Still Misfiring. Not Plugs, Not Coil Packs, What else?

[bless_you]

well kym, unfortunately xspeed only had a series 2 AFM so no luck there. i will have to try and find somone who has a series 1 AFM as i have a 94 model... bugger

so... no good news there (

[OVL-747]

as unlikely as it sounds but a broken ringland/piston can cause a miss under load.

whats ur fuel pressure regulator like?

a flogged out dirty catalytic converter also can cause problems.

this happened to me , i had a dry solder joint alomg my loom , midway along it too mind you , absolute prick to find.

could be that

[GTS-t VSPEC]

bless-you, I should have an AFm if you want to try it, PM me.

I agree with OVL-747, it could be ring-land causing the miss, lets hope not:D

[Max GT]

Hi I am new in the forum and I have the same problem. My car is R33 GTS-T 25T Series 1 Auto. I recently increased boost to 12 pounds and started to experience misfire only at full throttle (the car has a pod filter, cat-back 3" exhaust, Unichip, bleed valve and standard everything else).

I took my car to Nissan yesterday and fitted a new set of standard heat range 6, NGK Platinum plugs (previously Greddy Iridium, heat range 7), which improved the misfire problem a bit. However, idle rev has gone up from 660rpm to 760rpm.

Any thoughts will be much appreciated.

[macka]

Gday Kymmy!

sounds like over fuel for sure...

same rev range same boost range...

yeeeeep

Originally posted by Strich9ine

Cheers guys,

Well, I'll just wait until the AFC is in and tuned, and if it still does it, i'll be looking at the AFM.... daym!

Maybe it's better to go for a Z32 AFM ? How much are they in comparison to a stock AFM ?

crooser,

By single misfire, i mean, it gives about 3-4 big pops consistantly between 4000rpm and 5000rpm.. then power comes back on after 5000 and it runs fine till redline...  

so frustrating...

[WLD747]

After a full major service today thinking my misfiring/poping would disappper has not helped.

i ran 14psi on my r33 series 1 at 4000 - 5000 rpm she would misfire bad. I got a pod, highflow cat, 3'' exhaust system and a custom fmic. As a result i have to run the factory boost level to avoid this problem.

Anyone got definate solution to this nightmare we are all having.

Well heres my plan of attack in the next few weeks and will update this post with results.

1. Coils (another pair)

2. SAFC

3. Z32 AFM

4. Electronic boost controller (I might have a faulty bleed value_

If it doesnt get better im gona go nuts. any comment welcome as im runnng out of ideas

Thanks in advance

AK

[crooser]

borrow a known working AFM from someone before you go trying anything else. common prob

[T0nyGTSt]

As a last ditch effort, look at higher energy ignition.

I admit I know nothing about MSD type units - in fact I was surprised to see someone on this forum revert back to a VL style "distributor cap and 6 wire" type setup.

However some people have gone to Splitfire D1 coils and this solved their problem.

But they aren't cheap.

T.

[Guest RedLineGTR]

"Splitfire D1 coils and this solved their problem" yep heard about those too. I heard some rumours about people having some problems with the spitfire coils or something can anyone clarify any info about them.

[Mase]

Has anybody thought that maybe it may be a faulty injector/dirty injector??? An injector could be dirty and staying open a little possibly and causing overfueling in a cyliner. One of my plugs was blacker than the rest so im getting my injectors checked.

[Sydneykid]

HI WLD747, have you got a boost cut defeater? We have 700 bhp RB's running 1.5 bar with standard ignition, I don't think you need to look at upgrading.

[GunMetalR33]

Have not read the above threads so maybe i should keep my mouth shut but I like almost everybody on this forum have had flat spots like you!

I started a thread: http://www.skylinesaustralia.com/forums/sh...&threadid=23922

and got lots of suggestion most of which were fuel related!

All r33's are going to get a small flat when the cam changes position around 4500 revs. And a fuel modifier like a s afc or something should fix that. But if you are getting really bad ones then you should not rule out the air flow meter, ignitor pack or spark gap...

Spark gap has probably been suggested already but I had somebody change my gap from .80 to .76 which totally fixed the problem, so even the slightest change in gap can make a difference. I should also mention that I am running NGK iriduims.

Have a look at the link above there might be some suggestions there that could also help you!

[GunMetalR33]

Have not read the above threads so maybe i should keep my mouth shut but I like almost everybody on this forum have had flat spots like you!

I started a thread: http://www.skylinesaustralia.com/forums/sh...&threadid=23922

and got lots of suggestion most of which were fuel related!

All r33's are going to get a small flat when the cam changes position around 4500 revs. And a fuel modifier like a s afc or something should fix that. But if you are getting really bad ones then you should not rule out the air flow meter, ignitor pack or spark gap...

Spark gap has probably been suggested already but I had somebody change my gap from .80 to .76 which totally fixed the problem, so even the slightest change in gap can make a difference. I should also mention that I am running NGK iriduims.

Have a look at the link above there might be some suggestions there that could also help you!

[GunMetalR33]

s**t sorry guys!

[OVL-747]

Originally posted by crooser

borrow a known working AFM from someone before you go trying anything else. common prob

ill second that

[fatz]

CAS

make sure its not too advanced like myself

or too retarded like B MAN

try diffrent possitions and c if it changes the place where it misfires

simple an chick check

and if its not that instal sump baffels

Pete

[Ryno]

Sump Baffels? Wtf?

Anyone had the ignition module (black box on top of the engine) die on them?

I've got similar engine skipping problems, and after trying everything else, I'm thinking that may be the cause

[DAMQIK GTS-T]

rev210 is right the problem is ignition.

This fix has worked on 3 out of 4 cars that I have tryed it on including mine and hitnrun's cars,

Croosers car being the one that it didnt work for (he had a stuffed Afm).

Advance the ignition timing from 15 deg to about 22 deg. no more than 25 deg and then reset the ecu.

Regards

Damqik

[Mase]

how long does that solve the problem for tho??? I would think that the ecu would eventually go back to it's original behaviour over time???

[BigDatto]

Gunmetal has the right idea and I second his post re: .74mm gap with stock ECU on upped boost. check this thread, I just went thru the same BS and sorted it.

http://www.skylinesaustralia.com/forums/sh...5648#post555648

wishing you a speedy recovery !