Help Misfiring all of a sudden.

[Gav240z]

Well today I got into the Z and was on my way to check out a 2+2 for a friend who's in the market for one when my Z played up on me.

I started her up let her run a couple of minutes while brushing my teeth :classic: . She's been running a bit odd lately and I thought it was a carbie issue could still be but it seemed like it had been missing a little but was driving fine.

Last night I got her home no problems except well it seems like its outta tune.

Now this morning I'm driving out of my drive way and start to accelerate and it's missing like mad so I think maybe the choke is screwed as sometimes they don't open evenly due to been worn or sticky so I pull over pop the hood and fiddle with the choke seems fine(I've never had a problem with the choke).

I try no choke and same deal missing like mad give her a rev still not good.

So I drive along waiting to see if when it gets warmer she's ok but nothing and it's been starting to backfire aswell.

I check all electrical connections everything seems to be in order.

Now recently I replaced my spark plugs so I count them out. my distributor is electonic and the coil is new and a bosch unit. As I say car as been fine for a year or more since I've owned her.

I'm personally thinking spark leads as they appear to be a good brand(NGK) and I'm told they last forever there the see through ones. However everything gives up so I won't rule them out and probably before I have any reply to this I would have bought new ones anyway .

So if anyone can suggest anything at all that might also be causing this please let me know. As I say I think it's mainly electrical not carbie but don't wanna rule anything out.

Thanks

[carguyinok]

This is a real long shot. with the backfire and missing maybe a streched timing chain and it may have jumped one. Or maybe your distributor came loose and got a little turn on it?

[Zedrally]

Sounds electrical,

I would have suggested the capacitor, but you have an electronic dizzy.

Highly doubt it would be the leads, how long is the spark, check if it is weak. That will give you a better indication of where to start looking next.

[Gav240z]

Yeah didn't think it was the leads either, but still changed them the timing is set to 10 degree's or so but it should probably be around 5 with the 10:1 compression however i just checked it then and that was with the choke out so probably above 1000rpm.

I would have thought capacitor too but it's electronic dizzy.

I have a unique exhaust system and it's set so that the first 3 cylindes and last 3 cylinders split evenly into two pipes and come out the middle of the car like the works rally cars.

I noticed when i put my hand over each exhaust the left hand one is blowing alot more air than the right hand one.

I might give the carbs an adjustment but it really seems electrical cause when I rev it I can hear it miss. And even when one carbie is sucking more than the other you don't get that kinda missfire and the backfire however she only backfires a little when driving.

What about on the side of the coil there is a wire that goes to the thermostat but before that goes to the side of the dizzy and there is a little black box could that be causing problems????

[Zedrally]

Originally posted by Gav240z

What about on the side of the coil there is a wire that goes to the thermostat but before that goes to the side of the dizzy and there is a little black box could that be causing problems????

Have no idea what the little black box is?

Anyone else?

Since it's been modified, I guess you're on your own!

Good luck.

[Gav240z]

Little black box is a stardard item on the electronic dizzy. Forgot the correct name now, I pulled the 6th lead and found it makes much less difference than the others when i take it off but when i reconnect it, makes a little shudder as if it's firing a bit but not anything fantastic, electrical timing seems fine at about 11 degrees at 700rpm.

Next problem is I need to pull the plug and the socket I need, my childish step father has locked up the tool box with it in their because I apparently don't put things back properly at 21 you'd think he'd treat me like a grown up not a child, I've been buying my own tools lately in an effort to get him off my back .

By the way Nissan has those little black boxes priced at a pretty penny in the way of $800AUD. Hoping it's a dud plug will keep you guys posted.:devious:

[Gav240z]

Thanks for the help and suggestions guys I worked her out.

Turned out to be a fowled spark plug on cylinder 6.

I pulled 1 plug at a time while she was running and noticed 6 made F' All difference .

Pulled it out changed it with a spare plug I had in another engine and she was fine.

Believe she's running a bit rich but nothing I didn't know already.

thanks again and I'm so relieved hehe.

[toecutter]

Had the same problem about two months ago. The plugs were only 2 weeks old so I did'nt think it would be a plug and surely enough after ripping half my hair out it was a fowled plug. Sorry dude, just read your post now.

[Gav240z]

No problem . Did you mean the meet was this saturday or the next ???? Doesn't really matter I guess but I know a few Zedders who would like to meet up real soon in the Melb area so sooner you let me know the earlier I can let them know and more likely they'll be there.

Speak soon dude.:classic:

[toecutter]

Well I've been hoping to get something organized for a Sunday afternoon at the Elwood beach car park, with a few beers and a barby. It has been hard to get a date that is mutually free for all. Lets set a date-How would next Sat or Sun arvo be for you! I can set it for either and we'll then send out the word!?!?

[Gav240z]

SO far saturdays are best however I will be consulting my manager at work regarding my hours they've been screwing me around since i started mainly cause my manager was fired 3 weeks into my training.

I'll let u know tomorrow night or monday cheers.

[toecutter]

Cool-will be good to get a few of us together. Good opportunity to take some pix. You mentioned you know of a few fellas that will drop by. Sounds good. I expect there will be at least four guys with early zeds coming and perhaps a couple of newer models. The more the merrier!!!