New problem with 32R - missing with new plugs

[Ronin 09]

Another problem has surfaced with the 32GTR now. A few days ago it wouldn’t start having sat for about 5 weeks and driven very rarely. As it turned out the plugs were fouled, and so were replaced. They were copper Bosch plugs, and were replaced with Iridium plugs (before anyone says they’re a waste of money, they cost 60 bucks).

The car has developed a misfire. It does it more or less across the rev range, when half to wide open throttle.

The new plugs are pre-gapped at 0.8mm. Modifications to the car are very minimal – turbo back exhaust with split dumps, removal of ‘boost restrictor’. Running Mobil 8000, Motul 300V.

Why is the car missing??? Boost cut? AFMs maxed out? I don’t get it! It is getting frustrating.

Thanks for any suggestions

[Amaru]

Does it miss at idle?

On idle disconnect a coil pack, see if it makes a difference to the way the car idles and tbhen plug it back in. Do this one by one for all coils while the car is running. The coil you unplug and doesnt change the idle of the car is the stuffed one (if they're good when you unplug them it will start idling funny)

Hope thats it

[Ronin 09]

Thanks Amaru, but it doesn't miss at idle. It doesn't do it continually either, seems to be an intermittent problem. May pull out the plugs again on Sat and see if they are clean or fouling.

Any other suggestions?

[GTS-t VSPEC]

Use BCP7ES plugs, there cheaper, and we use then on cars upto 600hp without any problems.

[Cubes]

Have you taken it for a decent drive?

My car was in getting sprayed for around 3 weeks without being started.

When starting it was a real pig to get going almost sending my battery flat.

I had to keep the rev's above 2000rpm other wise it would die in the arse.

It ran really rough with a type of miss.

10-15km's later it began to smooth out and returned to normal.

It was a pain in the arse at the traffic lights

I was told it was a leaky injector. Who knows.. It runs fine now.

I do get the occasionaly slight wanting to stall every other morning.

Get it a flick of the throttle and rev's come up and the car runs fine, if I don't it will sit there lumping over until it stalls.

[Ronin 09]

Okay, done about 250 kays since the panel shop, still using the iridiums.

We pulled out the plugs on Saturday, and all of them are perfect, no fouling.

The only time it misfires is when on boost, it idles fine, will happily rev out on partial throttle, however whenever under load it misses.

My feeling now is that it could be a number of things:

1. dodgy coil. Better plugs, maybe demand more from the coils, and hence only misfire under boost.

2. dodgy igniter? My guess however is that this would cause the car to misfire continually.

3. dirty AFMs. Would this cause misfire under load?

4. spark being blown out by boost. Iridium tips are very small, would the spark be too small and get blown out by boost?? I would have thought not, seeing that these plugs are only specified for GTRs and supercharged mercs

I may have to go back to coppers and try that

[Ronin 09]

hmm was just reading a thread RE surging... can someone define 'surging'

I wonder if what I describe as 'missing' is surging?

What I think of as 'missing' is when I floor it, the engine loses power, and just stutters but will still rev...

HELP!

[GUN R33]

I posted a thread about my car surging, and yes surging I mean missing. It runs perfect until I boost it anymore then about 9psi then I starts to shutter like a dog. I'm going to check the plugs tonight and regap them to 0.8 and check the coils for any cracks.

[666DAN]

I thought my last original coil pack died the other day, displayed the same symptoms you’re describing…this time it wasn’t the pack that had died, it was the connector on the loom. Just pushing slightly on it was enough for the missing to stop!!! I cut it off and replaced the spade terminals, and now it works fine.

It was very intermittent as the connector expanded on heating making the terminals…break contact now and again.

[Ronin 09]

Does anyone think that the Iridium plug electrodes are too small and the spark is blowing out on boost? B/c the copper electrodes are a dirty big lump of copper...

Will switch back to copper this weekend and see if that works

[GUN R33]

I checked my plugs tonight and found that one of my plugs white case was cracked, I hope that this is whats causing my car to miss!

[GTS500]

Hey i have seen this with the iridum plugs a number of times having replaced them with NGK bcp6es or 7es tends to solve the problem but if it continues try the spring conection between the coil and spark plug as corosion can build up and cause a problem.Good luck

[Ronin 09]

Hey i have seen this with the iridum plugs a number of times having replaced them with NGK bcp6es or 7es tends to solve the problem but  if it continues try the  spring conection between the coil and spark plug as corosion can build up and cause a problem.Good luck

Thanks GTS500, will give it a shot.

I have a feeling it may be coils on the way out too.

[Ronin 09]

For those of you who care, I installed a set of DI Splitfire coils tonight. Seems to have solved the problem, but still misses a tiny bit high up.

Might have fouled plugs driving around with dodgy coils for 2 weeks (too lazy to pull them out tonight and check), but will try some coppers on Sat - should be tip top by then.

[Col-GTSX]

I am currentlly having this problem... I put in iridium's last night and what do you know. Everything over 8-9psi it misses like a littch beatch....

How do you guys go... I used 5's as their a colder plug and worked really well in my old rb20 powered line.