Engine runs on 2 cylinders. Number #2 and #4 give visibly weaker spark. Swapped the coils around, no change, the fault stayed with the plugs. Those faulty two also have bright, clear tips instead of covered in soot/carbon, but I don't know if this is a smyptom or part of the cause. They also smell like gas. Plug gap is exactly the same between a strong and weak one, so I don't think material is missing from either electrode.
Iridiums, BCPR 7 EIX
-4 years: bought them new from ebay,some time before fakes started to appear in large quantities. Upon receiving them, they looked authentic according to NGK's fake spotting guide
-3 years: put them in, went ok with 1 bar of boost
-6 months: BHG started, put the car away
-6 weeks: car still started up completely normal after zero activity during the winter, with battery left in and connected
-3 weeks: tried to start it, but battery was drained completely for no apparent reason
-2 weeks: battery charged, cranking OK, but engine is running on 2 cyls
-1 week : every troubleshooting scenario in the FSM related to fuel or ignition turned out OK

Does anyone have an idea about what could have happened to them? Do these just "die"?

They're fouled out. You're SUPER rich. Because of the carbon, the electricity has a path to ground once they get a little fuel/moisture on them and fail to spark properly. They're basically done and you need to replace them.

I would get some cheap NGK coppers, BCPR6ES-11 (unless you're running a lot of boost, you don't need 7 heat range plugs) until you figure out the over-fueling issue so you're not wasting money on fouling out those iridiums.

Since I mentioned it. I see WAAY too many people switch to 7 heat range plugs IMHO. I ran BCPR6ES-11 at 15psi on a CA T25 for YEARS without any issues. I ended up switching to the Iridiums, but I still stayed with a 6 heat range.

float_6969 wrote:They're fouled out. You're SUPER rich. Because of the carbon, the electricity has a path to ground once they get a little fuel/moisture on them and fail to spark properly. They're basically done and you need to replace them.

I would get some cheap NGK coppers, BCPR6ES-11 (unless you're running a lot of boost, you don't need 7 heat range plugs) until you figure out the over-fueling issue so you're not wasting money on fouling out those iridiums.

Since I mentioned it. I see WAAY too many people switch to 6 heat range plugs IMHO. I ran BCPR6ES-11 at 15psi on a CA T25 for YEARS without any issues. I ended up switching to the Iridiums, but I still stayed with a 6 heat range.

You're also running E85, IIRC, that changes things considerably, I think, but thanks for the tip all the same!

What constitutes "super" rich, and overfuelling? Because I'm tuned to ~12-ish in boost. Right side "gauge" is AFR here. Straight up is 15, 1 division = 1 point. Wideband itself an LC-1.

Cruising is in closed loop, it's hunting for 14.7.

I was planning high boost, that's what the higher heat range is for (7 is actually still a stock recommendation, that's why I've switched to them even at this low boost). I'm stuck at 1 bar for various reasons, but that 1 bar comes from a HX35. That is more air, than what a GT2560R puts out at 1.3bar, this, I have firsthand experience with.

I ran the Iridiums both before and after the E85 switch. Regardless, a fouled plug doesn't care what fuel was used. That kind of fouling only comes from too much fuel/poor fuel atomization.

When is the last time you calibrated the LC-1? I've owned 3 of them and I know they can get out of calibration. I don't know what you're using for tuning, but maybe it's screwing up your LTFT's and making the engine run rich, even though it shows the AFR'S are OK.

12's in boost shouldn't foul plugs, and the 14.7 swing is normal.

My only other idea is that maybe there is a bad ground(s)/failing ignitor. That could cause a weak spark and might show up as fouled plugs from incomplete/delayed combustion.

float_6969 wrote:I ran the Iridiums both before and after the E85 switch. Regardless, a fouled plug doesn't care what fuel was used. That kind of fouling only comes from too much fuel/poor fuel atomization.

When is the last time you calibrated the LC-1? I've owned 3 of them and I know they can get out of calibration. I don't know what you're using for tuning, but maybe it's screwing up your LTFT's and making the engine run rich, even though it shows the AFR'S are OK.

12's in boost shouldn't foul plugs, and the 14.7 swing is normal.

My only other idea is that maybe there is a bad ground(s)/failing ignitor. That could cause a weak spark and might show up as fouled plugs from incomplete/delayed combustion.

Last time I calibrated the LC-1 was maybe 1.5 year ago, but that was only about 500 miles ago, and even then, nothing changed at all. Anyway, I guess it's worth a try.
A ROM tuned stock ECU is running the show.
I've checked the coil grounds when I did the troubleshooting, it was some 0.1 ohms coil plugs to intake manifold. I haven't tried it to the battery terminal, as that one's in the back.
Weak coils maybe? Does that happen? They're still the stock ones, but I've decided to wire in one of my LS2 sets before doing anything else. It's high time to replace these weak 25 year old ones with a fresh, young 12 year old set, and I've finally just got timing light, too.

Today, I've went on to check some grounds, and plan the coil conversion, and while dismounting the coil holder plate, the ground wire that is screwed onto this plate snapped off, quite easily. The wire strands are almost completely corroded. It probably wasn't a very good ground source for the coils, despite measuring good ground continuity to the coil plugs. That gets a fresh wire next weekend as well.

I usually check grounds back to the battery, but as long as you have the big ground wire from the manifold to the body in place, you should be fine there.

Exhaust leak? Clean air getting into the exhaust pipe and spoofing the sensor? This would be especially likely if the engine was tuned WITH the exhaust leak.

Wideband O2 sensors do degrade over time and need to be recalibrated as they age. Innovate recommends every 500 miles iirc so It's worth a shot.

there's a few reasons why the plugs fouled up:
-too rich AFR
-bad coil packs
-plugs too cold


I have seen way way too many people slap colder plugs into their engine, regardless of which car, simply because they turned up the boost a few pounds or put a bunch of power enhancing bolt ons to their car... it doesn't make things better, it usually makes things worse!!! The stock heat range plugs will go a long way before you start getting preignition issues, which is the real reason why you want to go to colder plugs... believe it or not, most people don't even know why there's a reason to go to colder plugs in the first place! They just follow the guy who have a super fast car boosting 25psi while they're putting around with only half that!

Would you not recommend going from a 6 heat range plug to a 7 range plug to help with minor pinging?

My car has all bolt ons and is running a mines ecu (with very slighty retarded timing ~13 degrees btdc) and spikes to 16psi and holds 15psi. This is on a rebuilt S14 T28.

The car did make 266rwhp on 18psi dropping to 16psi on the dyno, but there didn't seem to be pinging. This was also on 15btdc ignition timing. Timing, i know should be at 10 degrees for JDM. I guess the car was set to 15btdc when it was on the dyno. The minute real load was applied it was quite audibly pinging. Also the idle is rough, which i should adjust when on 10 degrees, but that extra 3 degrees makes the car a touch more snappy and it also idles better.

I have dropped the boost and retarded the timing slightly. I am now planning on going to a heat range 7 (BCPR7ES from BCPR6ES). The pinging is light.

I drive the car to work every day and the car gets to proper operating temp so i am under the impression that from using a 7 heat range plug will foul up easier specifically for short drives too as the plug tip does not burn the fuel effciently as it doesn't get to operating temp?
Also with the 7 range spark plug, going from a 6 - will it not cool the cylinder temp down by up to around 100 degrees Celsius? which can help reduce detonation?

I would put the timing back to the 10° and see if the pinging is still present under load. If it is, THEN try the colder plugs. I would be willing to bet that extra 3° is contributing to issue. From my experience, this motor is picky about timing, and it doesn't handle too much advance very well, especially the 8 port heads.

When running a chipped ecu, you will likely foul plugs quickly with a colder plug. They tend to let the engine run VERY rich in the top end to fight detonation. Going to a colder plug will cause it to foul quickly. Those chipped ecu's also tend to be a bit aggressive with timing advance IMHO, and so advancing the base timing even more is a BAD idea IMHO.

All of that being said, a colder plug does drop the cylinder temp by 70°-100°C, and can help with the pinging, but I would do that last.

Also, retarded timing and colder plugs are REALLY a symptom of fuel that lacks the octane rating for the engine. If you want to keep the benefits of the advanced timing and the self cleaning abilities of the colder plug, I would put water injection on the engine, or switch to E85. Either option will allow for the most power, with the best reliability.... or run less boost, but who wants to do that!?!?! LOL

float_6969 wrote:I would put the timing back to the 10° and see if the pinging is still present under load. If it is, THEN try the colder plugs. I would be willing to bet that extra 3° is contributing to issue. From my experience, this motor is picky about timing, and it doesn't handle too much advance very well, especially the 8 port heads.

When running a chipped ecu, you will likely foul plugs quickly with a colder plug. They tend to let the engine run VERY rich in the top end to fight detonation. Going to a colder plug will cause it to foul quickly. Those chipped ecu's also tend to be a bit aggressive with timing advance IMHO, and so advancing the base timing even more is a BAD idea IMHO.

All of that being said, a colder plug does drop the cylinder temp by 70°-100°C, and can help with the pinging, but I would do that last.

Also, retarded timing and colder plugs are REALLY a symptom of fuel that lacks the octane rating for the engine. If you want to keep the benefits of the advanced timing and the self cleaning abilities of the colder plug, I would put water injection on the engine, or switch to E85. Either option will allow for the most power, with the best reliability.... or run less boost, but who wants to do that!?!?! LOL

I can always rely on Nico club for an honest, educated answer.

Thanks Heaps Float. I will retard timing to 10 degrees and see how the car goes.

No problem, glad to help! Keep us posted on what changing the base timing back down to 10° does.

An update, the car intermittently pings. Which leads me to believe that fuel quality may differ from different gas stations here in Sydney.

I have not yet retarded the timing yet, mainly cause i don't have a timing light, but i may just turn the CAS ever so slightly.

So, I have chucked the stock coils, wired in the LS2 coils, bypassed the igniter, changed the spark plugs, and continuity checked all the wiring almost end to end. Started the engine. It started. But it is still running on 2 cylinders.

Now it can't really be ignition related. Then, maybe sticking injectors, or shorted/blown injector drivers in the ECU. I may be able to test for that from the outside, but I thought I'll open up the ECU first, maybe there's some obvious visible damage, and I don't need to spend half a day investigating the issue.



Well, I don't need to spend any more time investigating the issue. I'm willing to bet big money, that those are #2 and #4 injector drivers. Two capacitor leads have corroded away into nothing, I'll replace them, clean the whole thing up, inspect it, and give it another go.

That looks like it had standing water in it. Is the ECU in the engine bay?

float_6969 wrote:That looks like it had standing water in it. Is the ECU in the engine bay?

It definitely had standing water in it, that sludge is made of rust and salt. Although the ECU is inside the car, it wasn't screwed back into place, just stood on the carpet on that corner, and also leaning a bit sideways. Since I don't have any traces of water drips or flows inside the chassis (though my right carpet is always a bit damp), I'm guessing this was "just" condensation, that couldn't get out like it was supposed to, around the harness connector area, for example.

Most of the sludge actually cleaned away nice with a couple of strokes from a toothbrush, it's looking better now.

That ecu looks wasted.

Can you source a working one, plug it in and see if the injectors work? All 4 of them?

Working in the spa business, you would be REALLY surprised the amount of moisture/water a circuit board can tolerate. If there is no obviously burned traces, you can often clean off the corrosion/scale and everything will work just as it did before.

float_6969 wrote:Working in the spa business, you would be REALLY surprised the amount of moisture/water a circuit board can tolerate. If there is no obviously burned traces, you can often clean off the corrosion/scale and everything will work just as it did before.

I believe you when you say that Float.

Just to be sure, i think its a good idea to isolate that the ecu is not fully functioning.

Pulled the timing back and the pinging has stopped. The car can take more boost. now at 16-17 psi.

Now clutch is on the way out!