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Finally Nailed My Lack Of Mid And Top End Problem!

mabru

By mabru,
in Engines & Forced Induction

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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
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
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
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.

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