Jump to content
SAU Community

Recommended Posts

Gday, over the last couple of months ive noticed a pretty bad misfire at and above 4k rpm, which it will always do. I noticed after driving for around 3 hours last week the misfire completely went away, only to come back later. I've tried changing the coilpacks which i beleived could have been the culprit though with changing 4 out to rb25 packs which were working fine prior to me receiving them, i cant get any combination of coil- on plug to eradicate my misfire. I have just removed all the coilppacks and plugs, and ive noticed 1,2,3 cyl experiencing yellow discolouration at the lowest part of the ceramic on NGK platinum plugs, less that 4000 ks old. 4,5,6 cyl plug seem in much better condition, though cyl 2 plug having experienced the worst of the lot, with the yellow looking more intense, resembling sunburn-orange at the lowest point. This leads me to believe cyl 2 must have had the worst of the misfire, with possible misses coming from 1 and 3, as those 3 coils have all had more heat delivered to the ceramic. Those coils have all been replaced, with all combinations of coil i have (10 in total) having been tried. I was running 14 psi with no issues for 3 years, and after noticing the misfire i have wound it back to the lowest possible, 12 psi, though it dosent make a difference 12, or 14. Up to 4000 rpm the car is fine, idles fine and no smoke. The issue could have originated around the time i originally changed the old plugs, which were iridiums. Anyone got any ideas to solve my misfire issue? Ta

Link to comment
https://www.sau.com.au/forums/topic/342475-rb20-misfire/
Share on other sites

I seem to have a similar problem. After i started boosting 1 bar ( Everything else stock except im using a Blitz ECU and 1 bar external wastegate), i used to have a jerk once in a while, especially on cooler days on full throttle when the wastegate opens. Initially i thought i had a fuel shortage and took it to the dyno but the fueling was good. The tuner recommended spark plug change, so i changed from Denso irridium power (did about 30k kms) to NGK irridium BKR8. It was ok for a while but i seem to have the same problem now. This morning it was raining and even at low rpms, the judders abit on throttle.

1. Are my plugs too cold?

2. Im using an NLTC (68 degrees) thermostat, because it gets really hot here in malaysia and if im stuck in traffic with the AC on, the temperatures goes up abit adn i thought i had overheating issues. After installing a water temp meter, i noticed my temperature doesnt rise above 70 degrees on normal cruising without the AC on. Is this too low for optimum ECU fuel mapping? i.e The ECU thinks the engine is still warming up burns richer?

Thanks!

Link to comment
https://www.sau.com.au/forums/topic/342475-rb20-misfire/#findComment-5525777
Share on other sites

Ok, i seem to have solved the issue. I ducked down to peps auto today and picked up 3 more platinum plugs, changed out the 3 discoloured plugs and tested that, and i still had the same issue. This lead me to beleive i have changed all that i could in that area, and the only other modification i could make would be to drop the gap on the plug down a bit, being 17 years old, the whole ignition system is getting tired and probably not delivering the energy to the plug that it needs to maintain spark, (changing to aftermarket coils could also help here). So i dropped the gap from 1.1 to around .8, possibly a little less. I also noticed a small crack in my breather cross pipe, linking the 2 rocker covers, which i cleaned a bit and duct taped it up best as i could. Anywho, started it up, gave it a bit and no problem, pulls to redline with no inkling of a misfire. I should probably look at swapping out and upgrading the coils though, im probably fighting a losing battle with these ones. Thanks for the help guys. Ta

Link to comment
https://www.sau.com.au/forums/topic/342475-rb20-misfire/#findComment-5525913
Share on other sites

Yeah changing spark plugs is the first step, and regapping them is the second. You might want to think about just going coppers mate, a lot of people here find platinums and iridiums don't last long enough to make the price worth it, and MANY have found they don't last much longer than coppers, if at all. I had a mate whose soarer used up iridiums in 3000km...

Glad the issue's fixed, misfires suck

Link to comment
https://www.sau.com.au/forums/topic/342475-rb20-misfire/#findComment-5527441
Share on other sites

Yeah i guess i should go for coppers too then. Any idea what heat range i should be looking at? Because now my NGKs are 8, according to the tuner, 8 is good, but according to everyone else, 6-7 is best. Im a little confused. I kinda suspect my coil packs might not be that good either. Any way to check this?

Btw, is my car being 'overcooled'

Also you could go yellow jacket coilpacks as well, they're a good bit cheaper and come with a 2 year warranty.
Link to comment
https://www.sau.com.au/forums/topic/342475-rb20-misfire/#findComment-5527910
Share on other sites

Oh ok thanks! Maybe ill try the 6, since im running 1 bar wastegate! If it is too cold, will it cause jerkiness on boost during cool days? I tried resetting my ECU as well yesterday, seemed smoother but still get jerk especially on gears 3-5.

Maybe too cold, 5 is okay for completely stock, 6 is good with some extra boost
Link to comment
https://www.sau.com.au/forums/topic/342475-rb20-misfire/#findComment-5528132
Share on other sites

Oh ok thanks! Maybe ill try the 6, since im running 1 bar wastegate! If it is too cold, will it cause jerkiness on boost during cool days? I tried resetting my ECU as well yesterday, seemed smoother but still get jerk especially on gears 3-5.

Hang on, do you mean you're running a 1 bar actuator? On a stock turbo? Do you have a boost controller? I'm guessing ecu is stock?

One bar is pretty high for a stock turbo, it'll eventually cause the ceramic turbine wheel to delaminate under high heat and rpm. If it's running 1 bar with no boost controller, it could be a leak in the factory boost controller lines.

If the plugs are too cold they foul as incomplete combustion material to land and stick to the plugs, if they're too hot they melt and die lol.

Link to comment
https://www.sau.com.au/forums/topic/342475-rb20-misfire/#findComment-5528169
Share on other sites

Sorry if i didnt give enough info, Im running a 1 bar external tial 38mm wastegate. ECU is blitz access, fuel pump walbro 255 and works fuel regulator set at about 37-38 psi. It was set at the dyno because initially it was too ruch at 40 psi. So my fuelling has no problems.

The jerks come normally at full throttle on a cooler/rainy day. According to the tuner, its because the fuel mixture becomes richer, hence harder to spark. whichis why i change my 30k km old denso plugs to the ngks. But after about 10k km, the problem seems to have come back. Could the coil packs be not in optimum condition. I will also try to open up the plugs this weekend to inspect the condition. When i changed the denso plugs, to my untrained eyes, it looked perfect (no fouling or overheating).

Hang on, do you mean you're running a 1 bar actuator? On a stock turbo? Do you have a boost controller? I'm guessing ecu is stock?

One bar is pretty high for a stock turbo, it'll eventually cause the ceramic turbine wheel to delaminate under high heat and rpm. If it's running 1 bar with no boost controller, it could be a leak in the factory boost controller lines.

If the plugs are too cold they foul as incomplete combustion material to land and stick to the plugs, if they're too hot they melt and die lol.

Link to comment
https://www.sau.com.au/forums/topic/342475-rb20-misfire/#findComment-5528388
Share on other sites

If the coilpacks are stock they're probably on their way out. What year and how old is the car? It's an easy upgrade to regain some slight power loss and rev-happiness from the tired old coilpacks. I'm not sure what effect those mods would have.

Usual rule is change sparkplugs for new ones, lower the gap, then change the coilpacks. Though you could just do all three, the coils will go eventually and will need the upgrade.

Link to comment
https://www.sau.com.au/forums/topic/342475-rb20-misfire/#findComment-5528393
Share on other sites

Well i guess the coil packs are as old as the engine. It was taken out of an R32 and transplanted into my cefiro.

Yeah maybe ill have the plugs inspected and gapped and see how it performes. The recommended gap is 0.7mm right?

If the coilpacks are stock they're probably on their way out. What year and how old is the car? It's an easy upgrade to regain some slight power loss and rev-happiness from the tired old coilpacks. I'm not sure what effect those mods would have.

Usual rule is change sparkplugs for new ones, lower the gap, then change the coilpacks. Though you could just do all three, the coils will go eventually and will need the upgrade.

Link to comment
https://www.sau.com.au/forums/topic/342475-rb20-misfire/#findComment-5528399
Share on other sites

Ok thanks for the info. Was running irridiums and they are really expensive here in malaysia. Changing them every 10-15k is really painful on the wallet!

Usually people go to 0.8mm first as you can buy the plugs in 0.8 (ngk bcpr6es, ngk bkr6es and bosch fr7dp (those are platinums, but cost like an extra 50c per plug than the ngk coppers, and might last 6000km rather than 5000km :) )).
Link to comment
https://www.sau.com.au/forums/topic/342475-rb20-misfire/#findComment-5528421
Share on other sites

I wouldn't bother using platinums, I have found that just using normal ngk's are better and are cheap as chips so you can afford to replacing them every service/6 months or whatever.

Also you cant regap iridiums, you will destroy the coating on them hence another reason why I wouldnt bother with them. Also if you start boosting it past standard you really should be running a .8 to .9 gap anyways (think the iridiums are only 1.1?).

Link to comment
https://www.sau.com.au/forums/topic/342475-rb20-misfire/#findComment-5528438
Share on other sites

yes put the stock temp thermostat back in. that will help.

and heat range 8 plugs are way too cold for what you are running. your problem is more than likely caused by the plugs fouling up, which is why you notice it more on cold wet days. go to a heat range 6 plug and you should notice a big improvement in how the car drives. it will idle smoother.

Link to comment
https://www.sau.com.au/forums/topic/342475-rb20-misfire/#findComment-5529667
Share on other sites

Thanks fro the tip bro, i shall try out copper plugs and removingt he thermostat first. And yes, my idle is quite rough once the car has warmed up and i do get some fuel smell from the exhaust. Hope the coil packs are ok. I dont wanna spend to much on this motor as im planning to swap a 25 hopefully next year.

yes put the stock temp thermostat back in. that will help.

and heat range 8 plugs are way too cold for what you are running. your problem is more than likely caused by the plugs fouling up, which is why you notice it more on cold wet days. go to a heat range 6 plug and you should notice a big improvement in how the car drives. it will idle smoother.

Link to comment
https://www.sau.com.au/forums/topic/342475-rb20-misfire/#findComment-5529819
Share on other sites

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

    • Thanks for all the replies fellas. Gonna finish putting it back together and see how it handles the set up. If it starts pinging it’ll be parked.
    • Well, I can recommend the partial AV system translation CD I ordered from Car Audio Workshop in NZ. Whilst it didn't address the date issue, it has conveniently translated on-screen menu items into English, and now allows the GPS-received time to be offset in hours rather than minutes, so I can display Eastern Australian time accurately ( and bump it by another hour when daylight savings starts ).
    • Yuh, if it's 45°C outside, my car is driving in it.
    • I'd be curious to hear more. Otherwise, have you driven a modern x-trail? I wonder how it compares. Here in Australia they are/were popular for rentals and fleet vehicles. I have been in some and my impression was they are bad. But, this may have been very different in the 2000s at a good trim level. Twenty years is plenty of time to make the model worse. I do very much agree with the 2 silver cars in the garage approach. But, not driving because it's too hot would not leave a lot of time in the year for many Australians. I don't think you need to worry too much unless the car has actual issues with overheating. 
    • Back again. I returned to Japan in Jul/Aug to spend time with the car on my birthday and remind myself what all the sacrifice and compromise is for. It happened to line up with the monthly morning meet in Okutama, which I have been wanting to go to for a long time. It's a unique event at a unique spot with really rare, interesting, and quirky cars. It's where all the oldheads and OGs gather. The nighttime scene at DKF certainly has its place and should be experienced if you're into cars, but there's too much bad attention and negativity around it now. IMO the better time is Sunday morning at DKF or Okutama; it's more chill and relaxed. I'm glad I was finally able to go, but not sure it's worth the drive from all the way from Nagoya immediately the day before, unless I was already staying in Tokyo for the days right before the meet, because you have to wake up quite early to make it in time. Funnily enough though I didn't drive the car all that much this trip because it was just too damn hot. While there were zero issues and running temps were nominal and the A/C was strong, RBs already run crazy hot as it is. Sure, it took it all like a champ but something about driving these cars in the ridiculous heat/humidity bothers me and makes me feel like I'm asking too much of it. I'm just me being weird and treating the car like a living thing with feelings; I'm mechanically sympathetic to a fault. Instead I was mainly driving something else around - a KX4(silver) 2001 X-Trail GT, that I acquired in May. There's a few different flavors to choose from with Xs, but visually it's the Nissan version of the Honda CR-V. Mechanically it's a whole different story as this, being the top-trim GT, has an SR20VET mated to a four-speed auto and full-time AWD! It was a very affordable buy in exceptional condition inside and out, with very low mileage...only 48k kms. Most likely it was owned by an older person who kept it garaged and well-maintained, so I'm really happy with how it all worked out. It literally needs zero attention at the moment, albeit except for some minor visual touch-ups. I wanted something quirky, interesting, and practical and for sure it handily delivers on all three of those aspects. I was immediately able to utilize the cargo and passenger capacity to its full extent. It's a lot of fun to drive and is quite punchy through 1st and 2nd. It's very unassuming -in the twisty bits it's a lot more composed than one would think at a glance- and it'll be even better once I get better tires on it(yes, it's an SUV but still a little boat-y for my liking). So...now I have two golden-era Nissans in silver. One sports car and one that does everything else; the perfect two-car solution I think👍 The rest of the trip...I was able to turn my stressed brain off and enjoy it, although I didn't quite get to do as much as I thought. I did some interesting things, met some interesting people, and happened into some interesting situations however, that's all for another post though only if people really want to know. Project-wise, I went back to Mine's again to discuss more plans and am hoping to wrap that up real soon; keep watching this space if that interests you. Additionally, while working in the tormenting sweatbox that is the warehouse, I was able to organize most of the myriad of parts that my friend is storing for me along with the cars, and the 34 has a nice little spot carved out for it: And since it can get so stupid hot in there, that made it all the more easy -after I was standing there looking at the car and said 'f**k it'- to finally remove all the damn gauges that have mostly been an eyesore all this time. Huzzah. The heat basically makes the adhesive backing on the gauge mounts more pliable to work with, so it was far less stressful getting this done. I didn't fully clean it up or chase the wiring though; that will happen once I have the car in closer possession. Another major reason to remove all that stuff is to give people less reasons to get in my car and steal s**t while it's being exported/imported when/if the time comes, which leads us to my next point... ...and that is even though it's time in Japan is technically almost up since it's a November car and the X would be coming in March, I'm still not entirely sure where my life and career is headed; I don't really know what the future looks like and where I'm going to end up. I feel there's a great deal of uncertainty with me and as a result of that, it feels like I'm at a crossroads moreso now than any point in my life thus far and there are some choices I need to make. Yes, I've had some years to consider things and prepare myself, however too much has happened in that time to maintain confidence and everything feels so up in the air; tenuous one might say. Simply put, there's just too much nonsense going on right now from multiple vectors. Admittedly, I'm struggling to stay in the game and keep my eyes on the prize. So much so in fact, that very recently I came the closest I ever have before to calling it quits outright; selling everything and moving on and not looking back. The astute among you will pick up on key subtext within this paragraph. In the meantime I've still managed to slowly acquire some final bits for the car, but it feels nice knowing there's not much left to get and I'm almost across that finish line; I have almost everything I'll ever want for my interpretation and expression on what it is I think an R34 should be. 'til later.
×
×
  • Create New...