Well if everything is obviously wrong at VTEC engagement then I would be looking there for clues.

Is VTEC actually engaging - compare another car?

Is the temperature guage reading normally and engine actually up to temperature okay?

Check the fuel pressure at the rails.

Check for air leaks on the intake side - fast idle and squirt everything with WD40, you know how.

It could be that simple. A big air leak = lean burn = misfire and CEL at high revs....

MB - any knock sensor showing up as a dedicated code in this ECU? Or will it simply appear as a misfire?

 

i know what vtec feels like in general - had the 2.2 vtec '95 prelude before this car, but i've never been able to compare my s2000 with another one.

if anyone is willing to take me out in theirs, then im based arond coventry, east birmingham and oxford are my main 3areas... (covnetry home town, oxford at weekends)

air leaks seem to be fine.revs up at idle perfect, not been under bonnet and reved up though.

 

I'm down in Hinckley on Sunday & wouldn't mind taking you out for a quick blast (as long as it aint too wet )

Only thing is mine's an 04 and the VTEC is smoothed out quite bit compared to MY00

 

ok.........
this morning i've had ECU apart -pins are as new, as are the electronics inside it. nothing blown, and nothing corroded.

fault code (using blink codes - shorting pin1 to ground), is again on cyl 1 only this time. thats with swapping injectors 1>2, 3>4 last night

checked vtec solenoid - the oil plunger is free. havent checked the actuating solenoid yet - need an AVO for that.

cam cover off - cams appear fine, ran a 2p over them laterally and no scoring as lack of oil would cause.

something around vtec is actuating... but i dont know what - either the vtec fuel map, or the vtec cams. not both hence the lack of power&CEL light.

temp guage is fine - 3bars exactly 50% way up the guage. doesnt move from there when warm. doesnt warm up to fast or too cold either.

me off out to grab some WD40, and maybe el-cheapo avo to check continuity of the vtec solenoid...

really running out of things to check now, i cant see it being the engine because it's perfect outside of vtec. thus compression, valves etc should all be fine. no fluid contamination either in oil/coolant.

last thing todo now is drop some of that tesco99 in it... not one around coventry, but there is one in abingdon which is where im currently at. (ran 95, now running 97 and stil the same)

i'll drop you a PM later today siCr. arrange somewhere to meet im available anytime sunday really..

 

got an afr gauge?

get it on when driving, if it's just plain lack of fuel at high rpm it should show as running lean

 

afr guage? never heard of one. interesting though. just done a bit of lookup on it and it's basically the same as what an MOT test stationhas for emmisions. i do have MOT test station kit available.

and boy do i feel silly. just stuck some tesco99 in,and im actually getting vtec and noticably more power!
obviously95 isto low.moved to 97ron and still no luck - same as 95 fuel. 99 is running alot better going to let engine cool down, reset ecu so it can re-learn the fuel ocane then test it out again! looking good. cant beleive it's looking like a fuel issue.
least i've gained a map sensor an spark plugs as spares

next thing im going to look at is a re-map to get it to run ok on 95/97 fuel rather than having to source the rarer ~100 octane fuel! nearest station to me is a shell garage that does the v-power and is a 20-30mile round trip. good excuse for a drive, but a bit far togo every time i need a refill

 

tesco99 fuel is noticably better now. alot better now. but still getting CEL light coming on. just put some octane booster fluid in and no difference.
still the same - cyl1 but no-where near asmuch power loss as when i was running on unleaded/super unleaded fuel.

no mods have ben performed in japan - car was for JDM, but came straight over hear as a new car (alarm certificate dated april 2000)

i know there was a grounding issue on some s2k's, so i've fitted an earth strap. from just infront of cyl1, direct to battery cable bolt on the bulkhead - no difference.

sicr - ygpm

 

Can't be arsed to read all the thread

Is yours a JDM import?

 

yep, jap import. build there, came straight over here for 1st registration i know what you mean about the thread - it is a bit lengthy.

new plugs, new map sensor, swaped injectors 1-2, 3-4, same with coil packs, added new engine earth cable, checked vtec solenoid, vtec solenoid gause not blocked, cam cover off and checked cams arent worn with 2p peice

car runs fine outside vtec engagement, once it gets into vtec it feels like hesitation/mild misfire. car is noticeably better running tesco99 fuel. even girlfriend has said so too - very noticable improvement.
idles perfect and pulls perfect untill 6k rpm when CEL light comes on and feels hesitant.

fault codes have been coming up as p0301 and p0303 (cyl 1+3 misfires) on code reader, this weekend i've been using blink codes and just been reporting 7-1 blink, which is cyl1 misfire (same as p0301 dtc). dont know if this is limitation on blink code memory, or if cyl3 is fixed.

 

And it goes when you put higher RON fuel in!
How weird!
Have you tried Octane booster with 95RON
If that clears it surely it can only be the ECU struggling with timing on the lower RON
Have you had it from a while?
Have you ever put lower RON in before?