S2 RB25 problems

[rastamon]

Started up and has been running about a month now but never running right. It cranks, idles, and runs good if your goal is fuel economy. Trying to accelerate to fast causes coughing, missfires, and backfire problem, mostly 3rd gear and higher. Best way to explain how much trying to accelerate causes the problem I would say is about 30% pedal. Have no major mods and stock boost. Started off going from NGK BKR5ES-11's to BKR6ES and coating my coils with liquid tape. Ive ran Lucas injector cleaner multiple times. I wasn't to confident in the OEM alternator so I did a switch to the Quest 125Amp. So the finale is today I gaped the BKR6ES's down to .80mm and it will crank but feathering the gas pedal is necessary to keep it running. :picardfp:

[AS240]

maybe a bad maf of tps? you you have an intake, exhaust or anything like that? and are you still running the stock ecu?

[BigPawr]

This is pretty much a problem that has existed since people started swapping RB25s. I had this issue 5-6 years ago with my S2 RB25 swapped S14. I never resolved the issue and sold the car (not becuase of the issue). I've read over a million threads on people with this issue. People say plugs, maf, coils, timing, stock ecu doing things, etc... There really is no anwser I've ever read to resolve this. People will swap out their mafs, coils, plugs, etc and randomly every now and then one of those things will "solve" the problem. I have never read a detailed consistent answer to this problem. Really your only choice is to go EMS, or maybe aftermarket coils as thats what most people lean towards thinking the issue is.

And just to show you how notorious the problem is, thread for exact same issue started recently on 2/14/12 http://zilvia.net/f/engine-tech/435755-rb25-missing-higher-rpms-done-lot-research.html

He said a maf solved his issue. But I have a hard time believing this problem exists so wide spread among people and its bad mafs.

[Sileighty_85]

get some NGK 7's coppers, gap them down .028inch.