BMC125

Specs JDM B16A, p30 chipped and tuned(unsure by whom),also have neptune. OK so about a month ago I was doing some spirited driving and noticed vtec was engaging super low about 4800.(try to stay outta it to save gas) also it would only rev to 7200. Car was at optimum temp. about 20 mins later still driving it was fine. Car was doing this for about 3 weeks and now just stays that way. I have checked wiring, switched ecus, also checked for vac leaks. My question is where else can I look too. HG possible? Or would the Hg be more sporadic. Any help is greatly appreciated. I have searched and found something but not the answers I'm looking for. Any other info needed let me know.

BMC125

Any help please? I'm getting desperate. I have asked everyone I know that knows anything Honda and they are stumped and help is much appreciated.

HondaPartsHero

What ECU did you switch it with?

BMC125

Stock p30 basemap on Neptune. The issue was before the swap and is still occurring. I should also state the car previously ran fine on the Neptune(before this issue had started.)

HondaPartsHero

Try an unchipped ecu that is known working

BMC125

I have done that. I have cleaned the vtec solenoid, checked the wiring, it has a pressure switch, all wiring is in tact, sprayed my intake to check for leaks, also sprayed everything vac related not seeing any leaks there, I'm completely at a loss. Not ruling your idea out but car engages vtec at 4,800 when it originally engaged at 5,500 and revved to 8,200, now it won't go passed 7,200. Of there's any other ideas I'd appreciate it.

furious94ls

If the car use to engage VTEC at 5500, and now it engages at 4800 it's an ECU/Tuning issue. I'm assuming there is no CEL on?

nealnanoHX

My Vtec on my LS Vtec is tuned to come on at 5000rpms. Could be the tune and the redline may be set at 7200.

BMC125

No cel. And my question is then if it were a tune issue I have swapped 3 ecus into the car with the same issue. It started out sporadic and would then come back to normal after driving about a half hour. But in about the passed month with 2 different ecus in it, still hasn't worked correctly. I get where your coming from about the tune ecu issue, but with it working sometimes and then totally quit makes me wonder. Could a head gasket do this? Bad vtec solenoid? Vac leak? Tps? Map? Car runs well, just want it to get back to normal.

BMC125

Also the ecu that is tuned is sitting in my back seat. I have Neptune with a basemap p30 loaded on it running the car which before the car started this it ran fine vtec was at 5,500 and red line was 8,200 on both ecus. This is also why I'm thinking it maybe elsewhere other than a tune and ecu. Thank you guys for your input every little bit helps.

Fliptard

Change your dizzy and try that. I had a bad one in my h22, and sometimes it would not let me go past a certain rpm.

furious94ls

First, check the timing before you do that. Take the cap off and see if there is a lot of red dust, when it gets really dusty in there it's a sign the dizzy is on it's way out. I'd check timing, oil level, and yes check to be sure all sensors are working correctly. It should be throwing a CEL. Another possibility is the alternator isnt running at full potential.

BMC125

Thanks furious and everyone else, I'll do some checking in the next couple days. It's finals week so I gotta study but I really appreciate any ideas or experiences you guys have shared.

92/00CXhatch

I have a Z6 motor that redlines at 6000 also at a loss of words with you. but ive changed my tps. iac valve. map sensor. plugs. ignition coil. changed ecus. new cap and rotor. so if you figure your problem out please let me know thanks.