hey my car has rough idle and slightly dimming lights.... i checked the alternator and am going to replace my spark plugs soon... but how do i check if the coilpacks are good or not just to be sure?? thanx

 

bump...... anyone have an idea?

 

hmm battery? grounds?

go in a dark room and see if ur getting spark in each one i guess..

 

You can check the coils with an ohmmeter to determine whether or not they are firing and to see if the internal resistance is too high to create a hot spark. I'll check a brand new coil when I go to work tomorrow to see what the resistance is supposed to be

 

aite i appreciate it 99maxxx cuz i am going to get an ohmmeter tmrw but i need a guideline by which to go by to see if mine are within spec or not... also where are the coilpacks exactly, so that it saves me a trip to the shop thanx

 

Well, for the three in the front you have to remove the little plastic cover that goes in the middle of the valve cover. It's held on by 4 allen head screws. Once you get that off you'll see the coilpacks. Each one is held down by 2 10mm bolts.

The rear coilpacks actually go through the openings in the top of the intake. If you look at the back of the engine, you will see that the other coils actually mount directly to the intake. You can remove them the same way...2 10 mm bolts. Hope this helps

 

aite yea i see what ur saying, if u could just let me know what the resistance should be thanx

 

That would be great. I checked all of mine last night. The Chilton's and Hayes manuals have different ways of checking and my readings vs. Chilton's for the resistance are significantly different. The terminalss read across L_R >>>>>> I B G+. My reading on the I B were 1.68 ohms. Hayes test the packs on the B G+ terminals and do not specify a value. I was reading 20.02 ohms. Depending how you hook the leads up on the Hayes method (polarity on the leads), you will read infinite one way or a value on the second. They have you hook up the leads both ways. Hope this helps for a start. I am waiting to see what new ones read.

 

Well, it was kinda weird actually.....I tested the new coil while I was at work yesterday and all terminals in all configurations read infinity except for IB - G which read 1556 ohms. Now correct me if I am wrong, but an ohmmeter is not affected by polarity, right? I tried all the terminals both ways, but I don't believe it matters.

 

I would think polarity would not be an issue, but it this case it did make a difference as described in the Haynes manual. In their write up, they indicated initially putting the positive lead on the G+ and the negative on the middle one (pics in the manual also). Then take a reading hooking them up just the opposite. That's how I obtained my readings. Looking at my meter, the polarity is marked on the meter. Never ran into that before for resistance readings. And of course, then we have the Chilton's way. I believe they stated the reading on the terminals I and B should be .08 (or was it .8 --- SORRY, I'm at work and don't have my manual with). I read 1.6. Anybody else want to test theirs and give some more numbers? I believe there was another thread on this somewhere, but I can't locate it. I believe it had a procedure and numbers. All my coils were relatively close in values.

 

I just did a very intensive study on Nissan coil packs, and not by choice. I had idle speed misses, check engine light flashes on hard acceleration, general acceleration is basically bad and bad mileage on my 99 Max.

After much cleaning and sensor checking I bought all new coil packs and started to replace them one per week. The first cylinder I replaced (#1) cleared the idle speed problem and the check engine light problem, what a difference. Now I wanted to document how to tell a good coil from a bad one.

The ohm meter readings were not different between the good and the bad coil. How can that be?. Well I took a hammer and a chisel and did some surgery on the bad coil. I found a small circuit board in the coil. The coils are more than pure coils, primary and secondary windings, the service manual shows a transistor and diode circuit so I wasn’t real surprised. But this means that testing the coils with an ohm meter is highly unlikely.

Back to my testing, #2, #3 no major improvements. #4 acceleration improvement beyond belief, its like a new car. #5,#6 no major improvement.

Now what does this mean to the DIY guy that tunes up his car. To me it means that the coil packs are a maintenance item like any other item that should be replaced every x number of miles or at least something to worry about. I think the last and only coil I every replace on a car was a 1966 Ford so it’s not something I expected to fail.

Swapping seems to be the only real method to check them out and for the 99 Max that means two different coils, the front is different from the back. Yes I saved the good ones for such an application.

I still wonder if it’s the coil packs that go bad because of use or the environment they are living in. Its got to be real hot done there.

That’s my take on the coil issue. Hope it helps others.

 

http://forums.maxima.org/showthread....=coilpacks+fsm

 

thanks for the link. guess i'll be saving up as well. but just wanted to see if anyone else had this problem.

whenever accelerating onto a highway, my car's rpm's become completely sluggish between 2 and 2.5 . anything between idle to 2 and 2.5 and beyond the needle flies, but just between 2 and 2.5. if it was the maf, my car would die at 2.5-3k rpm, but i can redline very easily. just inbetween 2 and 2.5 its driving me nuts.