Sup guys. I did my front valve cover (bank 2) yesterday and this morning i went to go to work and my car sounded like it had a misfire. I went to check under the hood and noticed one of my coilpack connectors (cyl 4) had the prongs loose. Since im mildly retarded and was in a big rush to not be late to work, i was f ing around trying to get them back into position properly while the car was still running and something must of touched in a bad spot because my car died and wouldnt start. Woops. Ended up having to hitch a ride to work but when I got home I found out that a fuse blew (ENG CONT 1, or 2, i forget which), which was why the car wouldnt start. I replaced the fuse, the car starts, but now the misfire is worse than it was originally. I pulled all three front coils and it *appears* that they are ok, they all show similar resistance ratings to one another. However, it seems that either all 3 of these coils are toast, or there is something else electrical that is now faulty because of my idiot move. Keep in mind there were zero issues before i did the valve cover, battery was unplugged as well during the whole job just in case.

With the engine running, i disconnected each of the bank 2 coils in question one by one, and it had zero effect on how the engine was running (poorly). I reached behind the intake manifold and pulled cylinder #5 coilplug, which immediately had an effect (motor running VERY poorly), which confirms the misfire problem is almost certainly confined to the bank 2 cylinders. I find it very hard to believe all 3 of bank 2's coils would take a dump at the same time (unless they all got shorted or something??), which leads me to believe something else electrical is at fault - the fact that i blew the 15A fuse for ENG CONT 1 (or 2, again i forget which one) supports this theory. Trouble is i cant figure out what the problem is.

*All connections hooked up, all hoses connected. Confirmed not to be an exhaust or unmetered air issue.
*All coils on bank 2 have similar resistance values when tested with multimeter
*All coils on bank 2 have no effect on engine idle when disconnected with motor running
*Only relevant code is P0300 - which considering the circumstances is not very helpful. CEL light flashing already told me that much.
*I dug out the ignition condenser, and multimeter testing appears to show that it is in working order. Resistance rises until reaching infinity and stays there until discharged, repeating test shows same result. If i read correctly, theres only one condenser, which means itd be supplying the rear/bank 1 coils as well - meaning if this was faulty, the rear bank would be suffering also.

Thoughts on what could be the problem? I thought maybe bank 2 CAM POS sensor but wouldnt that mean the car wouldnt start at all if that was faulty? Or would it just result in the problems im having now? Im not seeing any code for it either, which is why im skeptical thats the cause... Is there another fuse or something that i missed besides the ENG CONT one in the enginebay? Is it possible i fried something in the ECU? Isnt the ENG CONT fuse supposed to blow to stop that from happening, also wouldnt that result in many other problems besides the bank 2 coils not working?

Im sure im missing something here. Searching the forum is leading me on a wild goose chase so i figured id send up some smoke signals for a helping hand while i continue searching. Could VERY much use the help because not having a car is pretty lame lol. Thanks.

 

What year is your car ?
I assume there is no spark on any of the B2 cylinders. If so, the suspects are: spark plug, coil, coil harness, condenser, crankshaft position sensor (incl. harness), and the ECU itself.
Can you arrange for a test with a "spare" coil?

 

2002 maxima
Update: Just did a spark test for bank 2 cylinders - surprisingly they are actually firing, which is good news in my eyes because that at least means its extremely unlikely the ECU got toasted. Going to see if i can get my hands on some coilpacks before work today, will check in and let yall know how that goes. Still find it hard to believe that all 3 could take a dump at once but i guess anything is possible at this point. As far as crankshaft pos sensor - wouldnt the car not start at all if that was toast? Same deal with the cam pos sensor - i read the motor wont start if that sensor isnt working, could be wrong though. In either case Im not seeing a code for anything other than random misfire (P0300) and my o2 secondaries (unrelated, theyre disconnected because of headers, will be sim'ing them soon).

EDIT: Going to have to wait until monday for coils... Local JY wants $50 per coil which is just straight up robbery. Nissan, predictably, refused to be bested with this nonsense, and set their price per coil at $100. Ended up buying 3 new hitachi coils off rockauto for $35 per. In the meantime if anyone has any ideas im all ears, thanks again.

 

OK, so you have spark.
Assuming the spark is there with B2 coils in place, replacing these coils may not help. (Makes you wonder about fuel ..... )
Unless you tested using one of the B1 coils ?

 

I had a problem like that, lazy me took me long time to actually work on it. I tested the coils and they were perfect on the range, bought 2 used coils moved them around and the problem is gone. Check all the connectors, test them and check codes if any. Had code po300 an 302. Good luck

 

 

You might as well buy new units off Rock Auto (Hitachi, Denso, or NGK)...I was fortunate to find a 4th gen in the salvage yard with alot of new items installed on it, and the coilpacks were Hitachi brand and the salvage yard charge me $8.31 each...Make sure your spark plugs are torqued in and not just hand tight!

 

If you happen to have an ole school timing light you can observe each cylinder's coilpack by attaching inductive pick up around the coilpack wiring harness...You need to make sure you don't have any cracks in the coilpack boot(s) , you should check your spark plug condition
https://www.rockauto.com/en/moreinfo...356780&jsn=486

 

 

Not a big surprise to me. But let's go back ....

How did you determine that "they are actually firing" ? Did you remove the spark plug(s), place it/them on the engine block, and observe the spark plug while your helper was cranking the engine ??

Let us know. Waiting for your response ....

 

I did not, i simply pulled the coils and ran a spark testing device between them and the plugs. Device lit up, the coils are getting power and making spark. Considering my plugs are fairly new (NGK iridium, replaced last winter), and they dont have any moving pieces or internal components that can really break besides the electrodes themselves, I figured they would be the least of my problems. Are you saying that they could have been destroyed in the course of 30 seconds or so from the shorting incident? Forgive my ignorance but Im not understanding what difference pulling the plugs and observing them making a spark at the gap would have if I already know the coil is already delivering a visible blue spark, which is in turn in contact with the plugs. Ill check it out tomorrow anyways but if you could explain your logic behind that, that would be great. Again i appreciate the help.

Edit: If you could recommend a good way of doing this that would be awesome as well. From what i understand, I should be taking the plug out, connecting the terminal to the end of the coil, and observing the spark that the plug is making? Again forgive my ignorance but should I have any concern about arcing or shorting or will that spark be contained to the gap because its the path of least resistance? Also do I just keep that spark plug tube open while this is happening? Again much thanks in advance.

 

That's a pretty good test, but the fool-proof test is what I described above (observe the spark on the plug itself, removed from the engine and grounded).
Note that the spark plug could be damaged (e.g., cracked insulator,) and not produce a spark.

With spark existence proven, it's either fuel or compression (lack of). Fuel delivery/injection would be the obvious next investigation target.

 

 

 

 

So good news and worse news.

Good news is that I got NDS2 to work, turned out my first cable was faulty. Got my new ECU synced with my key and got the car to start.
Bad news is that the problem was not the ECU. I am still not getting power to bank 2. Deactivating cylinders 2,4, and 6 results in the idle dropping maybe 50RPM per cylinder, which suggests they are indeed doing something but not much. Deactivating any of the bank 1 cylinders, predictably, results in the car sputtering and ready to die.

Unless there is some sort of sensor or electrical component i missed (PLEASE shout it out if youre reading), im starting to fear that the cam chain for bank 2 jumping timing somehow. I dont understand how that could be possible, but i am completely out of ideas on WTF could be causing this. Timing being off for bank 2 would make sense, since its still getting fuel and spark but compression apparently isnt taking place? I have not done any compression test yet, obviously that is going to be my next course of action. I just dont understand how an electrical short could cause timing to jump though, its just not adding up to me.

Is there a way to check the timing on one bank of cylinders without pulling the timing cover or any crazy sht like that? If it is indeed the timing, would it be cheaper/better to just swap a new motor in? Or to have the timing reset? Im not familiar with internals or any of this more involved stuff, idk if this means my motor is toast (again, if it is indeed the timing being off).

This REALLY fcking sucks. I was banking on it being an issue with the ECU, and it clearly isnt. Again, coils, plugs, injectors, VVT solenoid, cam sensor, fuses, ecu all seem to check out as ok. Next step is compression test but if anyone knows of something besides what i listed that i could also check that would be awesome. Wish me luck, i really fcking need it now...

 

Why would you think it's not possible? If it was working fine until you did your valve covers then back up and remove the valve cover and take a look at a what might be wrong....I still would perform a compression check, and while you have that valve cover off place #2 piston at TDC and look at the cam to ensure that only base circle of the lobes are contacting the buckets and the shims are not under a load (rotatable)...Did you ensure that the wiring of the three bank 2 cylinders are proper to the point of a pin to pin check....I would check each wire to ensure it's not grounded... Each connector to make sure you didn't damage the connector pins by front probing them...Check if the harness is damaged by possible bending to much, causing those dry, brittle wires to break or damage themselves? Remove all of bank 2 ignition loom and visually inspect for damage...You are sure that the Coilpacks are all firing? You are sure you didn't disturb the Fuel Injector harness or get a part of the harness caught between the head and valve cover? I would take some things apart on bank 2 (The Easy Bank) and look at what I did that may have caused this issue...Good Luck! Sometimes it's necessary to take a step or two back in order to go forward...

 

Got around to doing a compression test on bank 2. Cylinders #2 and #4 checked out at around 160-170psi. However cylinder 6 is showing only 70psi. At this point regardless of other factors, the motor is toast as far as i see it. Im not quite sure if the loss of compression on that cylinder can explain why the whole bank is having issues though.

At least i have some little piece of closure, i guess. Right now im weighing my options with how to proceed. I already have a lot of parts invested into this car (or rather, a 5.5 gen) so im leaning towards staying in the maxima game. Couple of ideas i have so far:
1)Buy another maxima. Really not looking to do this as the one i have now is clean and has no other issues, it was originally a florida car so the underside is in excellent condition by NY standards.
2)Swap in another motor. Probably my easiest option, however junkyard prices for a 02-08 motor are not the greatest and mileage is fairly high (over 100k) for going through with a swap.
3)5.7 swap. This is what im leaning towards. Not only are the motors around me more readily available, they are somehow cheaper AND lower mileage - already spotted a couple that have fairly low miles (~70k) and come from maxima's with rear end collisions... It seems like a no brainer to go this route considering the WHP gains the HR motor will give me.

However. I do not have a garage, nor a cherry picker or an engine stand. Buying an HR motor over a DE would save me enough money to buy these, but i still need to work out the logistics of how id get this done. Im thinking of maybe pulling the motor in my driveway or my backyard, and then transferring it to the back of my pickup so i can move it to my shed where i have a reasonable workspace, and once its done moving it back to my driveway to transplant it back into the car. I have never done a motor swap or anything that indepth, so it might be a little bit of a shtshow, but i think i can pull it off if i pick away at it carefully and meticulously - the guides ive been reading the last few nights make it seem like its doable as long as you are keeping track of what youre doing, and doing everything "by the book".

An alternate option, of course, is to buy a motor and have a local garage install it for me. This would mean paying A LOT of money that I dont really feel comfortable spending right now, considering i just cut back on my work hours to accommodate my uni schedule. It would also mean going the HR route would most likely be a no go.

So yeah, bit of a change of direction here... Thanks everyone for all the advice and direction you gave me thus far, I really appreciate all of it. If anyone has opinions on what I should do next, ill certainly hear you out. As i said right now im leaning towards tackling an HR swap but if anyone thinks that is unwise let me know. OR just give me encouragement, that works too lol.

 

You did perform that test with the throttle Wide Open? To bad you couldn't lease garage space somewhere...

 

 

dang ! sucks you had to go thru all that time and parts and effort to realize it was compression. glad you have closure though and hopefully u can utilize some of the parts, or sell them! sorry to hear the worst, but hope you new plan will work out.

 

Sometimes she goes, sometimes she doesnt go - thats just the way she goes. Appreciate the kind words lol.

 

How was the engine running before you replaced the valve cover gasket? It seems really coincidental that a cylinder would lose compression the day after you replace the valve cover gasket. Could something from the job have caused it? Even messing with coils/wiring while it is running shouldn't impact compression.

 

Engine was running great, had no issues, i was running headers and the precats looked healthy when i removed them so i know thats not it either. Other than the leaky valve cover which is what started this whole sh!tshow, there was nothing wrong with the car. I didnt check compression until the very end because I too found it to be such an unlikely scenario when there was no previous issues with the motor. The gauge doesnt lie though, cylinder #6 is toast. My best uneducated guess is that the timing must have somehow jumped on that bank of cams and some valves got bent. IDK honestly it doesnt really make sense to me either, but at the end of the day what I do know is that I need a new motor now.

 

Good Luck...I saw your new thread....