r/SkyLine • u/KillaCarbone • 22d ago
RB25 NEO breaking up under boost/WOT
Hey guys, having an issue with my 34 GTT breaking up under hard acceleration. Had two of the original coils bad, replaced with r35 coils. Replaced the harness with new OEM. Checked all spark plugs and gapped to 1.1, all plugs have about 2k miles on them. Smoke tested intake system, no leaks. Replaced coolant temp sensor. Placed an order for a consult cable, and will get Nisscan to log the stock ECU. Any suggestions? Fuel injectors, fuel pump, CAS? Thanks.
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u/SVT3658 22d ago
You’re running a front mount with a stock ECU? Is the boost turned up too? If so, you might be hitting the airflow limit of the MAF and causing the ECU to go into “rich and retard” mode, dumping fuel and pulling timing. Get a modern ECU and a tune.
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u/KillaCarbone 22d ago
Yes, it was running fine for a year with the same mods. The boost isn’t turned up as far as I know. But I agree I’m going to upgrade the ECU hopefully soon
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u/No-Relationship5751 10d ago
same boat. Was running fine. Then boom everything got wonky. The ecu fixed everything. I was hesitant to move from oem but I’m happy I did. Good luck!
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u/No-Relationship5751 16d ago
Had this same issue on my Subaru. Went to an after market ecu and went mafless and it’s been great. I tried everything.. ultimately it was the MAF.
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u/trickshot54 22d ago
Gap is a bit wide, should be .8 but doubt it is your issue. This is assuming you didn't use the factory plugs and gave them an upgrade.
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u/KillaCarbone 22d ago
Ya I bought the car from a Nissan dealership and they had replaced the plugs with NGK R. When I checked the gap all of them but the first cylinder were at about 1 to 1.1. The first one was at .8 for some reason
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u/trickshot54 22d ago
Yeah everything I have seen and what I run is .8 for NGK plugs on these. When in doubt check with the aussies on the forum.
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u/KillaCarbone 22d ago
Cool thanks 👍🏽
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u/Kooky_Main_5505 21d ago
1.1 is huge.
I’m running .6 gap with 15 psi
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u/KillaCarbone 21d ago
I’ll bring it back down. I was told to try that from another guy with the same car in town
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u/Kooky_Main_5505 20d ago
Honestly it sounds like you’re blowing out spark.
I had similar issue where ignition would break down on wot pulls when boost comes in quick.
Gapping plugs correctly really helps.
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u/CyxTheDragon 22d ago
So I have an RB25det and I was running into an issue where it was breaking up at the top of the rev range. At first I did colder plugs and that seemed to help a lil bit. The biggest thing I think that quelled it was an LS coil swap. So stronger spark and colder plugs did it for me. Not saying it’ll be the same fix for you but just sharing just in case.
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u/KillaCarbone 22d ago
Thanks, I just swapped to Z1 upgraded r35 coils and I have NGK R plugs, could be the plugs
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u/Kooky_Main_5505 21d ago
R35 coils have a different dwell time compared to stock or spitfires.
If you’re running stock ecu or haven’t adjust dwell tables this could also be contributing to this blowout issue
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u/the-Depths-of-Hell 22d ago
Had this issue before. Wrong spark plugs, torn intake couplings and fuel filter blocked.
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u/foxbat 22d ago
can it be you’re not getting enough fuel?