[Andy Black]

Had new plugs fitted last a few weeks ago and now when revs go past 4500 till 5000 there is a splutter kind of sound from the exhaust and a quick loss of power. Go past 5000 and it's OK.

The garage suggested one of the sparks was bad and we fitted a new set. The problem is much less aparent now, but still there.

I have left the car with the garage for a month as I am overseas. They are going to check the spark gap and adjust to the recommended 1.1mm gap as suggested by Middlehurst.

Any ideas on the problem? Could it be the ECU? My coils are tiptop.

Thanks.

Andy.

 

[Max]

Plugs

I had similar problems with my R33, very intermittant bad midrange misfire under load, went through the usual things, fuel, airflow sensors, plugs. Speak to Middlehurst and get a set of their racing plugs. I warn you they are not cheap and I am not exactly sure which make they are but, as the saying goes, they did it for me!
Mail me if you run into problems.
Max.

PS. I am no mechanic but it sounds extremely unlikely that by messing around with plug gaps the problem will suddenly be cured, unless, of course the gaps are way outside tolerence.

 

[JasonO]

Eh, Is the recomended gap not 0.8mm ?

 

[hipogtr]

Factory plug gap is 1.1mm. So, if you're running factory boost and factory cold range plugs (ie. 6) 1.1mm is the way to go. If you're up on boost and down on cold range (ie. 7), a smaller gap may be better.

Cya O!

 

[JasonO]

I've just replaced my plugs, this is a photo of one of the old ones, I'd say it lt looks kinda healthy, its done about 5000 miles.

Just incase you can't make it out from the picture, it doesn't appear to be pitted, nor is the end of the electrode rounded away, the insulator has a slight but very fine redish tinged deposit but otherwise looks OK.

Can anyone confirm what a healthy plug should look like ?

 

[JasonO]

GAP Kids

I even got the youngster to GAP the new plugs

Start'em Young

 

[RonS]

Plugs

Andy/Jason,

That plug looks good to me, like the young 'un checking out the new one's, Cute

As to gapping I had a similar misfire, changed Greddy Iridium's gapped at 0.8mm, that sorted it

RonS

 

[Itchy]

Had the same problem

4500 till 5000 there is a splutter kind of sound from the exhaust and a quick loss of power. Go past 5000 and it's OK.

The garage had fitted platinum plugs but they where listed for a 300ZX and not a Skyline. Check that they are correct type / temparature rating etc.

 

[Andy Black]

So pound for pound, what is the best type of plug to fit, pls state brand and model etc, and also best gap mm'

The boost is up a little on standard.

 

[JasonO]

Yep,
Like RonS suggests, Greddy Iridium's, they were recomended to me, and they seem to work.

I'll even get the youngster to gap'em for ya

 

[SkylineNewbie]

I seem to have this problem now too!!!!!

I turned up the boost a bit and its making a slight misfire under load. It doesn`t seem to lose power, just makes a splutter from exhaust.

I`ve got Greddy Iridium tiped plugs and I took them out tonight and they are a bright Orange colour, is this normal?????

Steve

 

[Andy Black]

Well the end to a strange saga! I fitted 6 Greddy Iridium plugs to the car and the splutter has gone and the car is now much quicker to pickup and rev!

I was at the point of getting new coils and leads but thankfully all is well.

So if anyone needs a regular set of Champion plugs??

 

[MattPayne]

will that be a set of dodgy plugs that make yer car missfire...

 

[Andy Black]

Nope, a second set that did not fix the problem from the first set. they are good plugs! just not for this car. They fit Subaru and Toyota also.