xpenguin51

Parts question (goal is no CEL and maybe more power):
I have a 1998 Civic HX 5MT (D16Y5 VTEC-E).
It has the ECU that requires EGR, P2N-A31.
I understand the California ECU P2N-L31 does not have the EGR system required, but are there any other differences? i.e. that ECU might not like my 5 wire wide band O2 sensor or my 3 wire IACV? I also heard there is an upgraded ECU only available at the dealership, P2N-205, is this true and what are the details?
Thanks
Here are my current mods relevant to this question: (what would you guys estimate the HP is now? Was 115 stock... Maybe 140?) a non-Honda race car guy told me to advance the cam for more power or mileage, but do you guys think I should get an adjustable gear?
AEM short ram intake
B18 Throttlebody, knife edged throttle plate
Skunk2 Pro Series Intake Manifold (No more EGR so now I have a CEL)
IM Thermal gasket
4-2-1 Header
PaceSetter High Flow Catalytic Converter
Extended the O2 wires (Primary is a wide band 5 wire)
Custom exhaust
Straight through muffler
-- And then other stuff of interest:
7 lb chromolly flywheel
stage 2 clutch
short throw shifter
2006 Civic SI seats front and rear
Carbon Fiber hood
VTEC LED wired into blank light in dash looks like old school integrated arrow shift light
HD radio wired together with OEM radio to maintain keyless entry
new cam seal, crank seal, timing belt, rear main seal, cap and rotor, and axles
low resistance plug wires
Mishimoto full aluminum radiator
Samco silicon radiator hoses
failsafe thermostat
(I did all work myself in the yard except the exhaust, clutch, and timing belt, lol)

grumblemarc

iTrader: (4)

I read this 3 times and I still don't know what the question actually is. If you want to know how much horsepower you think you have spend the money and get it dyno'd. All in all it's still a Civic so it's still slow.

xpenguin51

The question is:
Can I change my ECU to the California version (P2N-L31), that has no lean burn mode?
What is that ECU expecting different from what is on my car?
(differences could be EGR, no wideband O2, etc.)

My car has the EGR on the intake manifold, but I replaced it with a Skunk2 that has no EGR port.
I would like to eliminate the CEL.
I would like to gain any HP I can without losing MPGs.

xpenguin51

So, no one knows the difference of what the ECU expects from California vs. Federal?
It is looking like it might only be a 4 wire O2 sensor instead of the 5 wire and no EGR... But before I buy a P2N L31 or some chipped ECU, I'd like to know.
My mileage went down from 36 mpg to 29 mpg after putting on the intake manifold and b18 throttle body, but I was "testing" the power quite a bit on the first tank.

xpenguin51

Ok, I figured it out.
I bought a P2N L22 from ebay, it was for the 97 HX 5MT in California. I plugged it up at lunch, car runs great, if not a little more peppy, and apparently the only difference was indeed the EGR. No 5 to 4 wire O2 or IACV issues.
I may still put my original throttle body on though to increase velocity and have it idle better.
Sweet, no CEL!
Hope the trip home is event-less.

xpenguin51

Ok, just for posterity's sake... The California ECU did also expect an EGR, but I have nearly the same mileage and it seems a little peppier, I guess that is the less aggressive lean burn.