[cuzzybubba1]

That's some seriously funky s***! Get it checked out A.S.A.P!

 

[Eric.]

Maybe Sunoco doesn't have much VTEC additive so you need to add VTEC fluid yourself. I'd try the dealership first.

 

[Taff7Si]

Update: took it to the dealership, when they replicated the problem firsthand, it actually got worse for some reason! the CEL came on, and the engine was sputtering in and out even at 3k rpm mg: which made the car totally undriveable, vs. just not being able to hit 8k rpm on WOT beforehand.

They're not sure what it is yet, but they got some handy guys on it (thanks Lester and Kevin +rep :wavey. They will replace the MAF sensor, as recommended by Honda Canada and see what happens (hopefully that's the culprit). Honda Canada is giving me a rental for the time being until the car is repaired :cheerleader:

p.s. I have a Canadian Si, 2007, which does not have VSA.

 

[cuzzybubba1]

Good luck man! Let us know what they find out.

 

[infiniti_4_life]

You should have kept it @ 7K for a longer period of time in your video so we can clearly see/hear the fuel cut off @ 7K.

 

[Taff7Si]

True... Not that you can see much (but at least you can hear), I uploaded a couple more vids from a few days ago:

YouTube - MOV00005

YouTube - MOV00006

 

[41954]

i just discovered the problem today.. except the limit was like 6k. ughhhh

 

[41954]

Alright i got it fixed at the dealer today. It turns out the part of the intake hose that goes to the fender collapses at WOT.

They replaced it with a new one and it pulls like a mother. :dance:

 

[GlassFabs]

When you say "fully warmed up", do you mean you started the car and let it idle until the temp gauge was showing the "normal" operating temp? If that is the case, then chances are the car internals were not fully warmed up. I saw this happen to another guy. He warmed up the car in the driveway and took off, but the ECU was still reading a cold engine so it limits his RPM's. However, in his, he hit the earlier limiter in 1st gear as well.

Interesting. As someone else already wrote, you probably confused the ECU so it jumped into safe mode until it figured out what was going on.

**Note: I just read the rest of the post. Nevermind

 

[Taff7Si]

Alright i got it fixed at the dealer today. It turns out the part of the intake hose that goes to the fender collapses at WOT.

They replaced it with a new one and it pulls like a mother. :dance:

Is your car stock? did the problem only come up when you are in gear or when in neutral and reving too?

 

[41954]

Is your car stock? did the problem only come up when you are in gear or when in neutral and reving too?

Yes it is stock. And i didnt try revving in neutral so idk. It occured in any gear at WOT. Do you have an 09 btw?

 

[Taff7Si]

Alrighty, the results are in!

gaaawdaayum, turns out my 2007 has the same problem as RSaLan! after a few days of guessing, and reading your post, my problem is also traced to the rubber intake nozzle at the fender (see part 13 below).

A 3D model of the engine+intake for illustrative purposes:

In real life, it looks like this (i stole this pic from someone else on the 8th also :dance

For some reason, under WOT, the intake is creating so much negative gauge pressure inside the nozzle that it actually collapses the rubber part, thus choking the engine, causing the previously mentioned symptoms.

I'm currently driving w/o this rubber part, and the car now revs fine under WOT once again. The only diff is that I notice the VTEC 'growl' is not as prominent as before (probably due to the intake piping leading into the resonator being a few inches shorter). I feel the VTEC surge, but the sound is muted inksadface:

hopefully the replacement part will age better and eventually collapse again!

Now everybody to take your Si to redline under WOT and see if you also have the same problem!:vtec:

 

[Falchon1]

Glad you go it figured out! :cheerleader:

 

[Taff7Si]

effective Hot-Air-Intake (drawing air from engine bay) FTL at:


:violin:

 

[41954]

Bad design ftl.

 

[Taff7Si]

Just got the replacement part put in, looks nice and greasy like the one in this pic:

Everything's workin perfect again! (WOT to redline, VTEC intake growl is back:vtec

Thanks to Lester and Kevin at Markham Honda for takin care of this! :canada:

 

[Taff7Si]

found a little blurb on the fender intake:

"Honda worked to intensify the cam switchover at 6000 rpm, and it now feels as if someone had flipped a switch and turned on some hidden power source, and there's nothing subtle about it. Adding to the change in character is a tuned air intake that tunnels out of the engine compartment, into the fender area, and back to the intake manifold. By routing the intake through the fender, the sound of the engine switching to high-revving cams is amplified because the fender acts as a resonator. With the driver's window down, the switchover sounds like a karaoke version of a Ferrari V-8 aria. The only negative aspect of the engine is its predilection to hang on to revs after you lift off the accelerator — a trivial annoyance."

2006 Honda Civic Si - Comparison Test / 2006 Honda Civic Si vs. Volkswagen GTI - Comparison Test / Hatchbacks / Comparison Test / Reviews / Car and Driver - Car And Driver

:dance:

 

[adeshsharma]

i have the same problem. i tried to replicate it by opening the hood and watching the rubber tubing that goes into the fender to see if it collapses when someone revs the car....lol unfortunately it seems the car doesnt rev past 4500 rpms when parked though, so i saw no change.

 

[jaxson]

Hmmm can that piece be removed easily? If so I may try to stiffen it with something.

 

[adeshsharma]

i was thinking the same thing...according to Taff7Si when it was removed, the vtec started to kick in again, without the regular vtec growl. So when i get home im just gonna take mine off, if the vtec starts kicking in again, at least ill know it is the rubber tubing.
do you guys know of any other parts of the intake system that might be collapsing?