FLO_BOY

hi there!

OK, so after some researching the topic, some folks have suggested
that to check the coil packs I should unplug one and see what
happens to the RPMs...if they drop, that coil is cool...if it doesn't
drop, then that is the bad coil.

BUT, just like everyone who has my symptoms, they are sporadic.

So, if the problem is sporadic it is HIGHLY possible that if
I had a bad coil pack, but it wasn't "acting up" at that moment,
the RPMs wouldn't drop??? Isn't this correct????

PLEASE HELP!!!
FLO_BOY

$tillen$ux

sucks huh? I had to go thru this. Why are so many maxs having this prob anyways? Its such a major prob! anyways, in my case, I swapped a new coil pack and left it there for a couple days (since I usually get misfires every couple days) and changed cylinders til it didnt msfire anymore. I think its the only way to do it w/out testing. good luck though!

FLO_BOY

Yes...very much so.

OK, now, called Nissan (actually, Infiniti) and ofcourse they said
that I need to replace all 6 because of voltage differences (WTF?,
this makes NO SENSE, except NONSENSE!!!)

Anyway, another dealer parts guy had a good point:

-- If a coil is bad, I should be able to determine it by looking
at the spark plugs, because the spark plug for the one bad coil
will look different than all the others.

THIS kinda makes sense to me...anyone have an opinion on this?
Oh, and any info on my original post would be appreciated to!

cheers! and Happy Thanksgiving!
FLO_BOY

D1NOnly34

iTrader: (4)

My car was doing horrible, knock sensor was going crazy, basically it felt like a cylinder was misfiring do to the extreme loss of HP and sluggish acceleration. I changed my fuel filter, knock sensor, and spark plugs. Even went the extra step to add some octane booster to see if maybe too low octane was causing my engine to knock or jerk. I did the coil pack test..remove each one by one to see if they work. After each time I removed the harness, the RPM's dropped, which meant that they worked right? Well, you see, when I was changing my spark plugs, I wasnt able to change the middle rear one due to the fact that the coil pack was broken, and by broken i mean that the plastic end had disconnected form the whole pack itself. Even though its only plastic and is just a covering for the coil, it did make a difference.
I finally rigged the coil pack by putting some super glue at the end, pushing it back in, waiting a day, and pulling it out again. This time the plastic end came out too, thus enabling me to change the spark plug. I also changed the coil pack cause I didnt want it to stay in there the way it did. After changing the pack and the spark plug, my car is fine, and I can feel the gain in HP again. Basically what Im saying is, it could be a spark plug not getting enough spark, or maybe a coil pack is bad, even though it seems like its good. Try doing these changes, trial and error is the best way for me.
Oh yeah one more thing, I actually went to the dealer before I fixed my car cause I was desperate to fix it. I told the guy my problems and he told me straight out it was the coil pack. I told him I did the test and he said "the coil pack may seem to be working, but maybe its not getting enough or any spark at all"...It didnt make any sense to me, but when I fixed my car it did. The coil, after the test, gave the impression that it was working (RPMs dropped noticeably). Changed it and the spark plug, everythign was fine. Hope this can help, if not, then I typed all this for nothing!

FLO_BOY

These few lines here do help -- Thanks!
FLO_BOY

KWheelzSB

iTrader: (1)

I had the same symptoms as you: sporadic, inconsistent loss of power on WOT accelleration & thought it might be the knock sensor, (because of all the bad press it's been getting lately), so. . .

With the engine idling, I tested the K/S with my multimeter and it was putting out the 2.0-3.0 volts it's supposed to, so, on to the next potential source. . .

I then checked the coil packs (again, using the multimeter) on the front cylinder bank (to check the rear-bank coils, you need to remove the upper intake manifold) and found that the resistance was off-the-charts high on the middle, front bank coil = it was fried.

Just to eliminate the possibility of a fuel blockage, I replaced the fuel filter. Additionally, I listened to the fuel pump priming when the ignition switch was turned to the "On" position and it sounded normal - if it sounded weak, or different than normal, it would be worth a closer look.

Also, I used a mechanic's stethescope (3' length of standard automotive vacuum hose) to listen to the fuel-injectors, individually. They all sounded the same at idle, as they should - if you notice one or more doesn't sound the same, that's worth a closer look.

I replaced the bad coil and although I'm not totally convinced the problem is 'completely' gone, the engine's not acting up nearly as badly as it was before I serviced it. (I still need to pull the plug from the cylinder and clean it - it may have become fouled as a result of the bad coil).

One of these days I plan to check the rear bank coils to see if any of them are acting up as well. . .

See also:

http://forums.maxima.org/showthread....5&pagenumber=2

Great step by step insights on K/S, coils, O2 sensor diagnoses.


Hope this helps - good luck!

KWheelzSB

iTrader: (1)

2 Answer your Q specifically:

-If the coil IS performing properly at the moment of this test, you SHOULD expect the RPM's to DROP.

-If at the moment of the test, the coil in question ISN'T performing properly, you should see no change in the RPM's.


Theoretically speaking, if you were to perform this test on each coil, whichever coil(s) caused the RPM's to drop when unplugged would (theoretically) be ok.* Not sure how you'd do this test on the rear-bank coils tho - don't think it's possible. Also, since you already know the problem is sporadic, you can conclude that this testing method is flawed from the start.


*buy the multimeter & Hayne's manual. You'll be amazed how many times over they'll pay for themselves. I'm no rocket scientist - I just read and follow directions. If you can make Mac & Cheese, you can do this stuff, easy.

FLO_BOY

...and I have both a multi-meter and haynes (or is it a chiltons?) manual...I have a couple more new posts to make on this, so, this
isn't solved just yet.

take care y'all! ...and Happy Thanksgiving!
FLO_BOY