Dead/Sluggish area around 2300rpm. Spec S

[-BigDave-]

Hi guys. I've been recently experiencing a dead patch in acceleration when then engine is cold on my Spec S. It occurs around 2300rpm. It accelerates fine up to this point but then seems to hesitate and struggle for a second or 2 and then accelerates away fine again after this patch. It hasn't happened when the engine is warm.
I recently fitted a big HKS cone filter. Could this be causing the problem? Only other things I can think of would be spark plugs or my air flow meter. What do ye reckon it could be? Should I start by cleaning the AFM?
Thanks!:thumbs:

 

[S15_SAM]

Does sound like AFM, especially if you've fitted a cone filter recently. Would clean it and put the air box back on! Drill some holes in the underside of it if your want induction roar. Cone filters are **** on NA's

 

[Auss15]

Has the NA Spec S got VVT ?

 

[-BigDave-]

Has the NA Spec S got VVT ?

Yup they all have VVT.

 

[spoonman]

Nothing to do with your VVT,
Dont drill any holes.

Rotate your AFM around about 20 deg at a time until it stops doing this. DE engines and the stupid stock AFM when a aftermarket filter is put on have this issue every now and again, the AFM will be getting a certain flow on one part of the sensor and a different flow on the other side, not a straight through flow and this will vary depending on the aftermarket filter you have put on. Another option if rotating the AFM does not work is to put an extended pipe between the filter and the AFM. Think of it in terms of the air going through as a vortex or spiral not a straight flow, when you look inside the stock AFM you will understand why this happens.

While you are at it spray the little sensor electrodes with something like CRC AFM cleaner, or any contact cleaner for electrical things. but DONT touch them with ANYTHING, dont adjust there distance from one another.

 

[J0R04N]

As above ^ if you want to run an aftermarket filter you must use either the HKS or Apexi filters as they have the Venturi design which ensures the flow is even and also prevents "tumbling air"

 

[spoonman]

As above ^ if you want to run an aftermarket filter you must use either the HKS or Apexi filters as they have the Venturi design which ensures the flow is even and also prevents "tumbling air"

This has happened on a Apexi, power intake even with the 1" neck extender......with sensor at the bottom it suddenly worked

 

[spoonman]

Double up, delete post

 

[-BigDave-]

Cheers for the help guys. The Cone filter I put on is a HKS one. I fitted decat pipe a few days ago and it hasn't happened since which I find odd. But if it does start to happen again I'll try the above suggestions. Thanks