Jump to content
SAU Community

Finally Nailed My Lack Of Mid And Top End Problem!

mabru

By mabru,
in Engines & Forced Induction

 Share

Recommended Posts

mabru Enthusiast

mabru

Posted
Posted

I've been digging at this problem for a while. I have an R32 with RB25DET with most of the usual mods on it. The car never felt as fast as my old 32 with the RB20DET. I noticed a few strange sensor settings when I first bought the thing which led me on a wild goose chase. Making matters more difficult is the fact that the consult port isn't wired up and the ECU has no LED.

I never bothered to look at the knock sensors because I installed an SAFC and it was reading knock just fine (or so I thought). I finally looked under the manifold and whoa! the knock sensors have no wires coming out of them. I had to custom make a harness for them and plug them into the ECU since the engine install was a hatchet job, I wish I knew what shop did so I could avoid them in the future.

Long story short, I plugged the knock sensors into the harness and it pulls like a mule. I can't believe I didn't look sooner. So if anyone out there has symptoms that sound like mine, do yourself a favor and check out the knock sensors.

Sorry for the long post but I'm extremely happy right now :)

-Matt

Memph Proficient

Memph

Posted
Posted
  OnDubz said:
hey, ive been trying to look for my knock sensors in my rb20 also, but i cant seem to find them. Can you explain roughly what they look like, a pic would be excellent.

thanx

I am no mechanic so my description may be a little off..

But im pretty sure on the RB20 they are on the side of the block under the intake manifold... as for looks you cant really see much from the out side.... but if i remember correctly they have a orange or red plug.. but theres a good chance i just made that up...

hehe.. have a hunt around there anyway. pretty sure you should find them :D

Sorry for lack of help but no one else has said anything so i thought i would give you a start :O

Cheers

OnDubz Explorer

OnDubz

Posted
Posted

hey, thanx memph :D , i had a look, but all i could find where these two things that went into the block that kinda looked like o2 sensors, probably about 3-4cm long and about 1-2cm in diameter, with a single wire coming out the top of them. Is that them?

paulr33 Grand Master

paulr33

Posted
Posted
  mabru said:
I've been digging at this problem for a while.  I have an R32 with RB25DET with most of the usual mods on it.  The car never felt as fast as my old 32 with the RB20DET.  I noticed a few strange sensor settings when I first bought the thing which led me on a wild goose chase. Making matters more difficult is the fact that the consult port isn't wired up and the ECU has no LED. 

I never bothered to look at the knock sensors because I installed an SAFC and it was reading knock just fine (or so I thought).  I finally looked under the manifold and whoa! the knock sensors have no wires coming out of them.  I had to custom make a harness for them and plug them into the ECU since the engine install was a hatchet job, I wish I knew what shop did so I could avoid them in the future. 

Long story short, I plugged the knock sensors into the harness and it pulls like  a mule.  I can't believe I didn't look sooner.  So if anyone out there has symptoms that sound like mine, do yourself a favor and check out the knock sensors. 

Sorry for the long post but I'm extremely happy right now  :)

-Matt

glad u got it sorted. odd problem. what the safc showing for knock values?

mabru Enthusiast

mabru

Posted
  • Author
Posted
  paulr33 said:
glad u got it sorted. odd problem. what the safc showing for knock values?

Memp is correct on their location, as for color mine have a clear-ish plastic covered cap with the wire then the top of the sensors themselves are green with a rubber o-ring. They are little cylindicral jobs, #1 is between cyls 1 and 2, and #2 is between cyls 5 and 6. You can't really see them unless you take the intake manifold off. I was able to unsnap the connectors with everything on the car from the top, I did get scraped up a bit and I don't have HICAS so that makes it a lot easier.

I bought the car the way it is, it seems that whoever performed the motor swap didn't hook them up and tried to compensate by adjusting pretty much every other sensor. As soon as I got the car I started putting everything back to FSM spec and my performance went out the door. It's stronger than ever now though :)

The SAFC threw me because it was actually reading knock levels similar to what I was used to on an RB20DET so I didn't think anything of it. The car ran really well off the line (VVT I'm sure) and at low boost but after that the ECU would yank the timing out.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Latest Posts

    • GTSBoy
      New Honda prelude at Goodwood

      By GTSBoy · Posted

      Well, in the same way that you can't tell any SUV from any manufacturer in any size category from any other one, "sports" coupes now all look identical. Stand back and squint your eyes and the Supra and the 400Z and the GR/BRZ things all look the same. I was just thinking last night, when sitting behind a Subaru CrossTrek, that I have no idea what it is, how it differs from an XV, or a Forester, or an Outback, or anything else Subaru offer, and I couldn't tell if it was supposed to be small, medium or large. I contrasted that to the good old days, where a HQ Kingswood had familial similarities to an LJ Torana, but there is no way that you could confuse them, and how a bit later, the HX Kinger and the concurrent Torana and the Gemini all had familial similarities, but you still could not confuse them. Ditto the ugly Fords and Chryslers of the era. But now, a RAV4 looks like a Kluger, looks like a Yaris/Cross/whatever they're calling those stupid f**king things, looks like every other Toyota that's not a Camry/Corolla sedan.
    • Rezz
      New Honda prelude at Goodwood

      By Rezz · Posted

      The Prelude doesn't look that bad without all that lens distortion in those pics. Makes it look disproportionate when it isn't. Actually I kind of liked it at the Osaka Auto Messe earlier this year. 
    • Dose Pipe Sutututu
      Ethanol Content Sensor - Always at 11%?

      By Dose Pipe Sutututu · Posted

      Pour in the highest octane, non-ethanol fuel you can get and see if the readout changes. If it's dead bang on 11% then I would question the sensor. Another quick test, just take it out and run normal (in an american accent) gas-o-line through it and see if the sampled ethanol or lack of changes.   United E85 here in the land of drop bears does vary a bit, I've had as high as E87 (could be water in their tanks too, who knows)
    • GTSBoy
      FS5R30A rb25det neo 5 speed trans

      By GTSBoy · Posted

      Yep. And if you ever do, you'll just have to deal with it then.
    • joshuaho96
      Ethanol Content Sensor - Always at 11%?

      By joshuaho96 · Posted

      E10 is pretty tightly regulated in percentage. Too much and engines can't adapt. Every incentive is against them to have too little ethanol though. The more ethanol the higher the octane.
×
×
  • Create New...