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Si How Do You Adjust A/f?


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#1
PoSCiViC

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I heard you can only adjust with an fuel pressure regulator is this true? I just need to lean it out without getting all technical.. Most cars have a screw... Shouldnt this one!? lol

#2
Omega Mugen

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Reprogramming the map in the ECU is the correct way.

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#3
myheadhertz

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QUOTE (PoSCiViC @ Oct 4 2007, 12:27 PM) <{POST_SNAPBACK}>
I heard you can only adjust with an fuel pressure regulator is this true? I just need to lean it out without getting all technical.. Most cars have a screw... Shouldnt this one!? lol


Maybe you've got a bad injector, a vacuum leak, or bad O2 sensor?
I'd check those first.

But, your car does have an undocumented A/F adjustment screw!
Back out the left-hand driver's sun visor mounting screw 1/8th turn and see if that leans it out.



#4
oldschoolhondacivic

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no no no...just crimp the fuel line like a garden hose,like you did when you were a kid....
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#5
PoSCiViC

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QUOTE (oldschoolhondacivic @ Oct 4 2007, 12:32 PM) <{POST_SNAPBACK}>
no no no...just crimp the fuel line like a garden hose,like you did when you were a kid....



wow.

#6
DEIVIONCRX

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QUOTE (myheadhertz @ Oct 4 2007, 01:20 PM) <{POST_SNAPBACK}>
But, your car does have an undocumented A/F adjustment screw!

Your actualy almost right. But its in the Black Box rivited to the metal frame. I didnt touch it when i took mine apart. But its only for idle i think. IMA Sensor i think.
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#7
syko_tek1

Yeah it's in the black box a round item with two rivets holding it in (and the brass cover on) it does only adjust mixture level at idle. It has a flat head screw under the brass colored cover, you need a A/F meter to properly adjust it. I had to turn mine down when I installed d16y8 injectors to get a good idle.

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#8
cbstdscott

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I have never heard so much crap in all of my life! Shame on all of you for doing that to a newb!

The factory did not give you an adjustment because they did not want anyone messing with the mixture. Adding an adjustable fuel presure regulator gets around that problem.

On a 1988 and later Honda, hacking the ECU is an alternative. But there is no known hack for the 85-87 Si ECU.

But your problem is that you are running rich, probably because your O2 sensor is screwed up. Bad values from that Fuggered sensor makes the engine runs rich. A new O2 sensor costs less than $30.

Scott
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#9
myheadhertz

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QUOTE (cbstdscott @ Oct 4 2007, 10:03 PM) <{POST_SNAPBACK}>
I have never heard so much crap in all of my life! Shame on all of you for doing that to a newb!
Scott



You are right Scott. Sorry, I started it.
Didn't notice that PoSCiViC was a brand new RPR member.
I thought my comment was so implausible that it would be blown off immediately. My stupid advice started the ball rolling.
But, LOL! "...the black box a round item with two rivets holding it in..." gotta admit that was real good though. Had me going!

I'm sorry PoSCiViC. No malice intended.

#10
syko_tek1

I'm not screwing with the noob the round thing in the black box does adjust idle mixture.
It has 3 wires going to it and it does richen/lean the fuel mixture at idle (it is not documented anywhere in the service manual).
This is what it looks like when out of the black box.

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#11
cbstdscott

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QUOTE (syko_tek1 @ Oct 6 2007, 09:49 AM) <{POST_SNAPBACK}>


That is a Throttle Position Sensor, not a mixture adjustment.
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#12
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He's right Scott, that's the IMA (idle mixture adjuster) and it is in fact located inside the black (vacuum line infested) box.

I've never adjusted one before though, never needed to.

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#13
cbstdscott

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QUOTE (jsgprod @ Oct 11 2007, 09:37 AM) <{POST_SNAPBACK}>
He's right Scott, that's the IMA (idle mixture adjuster) and it is in fact located inside the black (vacuum line infested) box.

I've never adjusted one before though, never needed to.



OK.
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#14
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IF the air fuel is off, its because something is wrong.
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#15
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I am in agreement with scott. I believe it would be the O2 sensor. But remember, once you replace the sensor, you need to unplug the ECU and allow it to clear out the code it has in it currently.
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