Beckerton

I have a B16A in my EG Hatch. Today when I was driving the car it engaged VTEC and was pulling through the RPM, when it hit 7000RPM it made this very loud "opening" type sound...Almost as if secondaries or a second stage of VTEC kicked in...I don't know what it was, I'm not suggesting it was a good thing, but I backed off the throttle as soon as I heard it. I then took off and ran the car through the RPM's again and it cracked at 7000RPM again...I almost thought my silicone coupler @ the throttle body had come off and my car was running right from the throttle body. I checked under the hood, there are no cracks in the coupler, manifold, air intake piping or any other things I can visibly see. The car has clean synthetic oil in it approximately 1200kms old...which is somewhere in the neighbourhood of 700miles. It happened those two times back to back and hasn't happened since. Has anybody ever had this happen to them or know what it could be?

Beckerton

Come on guys, I'm open to any insight...I don't want to drive the car if something is ready to let loose...

RICKSAUTOMOTIVE

just a guess, but maybe you floated the valves. this would fore air out the intake valves (and fuel too) so it would sound like a little back fire i would guess if the plugs ignited the mix (not sure with no compression). but possibly the air coming back out created a louder sound in the intake. we would have to hear it ourselves i guess for a better opinion

Koopa Troopa

I used to get a loud vibration at high RPM's with one of my old B16A's that could be similar to what you're hearing but it was more metallic sounding. An exhaust bolt was a little loose and would vibrate excessively at high engine speeds causing the sound...

I dunno, unless you post a video I don't think any of us can give good advice.

$kreech

i highly doubt u would float valves at 7000 rpm. maybe 8200+ if your b16a valve springs are stock, or a wack brand if they're replaced.
post a video for more insight.

$kreech

just a few questions 2 c if i can help, wat type of intake are u using, stock, short ram/cold air intake? also is your ecu stock, or have u changed it recently since this problem has developed?

random-knight

ahhhh thats just vtec kicking in ahaha

RICKSAUTOMOTIVE

LOL yeah i love that sound guess he dont know what that sounds like LOL i thought it was an actual problem but its probably the vtec LOL

$kreech

yep it could be this is where the v-tec engages but onli if he has in a chipped/aftermarket ecu.... still waiting on your response op

Beckerton

It's not VTEC engaging! I'm not stupid enough to set my VTEC engagement at 7000RPM. The ecu is chipped with a B16A basemap on it because when I bought the car it came with an unknown map on the chip. When I pulled the values from that chip it was very similar to a D Series VTEC fuel map...The car has driven fine on this B16 map and this was the only time I have heard the car do this. It hasn't happened since so I do not have a video of it occuring.

I was thinking something along these lines, I really hope not...Even though I have to agree with others, floating valves at 7000RPM seems a little odd. I'm thinking that it could be valve related though. Intake is a short ram by description, although it is longer than most short rams I have seen, I suppose it still is drawing in engine bay air. Is it possible that I somehow jumped a tooth on the intake cam only? The car didn't bog, or run sluggish, just made a stupid loud sound at 7000RPM that is best described as the intake getting louder. It still pulled smoothly. In the 1600kms I have put on the car since putting it on the road, it has not done this until the other day.

Beckerton

Well I'm bringing this back from the dead...Car did the same thing twice tonight...Once on my way to work, the other about 4 hours later on my way home. The car doesn't bog or anything, the intake just gets loud. With my chipped ecu hooked up to my laptop (Crome Pro) the car shows that VTEC is working, but this is what I was wondering...

Maybe the spool valve needs to be replaced or perhaps there is a blockage in one of the oil orifices somewhere. From my understanding VTEC operates both electronically and from oil pressure. That's why you can set when you want VTEC to engage and it won't engage until then. So maybe the ecu is sending the signal to the VTEC solenoid (spool valve) but the solenoid isn't getting the electrical signal. Maybe this loud intake noise is VTEC actually engaging at 7000RPM because of a shitty electrical connection. Perhaps the intake sound wouldn't seem so loud if VTEC engaged where it was supposed to and sound increased with RPM as opposed to me running through the RPMs and then the car switching cam profiles at 7 Grand.

Any clue how I can test to see if the valve is getting electrical signal? Any other suggestions or even facts to discredit my assumptions?

Slacker93eg

Are you 100% it's the intake? Could it be under such high rpm the exhaust studs are coming loose enough to let it escape right before the header? Just a thought

Beckerton

I am almost positive the exhaust studs are not "coming loose". If they came loose I would notice the exhaust leak. It is an intermittent problem that only occurs between 6000-7800 RPM. It is the intake as far as I can tell and it gets really loud. I would shoot a video of it but I cannot make it occur, it is entirely random and intermittent.

Beckerton

no help?

random-knight

hmmm what model is the wiring harness? do you know if the vtec was wired into it, or was it and harness with vtec already? I'm thinking that if it was vtec maybe theres a lose wire or something not connected right...