In a nutshell (hopefully)
I had my S/C'er (HBP) installed about three weeks ago (CLS-6). The IRMC was not disconnected and I noticed detonation occurring while heavy on the throttle. Disconnected the IRMC and detonation disappeared. Last Sunday, on my way home from my parents house in Central Florida, I made a stop at one of the Turnpike rest areas and notice a ticking sound coming from under the car (no CEL light present). Open the hood and also heard said 'ticking' sound (more pronounced) coming from the rear valve cover. (The rear head was replaced back in Oct 2004 for bent valves) Monday, I take the car to the dealer for a diagnostic to determine the cause of the 'ticking' noise. End result, the rear valves were adjusted and the ticking sound has ceased.

Interesting note: As part of the diagnostic process, the mechanic checked the ECU for stored codes (even though the CEL was not illuminated). He said he found a 'Temporary DTC code' (forgot to get the code) and explained that this temporary code would not cause the CEL to light-up, but, would never the less, still be stored in the ECU. He explained that he was able to trace it back and stated that it was caused by the disconnection of the IRMC switch on the actuator mechanism. Moreover, he stated that as a result, the VTEC selinoid (sic) would have been disabled, thus not allowing VTEC to function at the 4800rpm point.

Now, before I had the S/C installed, VTEC was that terrific sound we all love to hear when accelerating rapidly. However, when one installs the S/C, the whine of the blower now becomes the intoxicating sound to listen for.

When he reassembled the car, he told me he reconnected the IRMC. However, he disconnected the Plenum linkage to the actuator to prevent it from opening.
He explained that this would fool the ECU in thinking that the IRMC was connected, preventing a 'temp. code' from being generated, while still leaving the plenum disabled. Thus, preventing detonation and enabling VTEC to function normally at 4800 rpm and above.

Now, I guess I will hand the discussion over to some of the more knowledgable folks to explain if this is accurate or not. In addition, how would one know that VTEC is functioning when the whine of the blower supercedes that once familiar VTEC sound???

Sorry for the verbose post, just trying to paint an accurate as possible picture.
Peace.

 

interesting

 

You might want to call Comptech to see what they have to say about this new situation.

 

VTEC still engages even without the IMRC connected.

Take a look at 4800 rpms (VTEC engagement). This is with the IMRC disconnected.

 

When I picked up the car today from the dealer, it felt alot better in throttle response, even though the humidity was around where it should be for this time of the year. My fuel pressure has stablized down from 36 psi to around 30 to 32 psi during idle and stop and go traffic. I have not had a chance to open it up a little yet, but, from the way it feels now, it's gong to be hard to keep the wheels from breaking loose

 

Your fuel pressure should be between 35-38 at idle.

 

I talked to Shad at Comptech last week regarding the lowing of the FP and I mentioned that I thought perhaps it was due to the hotter/humid conditions down here in the south vs some of you guys up north with dryer cooler air. He said to keep an eye on it.

 

My dealership has spoken with Shad and he says they "don't have numbers for where the fuel pressure should be with the HBP."

According to other S/C owners on the forum though, fuel pressure should be between 35-40psi at idle.

 

mine is around 30 psi at warm idle. In the morning when its cold it like 35psi

 

I'm surprised that you have a pinging problem in Florida. What type of gas are you running? I thought running 93 octane and above would run HBP with no problem and no need to disconnect the IMRC. I always figured that us West Coast guys with 91 and 92 octane were the one's that are limited.

 

Nope, another S/C'ed member: cartan, who rarely posts lives about 20 minutes from me. 6-speed, HBP, and he had pinging with the IMRC.

I knew better so the IMRC has NEVER been connected since the S/C was installed.

 

I'm in central FL(hot/humid) but I haven't experienced what you are describing. That is very unusual. I hope you can get to the bottom of it.

 

That's very close to how mine starts out and ends up as well.

George, Jason and Dean told me about all the mod's on your car. All I can say is WOW! I discussed the FP question with Jason today. (My car was their first CLS-6 S/C install) He recommended to check the FP with the vacuum line disconnected to see what the FP read is. I will do this on the weekend at my brothers business, do not really have alot of room at my condo complex.

I use Shell V-Power 93, so, since I'm not getting any lean ECU codes or detonation at WOT for the moment, maybe my car is just different when it comes to the 'Fuel Pressure' aspect. I had a hard time keeping the wheels from braking loose today. Otherwise all is well so far.

Does anyone have any comment on the validity of the IRMC effect on the functioning of VTEC??

mrsteve posted his dyno with VTEC working with the IRMC disconnected

Thanks.

 

I can still "feel" VTEC, though less pronounced w/ the blower. My IMRC is disconnected (unplugged).

 

It's pretty obvious that I can also "feel" VTEC based upon the dyno. A jump on 20whp and 20wtq in under 200rpm is definitely noticable!!!