Reign_Man

so i just changed out all the spark plugs today with the same kind that were in it before, ngk-r, it worked perfectly before i did this, im not sure if i bumped sumthin or wats goin on but i barely have ne power to my car at all, very bogged down and sounds like the whole driver side of the spark plugs is misfiring, ne suggestions, PLZ HELP!

*ICE*

iTrader: (48)

take it out to see if everything is ok, no crack, break, oil, or burn marking on the plugs.. If there is a misfire, you should definitely see a check engine light on the dash..

3-fifty-WeEe

do u do the plugs thru the plenum?

binder

iTrader: (8)

wtf


anyways, it sounds like you clipped the wrong wires onto the wrong coils. Check the numbers on the wires and make sure they are hooked to the proper coil on the plug.

passenger side from front to back: 2 4 6
drivers side from front to back 1 3 5

I think it's common to get the 4 and 6 or the 3 and 5 backwards since they are very close to each other coming out of the wiring harness.

and like stated above, if you have them backwards and are getting misfire the "service engine soon" will come on the dash.

demundus

im actually having this exact same problem right now. replaced the plugs with the NGK plugs as the manual says. For argument's sake i never unplugged the coil packs from their respective wires, I just lifted the whole harness off as I unbolted the coil packs from the block. I put it all back together I assume correctly since there was never any "wire pulling" done in the first place. I'm getting VCD SLIP and CEL, throwing codes P0102 P0133 and P1136

HELP!

demundus

ECU reset, throttle body reset, all codes gone now, still a super rough idle, smoke from the exhaust, heavy gas smell, and no codes being thrown. Do i need to let it sit for awhile?

binder

iTrader: (8)

that doesn't sound right.

i wonder if something else didn't get accidentally removed or something. with the gas smell i'm thinking you still are misfiring which would push out raw fuel in the exhaust.

You can keep the wires attached to the coils and still flip the coils around. the wires on the back 2 of each side are long enough to get them twisted incorrectly. Go visually look at the numbers on the wires and where they are attaching.

demundus

binder- thanks for the idea. I actually did that twice since my last posting. I had someone else check the car over as well to make sure i wasnt missing anything stupid. everything is put back in order (numbers match) and the plugs are gapped correctly (a fear of my own i had to double check). I was able to get it to throw a code if i try to rev it while idling. I get P0300. Multi misfire. After I got that code I took it all apart again and made sure nothign was missing, including checking the plugs AGAIN and checking that the coilpacks were secure. Its going to the mechanic on the trailer tomorrow unless i get some feedback tonight.

The ONLY thing that went "wrong" during the initial plug swap was that I pulled the coolant hose near the driver's side plugs (middle plug) in order to get the coil pack out. I did this because, as stated earlier, I did not disconnect the wires, I just lifted the entire set of coilpacks up and off. The coolant hose spit some coolant at me, but that was the only notable thing that happened. Everything else was cool-runnings.

Reign_Man

i dnt knw about u guy's Z's but my coil packs will only go to certain cylinders, like the wires cant b twisted or nething as not to put them in the wrong hole, i got the check engine light ofcourse, im wonderin if maybe when i put the plugs in i may have twisted to hard on one and crack the damn thing, im in the air force and its hard as hell to find time to work on it, esp. since nissan decided to put a million things in the way of the plugs lol, ne suggestions i would greatly appreciate

demundus

Ok so, after Binders words are echoing in my head, i go out for one final check.


4 and 6 are indeed switched. It was actually not that hard to tell, and i feel like a RETARD for missing it. Problem solved. I have another minor issue that I see now with the cover off, im going to take a picture and start a new thread another time though...

thanks binder!

binder

iTrader: (8)

really? i spent 6 years in the army and 9 times out of 10 i was bored out of my mind. They don't work you 16 hours a day so a 30 minute plug change shouldn't be too terribly hard. I'm in med school and i'm a teaching assistant for the unversity in radiology. Next weekend i'm pulling my now possibly blown engine from my z to rebuild it.

Go check again, i'll put money on the fact that they can get switched. If for some weird reason they didn't get switched check the wires going into the connectors. I had one back out on me once. I would only get the p0300 code randomly and it was usually when i was in higher rpms. It was so random i was confused. Tore the car down time and time again. I pulled the plugs and isolated the cylinder by finding the plug not firing (it was white due to the misfire). Once i found that then i checked those wires and found 1 wire backed out far enough from the connector to make intermittant connection. You can check that too, but my money is on a slight mistake with 3/5 or 4/6.

It happens, like i said it's a VERY simple oversight that a person could even miss after checking it a few times. Don't feel bad about it. I'm glad you got it all fixed!

Reign_Man

alrite ur rite i dnt work all the time but it is hard with the hobby shop closin before work is out, neways if nething its gotta b its gotta b the back 2 on the driver side, but the wire from the middle does not wanna reach, so wat about the idea of a plug gettin broke when i put it in, cuz everything was runnin perfect before i changed them out, but my main question is about those wires not bein long enough, ne words of advice binder

binder

iTrader: (8)

Ya, as i read my words i was kinda sounding like a dick. It's finals week here and with my engine being possibly blown in the car last weekend (at least a head gasket at for now) i'm not in a good mood. I didn't mean to sound like that.

I understand your frustration. I was there when i started working on these cars. The more you work with it the faster you can tear it apart and you'll see it's not bad, it's just different than anything you've probably messed with before.

About your plugs being in the right position. The plug wires should have numbers on them. Just double check they go 1,3,5 drivers and 2,4,6 passenger from front to back and you're good. If that checks out then one of the plugs or wires could have come slightly loose when you moved things around. Unclip the connector at the plug, then hold the connector and gently pull on each wire trying to see if it's tight in the connector. If one pulls out somewhere then that's your culprit.

wires not being long enough: with our cars position and routing are key. Everything fits like it should WHEN it's properly routed. One thing out of place and it will make things not fit at all and drive you nuts. Might be the case but might not. If you just look at the numbers on the plugs and trace that wire to the correct cylinder then you will know if they are on. If they are on then you can rule that out.

Also while you are in there you could pull the plugs and set them on your work bench and number them. If one of them is more white than the rest then that ist he plug that is misfiring. Go to that cylinder and check evertyhing about it. That's how i found my misfire.

Chances of "breaking" a plug is highly unlikely unless you dropped it on the ground before you put it in. I guess if they are iridium tipped you could have snapped a tip off when gapping it which could cause a misfire. When you pull the plugs inspect the tips also.

Next thing after that is the possibility of a randomly burnt out coil. It's odd but i guess it could happen. Generally you will get a cylinder specific code and not the p0300 random misfire code. All things can happen. You would find that cylinder by checking the plugs OR you can start the car and let it idle. One by one unconnect each spark plug wire and listen to the engine. If you unplug one and the engine doesn't change the way it idles then that is the "dead" cylinder.

Reign_Man

u didnt sound like a dick lol dnt worry about it, but neways im gonna try those things tonite and c wat happens, ill give ya an update then, i appreciate it man

sunburst350z

iTrader: (1)

I had the exact same problems when I changed the plugs a year and a half ago.

there seemed to be a misfire on the left bank and no cel came on, raw fuel smell and backfiring under a medium load, and would stall occasionaly. I bought another 3 spark plugs and installed them and the problem went away. I have no clue as to what cause the problems other than maybe a bad batch of plugs. my coils were all correct and I swap em out one at a time as to not get confused. needless to say im scared to change em again

binder

iTrader: (8)

very rare to have a bad batch of spark plugs. It "can" happen but with quality control as high as it is for NGK i doubt it. Unfortunately since that didn't just happen you probably don't have the plugs to diagnose any issues from them to see if there was a certain plug not firing.