Hey,

Here's the deal. Ever since I've completed my JDM B18c swap almost a year ago into my JDM Ferio EG9 running stock P72 ECU. I've been having very sluggish performance around 3000 to 4500rpm. I initially thought it was the fact that it was due to the IAB not working but I have fixed that problem now and there has been a little bit of improvement.

However, there is still this huge flatspot around those rpms. You don't really notice it in 1st gear gear but you definately notice it in 2nd and 3rd. It is most noticeable at part throttle (half to 3/4 throttle). The car doesn't violently jerk and stutter as such but you can kind of "feel" it like the power is coming on/off/on/off etc until it gets to VTEC engagement then it goes sweet as.

So I have come to the conclusion that it may be the knock sensor "kicking in" because it senses a little bit of knock and therefore causing that flatspot. Would I be correct? What does the knock sensor feel like?

From my symtoms I can perhaps assume that:

1. I don't feel the flatspot in 1st gear because there isn't much load on the motor and therefore no pinging.

2. Happens only in gears with higher loads and part throttle as knock sensor does not pick up pinging in WOT?

3. Also heard that the knock sensor works up to a certain RPM as there is high engine noise at high RPM. Therefore anything in VTEC is sweet as.

Car is not throwing any codes at all. In terms of top end performance, it's pretty good. I have run 14.5 @ 96mph (want to get 13's soon!). Full interior sedan minus spare tire and tools. Mod's are I/H/E pretty much.

Please help!

 

knock sensor "kickin in?"

never heard of that before..

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by instrument &raquo;</TD></TR><TR><TD CLASS="quote">knock sensor "kickin in?"

never heard of that before..</TD></TR></TABLE>

Any Cels? If it is knocking, you have bigger problems....

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Tuesday Club &raquo;</TD></TR><TR><TD CLASS="quote">

Any Cels? If it is knocking, you have bigger problems.... </TD></TR></TABLE>

No cels. Can't hear any knocking. Does the knock sensor pick up slight knocking or only heavy knocking?

By "kicking in" i mean when the knock sensor actually starts pulling back timing, can you feel it like a lose of performance, stuttering, etc.

 

basicallyit retards the timing, and throws a cel, and if you hear the car knocking you have bad problems and might be time for a rebuild

 

I always thuoght the knock sensor is sense if there is any knock in the engine and make changes to the engine so there wouldnt be any knocking?

 

The knock sensor senses detonation below 4000 rpms... it doesn't work above that, since the mechanical engine noise makes it hard to find knock.

 

So when the knock sensor retard the timing, can you noticably feel it on the but dyno?

 

Probably not. You would need software like ECU Control or preferably, Crome PRO so you can datalog and see when its retarding the timing, due to the knock sensor.