R33 s1 miss fire - urgent help needed pls

[Mr.R33]

Hey,

I recently installed a Power FC into my R33 S1.

other mods include FMIC 3 inch straight through from turbo

12 psi and pod.

When I first took it to my tuner to install and tune the Power FC it had a major problem with a major miss fire as soon as you put your foot down at standard boost using the standard ecu.

after replacing the spark plugs with a new set of NGK standard 0.7mm gap it fixed the problem. So he went ahead with the install and tuned it over a 4 hour period on the dyno.

My problem after that though is that as soon as you put your foot down now it kind of stutters a bit as it hits max boost before I get power. It is like there is nothing there for a second then it comes on again.

I tried re gapping the plugs - first to 0.9 mm which made it go back to having the original backfiring issue as well as this new problem. Then I tried re gapping the plugs to 0.6mm which just got rid of the misfiring issue still leaving me with the stutter for want of a better description.

Does anyone have any ideas / suggestions of what my problem could be?

Could the coil packs cause this issue?

If anyone could help I would really appreciate it.

Thanks

[hanyou]

had exactly same problem. it was my afm changed it with a z32 no more problems.. and on the way i changed my fuel pump/filter & sparkies vthen i got it tuned and it was perfect

[TTT]

why did you pay the tuner for a tune that wasn't good?

take it back to him.

[Mr.R33]

had exactly same problem. it was my afm changed it with a z32 no more problems.. and on the way i changed my fuel pump/filter & sparkies vthen i got it tuned and it was perfect

AFM?

wouldn't have thought that the AFM would have made that much difference.

but will give anything a go to fix the problem.

Thanks

[Mr.R33]

had exactly same problem. it was my afm changed it with a z32 no more problems.. and on the way i changed my fuel pump/filter & sparkies vthen i got it tuned and it was perfect

So you tested it after the installation of the Z32 AFM and it fixed the problem?

or did you only test it after you changed the fuel pump/filter & sparkies as well?

[blind_elk]

If you have had to gap the plugs down to 0.6mm (that's only slightly more than HALF the design spec of 1.1mm!) then you have a serious problem in the ignition department.

It's possible the acceleration enrichment needs some work as well.

[Mr.R33]

If you have had to gap the plugs down to 0.6mm (that's only slightly more than HALF the design spec of 1.1mm!) then you have a serious problem in the ignition department.

It's possible the acceleration enrichment needs some work as well.

The standard NGK plugs come out with a 0.7mm gap in them, so I only reduced it to 0.6 as the tuner suggested.

as for the acceleration enrichment, I checked my figures against another forum members and we had the same figures

Acceler.

5000 5.2 2.0

4000 4.8 1.8

3000 4.2 1.5

2000 3.4 1.1

1000 2.4 0.6

Water temp. Corrections.

+80 1.00 1.00

+50 1.09 1.15

+30 1.14 1.29

+10 1.25 1.50

-10 1.39 1.73

-30 1.29 2.00

do these seem right?

have borrowed some coil packs for the weekend, will try to replace my packs one at a time to see if I have dodgy packs.

The tuner thought this might be the case as he said I actually was low on power from what he was expecting, and thought this might be the problem.

does this sound plausible to anyone?

[readyGO]

can i ask where did you get it tuned? im in brisbane aswel..

[Sneeky]

I had the exact same problem, misfire after installing 3" ex fmic and pod filter.

turned out to be coilpacks, splitfires went in and fixed it up good now I run 0.9 gap and spark is strong right through.

my miss was more prevailant at higher revs but was hesitating from 3000 revs up most the time.

[Sydneykid]

The standard NGK plugs come out with a 0.7mm gap in them, so I only reduced it to 0.6 as the tuner suggested.

as for the acceleration enrichment, I checked my figures against another forum members and we had the same figures

Acceler.

5000 5.2 2.0

4000 4.8 1.8

3000 4.2 1.5

2000 3.4 1.1

1000 2.4 0.6

Water temp. Corrections.

+80 1.00 1.00

+50 1.09 1.15

+30 1.14 1.29

+10 1.25 1.50

-10 1.39 1.73

-30 1.29 2.00

do these seem right?

have borrowed some coil packs for the weekend, will try to replace my packs one at a time to see if I have dodgy packs.

The tuner thought this might be the case as he said I actually was low on power from what he was expecting, and thought this might be the problem.

does this sound plausible to anyone?

That's the standard (default) PFC settings, acceleration enrichment HAS NOT been tuned. Take it back and ask for it to be tuned properly.

PS; It has been my experience that 99% of the time when people blaim coil packs it's something else. Usually poor tuning.

[Mr.R33]

Does anyone know how to tell if a coil pack is stuffed?

with leads it is as easy as testing the resistivity with a multimeter.

But how do you tell if a coil pack is ok?

I have got a hold of another set of coils to replace my original stuffed coils ( to test if that is the problem) and I need to know if there is a way for me to tell which ones to replace.

Thanks

[rob82]

You can tell if a car is misfiring on a dyno as the mixtures will go lean, unless you are running a fuel that carries its own oxygen like C16. It actually sounds like an AFM problem though. What type of pod filters do you have as a few brands will actually break off and lodge on the sensor which will give you the symptoms you are describing. Would also like to know who did the tune.