coil testing
 

Can someone please help me out here? Ive looked up how to test coils and found nothing but swapping out or unplugging coils to find the dead ones. The car is not running and think I have more than one dead coil. One of the forum pages explains checking ohms on + and G. When I did this I got nothing but when I checked IB and G I got the 1.5 ohms. Was the post wrong or is my coil sh!t? The FSM explains how to do it but I guess Im too retarded to figure it out.

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

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

measuring between the Pin 2 and Pin 3 connections:
reads 7.1 megaohms (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 megaohms

your car should run even with one or two bad coils.. the chances of more than that going at one time is pretty slim i would say.. and usually you get warnings for a while.. if your car just suddenly stopped running than i doubt thats your issue

Bad coils cause all kinds of funny issues. When I first bought mine I had a faulty coil, and it was causing an RPM flutter and stutter at idle, yet no codes were present. It even stumped an entire dealership mechanics team for OVER a month. They had to call in some guy from California to look at my car.

Typically though you're right, one, maybe two bad coils will make your car run like crap but probably won't stop it from operating.

Um, not so fast there...

I had a sudden no start condition happen after a brief trip to the hardware store. Car ran fine to the store, would not start when I came out. No codes, no warnings, nothing - I was stumped, had it towed home.

Took me 3 days to figure out what happened. ONE coil pack had shorted out, (primary side) & blew a fuse. I lost the 5 volt reference signal to all the sensors. I had a hell of a hard time figuring out what kept causing that fuse to blow.

So yes, ONE coil pack can indeed shut you down completely.

^^This is why experiences like this keeps us sharp on our toes and what to look out for. This experience is what makes this forum great.

AMEN! And I take no shame from correction on here. Hell I've owned my Max since 2000 and only started worrying about it when I paid it off thus joining this forum. I am not a mechanic though, I know what I know because of this place. I always concede to the ones who have more experience.

It's because of NJmax, Dennis, Americaner etc that I have been able to enjoy this ride for so damn long. 236k and counting

Well this is a long story so I won't bore you with the mile long list of new parts. Once in awhile it will start up and run for about a minute then stumble snd die. I tested all coils and am only getting the one reading of 1.6 ohms. Not any other ones. I get signal and batt voltage at wires and on coils. I need help BAD.

Please DO, actually. We need to know what you have replaced in order to (ideally, in a perfect world) rule them out.

More detail on the problem please.

** Do you have any codes (is your Check engine light on)? If YES, post what they are.

** Does your car start up fine? Does the car not start at all?

** What have you done to the car in the time preceeding the failure?


Without having any info (which makes this a wild-azz-guess), knowing our 4th gens, if the thing doesn't start at all (or long time to crank, then start) I'm thinking starter is bad or the engine grounds are not up to snuff (like if the trans was removed, that mating surface needs to be sanded down...)

When I boight car in 2004 it ran great. O2 sensor fell out of cat and I kept driving. Over about a month it ran like crap. Longer start ups. I decided to change exhaust and cat and 3 o2 sensors. Replace timing chain complete. Yes....all lined up. Car ran like crap still and running rich blowing black smoke. Along with TC replaced water pump, belts, hoses, VC gaskets. Cleaned UIM and IAC valve. New ngk plats. Parked it. New crank sensors....both. Cam sensor, TPS, fuel filter, fuel pump, check fuses, check relays. Second new starter 3 days ago. New ign switch, crank pully, new harness from front crank sensor to ecu. Replaced ecu, ngk plats again, new IAC valve. Replaced PCV lines, hose and valve. Think that's it. 135000 miles, no start. Intermittently getting spark. New injector seals, they pulse too. Checked them already. Engine floods with gad. Plugs wet. New battery. Sorry ths is a mess but typing from my phone.

Also no codes. Flash code 47 comes up from cranking and running battery down. 82 from the metal shavings of the starter. Second replacement starter. All wires from ecu were checked for voltage and ohms. No breaks in wires. Aggravated.

maybe a crappy ground coming off the ecu? Check the wiring harness coming off the maf, maybe broken wires or bare wires... sounds like an elctrical issue. Something is shorting or grounding out somewhere. Maybe check the harness running to the coils, something could be shorting out there and throwing everything out of whack.

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Both those codes for BOTH of your crank sensors will cause a no start issue. Better double check the sensors and make sure they are actually good before you keep guessing on other things. I know you said that 0407 came up when you drained the battery, but I had the same problem with the cam sensor causing a no start, that the code did not come up until i drained the battery. Replaced my cam sensor and it started right up.

Both sensors are new along with the wiring harness. I made new harness due to this. The sensor under pully is a new Nissan part. Only comes up while cranking when battery goes liw. Also, while cranking there is hesitation almost like hydro-lock. Added several grounds and all new battety cables.

With the readings I got on my coils are they good? I don't get a Mohms reading. I'm lost on this now. I'm not new to fixing cars been toying since 1980.

Given the amount of money you have already spent, I would just go buy 6 new coils and swap them all out. See what happens.

If you still have the problem, it is not coils and you could return them.

In my experience testing the coils, I can only get the pin 1 and pin 2 readings. On the bad one I had recently, I got an almost identical reading yet it was bad.

Resistance readings are not 100% proof positive that a coil is good or bad. But as someone stated, one bad coil will not prevent the car from starting. The car will start with two bad coils. Don't know about more than two.

If the coils were slowly failing, aka the dreaded P1320 code, the car would start. It would take several totally dead coils to prevent the car from starting. You can remove a coil from the spark plug, leave it plugged into the wire harness and crank the engine and look for the spark. You will have to have the end of the coil close to the engine block, probably with a screwdriver or something metal in where the spark plug would go.

Based on what I am reading here, I don't think the ignition coils are the problem. I would test out the crank and cam sensors according to the FSM.

Cam and both crank sensors test good and are brand new. When I got the car some one removed the CEL bulb. Found out recently and fixed that. Dont know what codes were present earlier. Get spark at plugs out of engine SOMETIMES. This is killing me. Will Nissan take back coils if it does not fix this issue?

Probably not. They won't take back electrical items, so I think they're yours permanently. But ask them before believing me.