Volt meter on terminal 1 or + sign on coil to terminal G or 2 ( We will call G terminal 2 ) I get infinity or no measurable resistance on all coil packs.

Negetive lead from volt meter to + Sign on coil ( terminal 1 ) and positive from volt meter on Terminal G ( terminal 2 we are calling G on coil ) I read roughly in the 350k range on all coils. These readings I am getting are not matching anything according to other reaserched test reading I have found by other members.

Could all 6 of my coil packs be bad? Doesnt make sense..

Could it be bad injectors? Im using 370 cc injectors and Im Supercharged.. probably makes no difference though.

schmellyfart

iTrader: (46)

Don't you have an EU installed?

maxprivate

iTrader: (12)

Yes I do. Why do you ask?

schmellyfart

iTrader: (46)

Not sure if its a typo, but I just noticed you typed 0102 which is actually a MAF code.

The ignition circuit fault (0201) is a common issue with the EU in our cars. I got the same code after I installed my EU. All it takes to fix is to install 330 ohm resistors on each of the ignition lines in the emanage.

maxprivate

iTrader: (12)

Yes its a typo then, the I got the ignition signal circuit code. I actually do have the resistors soldered into the EU. I'll double check to make sure nothing came loose which I doubt.. But Im sure that wouldnt make the car run rich on fuel and idle the way it is.

I wish the ECU would throw a misfire code.. All my coil packs are testing out with identical reading as per the testing procedures I found searching so I cant determine the odd one out.

I refuse to spend 600 bucks to replace them all, not fond of guess work especially when in involves that much money and not sure if the coils are the problem.

schmellyfart

iTrader: (46)

I'd double check the ignition line wiring on your EU, seems like there is a loose connection on one of your ignition lines.

If its feasible, (I don't know how your EU is wired in) I would disconnect the ignition lines from the EU and see if the problem remains,

maxprivate

iTrader: (12)

I don't have it soldered in, I just used plug in type male and female connectors and I had loose wires trying to tuck all the wires back in place but I was able to fix them. Im gonna solder everything eventually..

I would like any feedback from anyone on how to get a conclusive test ( if any ) to determine if coil pack are working properly. http://forums.maxima.org/4th-generat...ultimeter.html

used the linked method, Chilton method which my readings where no where near 0.8 ohms as it says. I was getting 1.4 ohms on each coil pack all reading were more or less similar. And 1 other method I found on the org and found no odd reading on any coils.. all readings were similar.

+ lead from meter to + on coil and neg lead from meter to G terminal on coil was getting infinity or no measurable resistance on all 6 coil packs.

neg ( - ) lead from meter to + on coil and + from meter to G terminal on coil I was reading roughly 350k ohm range on each coil. Im starting to think my problem isnt the coils at all.

I have a bad O2 sensor I need to replace and I will do that this week. I wonder if a bad O2 will affect long term and short term fuel numbers coming from the ECU. hmm I'll see if it runs any better after replacing the O2 sensor.