Momentary misfire after hitting limiter.

Nissan 300ZX technical discussion forum: Maintenance, performance, installations, modifications, how-to's and troubleshooting.
User avatar
zxFarside
Posts: 281
Joined: Wed Jan 13, 2010 6:11 pm
Car: 94 300zx TT (sold)
03 Suburban 5.3
00 BMW 323

Post

So here is an oddball issue Ive been with. When I hit the rev limiter the car develops a brief misfire. This happens when I'm in park/neutral or under boost. I can throw 18lbs at it and as long as I don't bounce it off the limiter its totally fine.

It seems like its down a cylinder, but then comes right back in less than 10sec. 2 of the coil-pack plugs were broken so they are rtv'd in place. Spark plugs look good. It's hard to tell which cylinder is misfiring because it comes and goes so quick.

The only thing I can figure its either the coil-pack plugs are still loose, an injector getting stuck, or o2 sensors going out(I've never changed them and my tune its really fat so possibly they are starting to foul.)

I dunno if thats anything anyone else has experienced?


User avatar
NolimitZ32
Posts: 7112
Joined: Fri Jun 27, 2008 9:07 am
Car: 91 AG2 2+0 TTMT swap/E39 BMW 540i6/E53 4.6is Dinan S3
Location: Houston, TX

Post

What injectors are you running? Could it be that they are getting lazy or you're pushing them to 100% and they are having a hard time closing?

User avatar
zxFarside
Posts: 281
Joined: Wed Jan 13, 2010 6:11 pm
Car: 94 300zx TT (sold)
03 Suburban 5.3
00 BMW 323

Post

DW 740s

It boosts just fine, when its turned up, it peaks at 20psi and hold 18psi with no breakups and fat afr numbers.
Really as long as I don't wot through the 1-2 shift or bounce it off the limiter in the driveway it doesn't happen.

User avatar
NolimitZ32
Posts: 7112
Joined: Fri Jun 27, 2008 9:07 am
Car: 91 AG2 2+0 TTMT swap/E39 BMW 540i6/E53 4.6is Dinan S3
Location: Houston, TX

Post

Without looking at your maps its hard to tell but the only other thing it would seem to me is either a lazy O2 or an issue with the tune coming off the limiter.

User avatar
zxFarside
Posts: 281
Joined: Wed Jan 13, 2010 6:11 pm
Car: 94 300zx TT (sold)
03 Suburban 5.3
00 BMW 323

Post

I may look at putting in new o2, since it wouldn't hurt to get fresh ones in there.
I wondered about the tune, and its relation to the transmission. I think the rev limit is set at a M/T level and I have a slightly taller tire on, so if it revs too high the trans module gets confused then the ecu gets confused. The trans is also heavily built. If I can lower the rev limit some it may solve it.

Martino
Posts: 2
Joined: Fri Feb 29, 2008 1:30 pm
Car: 91 Nissan 240sx
Contact:

Post

Bumping and old thread, but did you ever figure this issue out? I'm having what seems to be the exact same symptoms and have not been able to sort it out.


Return to “300ZX (Z32) Technical”