KA24DE Emissions Removal FAQ

[BustedS13]

THIS IS A WORK IN PROGRESS, I WILL BE FILLING IN ALL GAPS. PLEASE DO NOT DELETE, THANK YOU!

I'm returning my s13 to the street, and in the process, am removing all emissions nonsense. Two reasons:
1.) Troubleshooting the KA, in my experience, is consistently a NIGHTMARE because of cracked/leaking vacuum lines.
2.) Emissions for OBD1 in my area consists of a visual for the carbon cannister, cat, and EGR piping, if they even bother to check. when my car goes in for inspection, it will have the shell of a cat bolted to a test pipe, and none of the other crap. we'll see what happens

While searching here I found a lot of information but had to do some digging. I'm putting all information here in this thread so that I can have a set of reference material, and so that others can benefit later. This will also, in time, contain my own experience. I will attempt to give credit for every quote i pull. Let's begin:

EGR

http://forums.nicoclub.com/zerothread?id=109345http://www.project-mayhem04.com/EGR%20Removal.html
pretty nice writeup concerning most of the intake mani, not just the EGR piping. recommends not disturbing the PCV. i beg to differ

some recommend replacing the EGR temp sensor with a resistor:

Originally Posted by SilviaSativa

The resistor is replacing the EGR Temp sensor. Cut the wires off the EGR temp sensor, solder one end of the resistor to one wire, repeat on the other end. I believe it is a 10k-ohm, 1/4 resistor

AIV (PAIR)

description

Pulsed Air Induction Reed Valve - for all intents and purposes, it's the smog pump. Its job is to introduce fresh air into the exhaust upstream of the cat/con during deceleration and extended periods of idle to help keep the cat "lit off" (at operational temperatures). The PAIRV disappeared from the engine in '94, with Nissan citing engine improvements being responsible for no longer needing it.

removal


PCV

description:

The PCV system is intended to
relieve the crankcase of any positive pressure by allowing it to vent through the free flow of air, either into or
out of the crankcase. Prior to advent of emissions, the crankcase was just vented through a breather on the
valve covers or intake manifold to the environment. Emissions requirements necessitated a “cleaner” way to
vent the crankcase to prevent the hot oil laden vapors from damaging air quality. That led to the inclusion of
today’s modern PCV systems. Current PCV systems are still pretty simple, consisting of an air inlet, a valve,
and an outlet. The air inlet (the vent tube) supplies filtered and metered airflow into the crankcase. The PCV
valve, which when opened by either internal intake manifold vacuum or positive crankcase pressure, vents
into the intake manifold, allowing the now oil contaminated but otherwise filtered and metered crankcase ventilation
airflow to be consumed by normal combustion processes.

removal:
http://www.ka-t.org/forums/viewtopic...er=asc&start=0
method removes more vac lines, plugging the intake mani holes.



carbon cannister

post removal issues

EGR

Originally Posted by BigVinnie

Yeah you got that right and the fact that exhaust gas no longer takes the space of air in the cylinder chamber during compression. It also completly FUCK's up the O2 signal.
That also means that it retards ignition timing so the engine technically will run like shit.
A retuned ecu will fix that problem by changing the A/R ratio. Or even a piggy back will work by fooling the MAF signal to the ecu that it is getting less air than it really has (somewhat correcting the problem by shrinking the pulse width of the injection in the cycle).
KA's run rich with there stock tune to begin with. The stock tune increases fuel richness by 7% more fuel than air at low rpms. Poor stock tune along with removal of smog equipment is one rich KA.

reasons to remove equipment

AIV (PAIR)

Originally Posted by nastjuid

The AIV (PAIR)... Was actually removed in the S14s because all they did was cause problems. The valve gets stuck open, and the sensor element in the MAF gets coated and you start having problems that don't diagnose a like MAF misread. Or something along those lines.

if anybody has anything to add, please do so!