Jump to content
SAU Community

Recommended Posts

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

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

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?

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.

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?

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.

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.

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

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.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Have a look at that (shitty) pic I posted. You can see AN -4 braided line coming to a -4 to 1/8 BSPT adapter, into a 1/8 BSPT T piece. The Haltech pressure sender is screwed into the long arm of the sender and factory sender (pre your pic) into the T side. You can also see the cable tie holding the whole contraption in place. Is it better than mounting the sender direct to your engine fitting......yes because it removes that vibration as the engine revs out 50 times every lap and that factory sender is pretty big. Is it necessary for you......well I've got no idea, I just don't like something important failing twice so over-engineer it to the moon!
    • Yup. You can get creative and make a sort of "bracket" with cable ties. Put 2 around the sender with a third passing underneath them strapped down against the sender. Then that third one is able to be passed through some hole at right angles to the orientation of the sender. Or some variation on the theme. Yes.... ummm, with caveats? I mean, the sender is BSP and you would likely have AN stuff on the hose, so yes, there would be the adapter you mention. But the block end will either be 1/8 NPT if that thread is still OK in there, or you can drill and tap it out to 1/4 BSP or NPT and use appropriate adapter there. As it stands, your mention of 1/8 BSPT male seems... wrong for the 1/8 NPT female it has to go into. The hose will be better, because even with the bush, the mass of the sender will be "hanging" off a hard threaded connection and will add some stress/strain to that. It might fail in the future. The hose eliminates almost all such risk - but adds in several more threaded connections to leak from! It really should be tapered, but it looks very long in that photo with no taper visible. If you have it in hand you should be able to see if it tapered or not. There technically is no possibility of a mechanical seal with a parallel male in a parallel female, so it is hard to believe that it is parallel male, but weirder things have happened. Maybe it's meant to seat on some surface when screwed in on the original installation? Anyway, at that thread size, parallel in parallel, with tape and goop, will seal just fine.
    • How do you propose I cable tie this: To something securely? Is it really just a case of finding a couple of holes and ziptying it there so it never goes flying or starts dangling around, more or less? Then run a 1/8 BSP Female to [hose adapter of choice?/AN?] and then the opposing fitting at the bush-into-oil-block end? being the hose-into-realistically likely a 1/8 BSPT male) Is this going to provide any real benefit over using a stainless/steel 1/4 to 1/8 BSPT reducing bush? I am making the assumption the OEM sender is BSPT not BSPP/BSP
    • I fashioned a ramp out of a couple of pieces of 140x35 lumber, to get the bumper up slightly, and then one of these is what I use
    • I wouldn't worry about dissimilar metal corrosion, should you just buy/make a steel replacement. There will be thread tape and sealant compound between the metals. The few little spots where they touch each other will be deep inside the joint, unable to get wet. And the alloy block is much much larger than a small steel fitting, so there is plenty of "sacrificial" capacity there. Any bush you put in there will be dissimilar anyway. Either steel or brass. Maybe stainless. All of them are different to the other parts in the chain. But what I said above still applies.
×
×
  • Create New...