California Civic HX - how about installing a Federal ECU?

[SpeedyCorky]

Well word on the streets says the the California model HX does not have lean burn. This limitation is due to the different ECU for the CA version. I have a 2000 HX, California version. BUT! According to my UltraGauge, i can get into what looks and feels like lean burn, in that i feel a power loss when it goes into lean burn, and a power gain when it exits. This entering and exiting lean burn is confirmed by the UltraGauge when the 2nd O2 sensor reads "0" (when it enters lean burn), then raises back up to .7 or .8~ once it has exited lean burn

Now, i can only stay in 'lean burn' for about a minute, usually a lot less. getting it into lean burn, you gotta throttle up to a good 90% load for a few seconds, then back off throttle down to 30%~, and it *usually* goes into what looks like lean burn (or what looks like lean burn as described above).
well, is it actually lean burn?! i have my doubts.....mostly because no matter how sissy I am with the throttle, i cant get it to stay in lean burn (obviously increasing throttle takes it outta lean burn right away); but also i'm not sure if i'm actually in lean burn, simply because of the fact that i've heard that the CA version doesnt even have lean burn! so wtf!? yes, I do notice a *instantaneous* MPG increase when it is in "lean burn".

so I guess the first thing to ask is: am I in lean burn?
if not, then whats going on? maybe the CA ECU only allows lean burn for a very short time?


next thing to ask (back to the post topic):
would swapping in a 49 state (federal) version HX ECU, enable me to properly get into lean burn (and stay there)? so basically, is the ECU the only difference between a CA and a Federal HX?

yes, my car has a 5 wire 02 sensor.

54mpg on my last tank.... but those numbers are for sissycakes - i want 60!!!!

[turbovr41991]

I beleive the ultragauge can look at the rear 02 sensor. When it reads 0 and you are still giving it gas you know you are in lean burn. Still really solid numbers!

Many people say the EGR plays a large part in lean burn. Try cleaning that out as well as the EGR passages under the fuel rail.

Not really sure on the cali to fed differences. I think I have read they still can get into lean burn but are not as agressive air to fuel ratios as fed?

[SpeedyCorky]

i've cleaned out the EGR, it was pretty clean when i was in there. I did not remove the whole fuel rail tho - however I doubt that is the problem, considering how clean it was around the EGR itself


UPDATE: on my way to work today I was *somehow* able to keep it in lean burn for a good couple minutes. the motor was semi-cold (not fully warm, about 4 minutes from startup time) when i was able to achieve this. However, as the motor warmed up more (about 20 minutes from start up), i was unable to get it into lean burn for more than a few seconds..... WTF is going on!? is the CA ECU screwing me?

granted, for the couple minutes that I was able to keep it in lean burn - i got VERY good *instantious* mileage, like a good 8mpg more than i would normally get during that section of my commute.

[turbovr41991]

Originally Posted by SpeedyCorky

i've cleaned out the EGR, it was pretty clean when i was in there. I did not remove the whole fuel rail tho - however I doubt that is the problem, considering how clean it was around the EGR itself

My EGR was pretty clean too, but inside that chamber under the fuel rail was COMPLETELY clogged. Man it was clogged up. Here is my cleaning link:
http://ecomodder.com/forum/showthrea...-hx-22824.html

Originally Posted by SpeedyCorky

UPDATE: on my way to work today I was *somehow* able to keep it in lean burn for a good couple minutes. the motor was semi-cold (not fully warm, about 4 minutes from startup time) when i was able to achieve this. However, as the motor warmed up more (about 20 minutes from start up), i was unable to get it into lean burn for more than a few seconds..... WTF is going on!? is the CA ECU screwing me?

My car pops right into low RPM lean burn on a semi “cold” engine. Depending on where I am and what I am doing it is normally about 5 minutes into the drive or so. After warm, try going to 2400-2550 rpms with TPS at 19 and LOD 65 or less. I get right back in instantly, but need to maintain 2350+ rpms or so to stay in lean burn.
There is a lot of learning to driving with lean burn. Keep trying new things and you will get the hang of it.

[Weather Spotter]

it may be a simple ECU programing for CAL, or you may have a different environmental system.

you are only shooting for 60 MPG? I get 65-75 MPG out of my matrix

[darcane]

Originally Posted by SpeedyCorky

i've cleaned out the EGR, it was pretty clean when i was in there. I did not remove the whole fuel rail tho - however I doubt that is the problem, considering how clean it was around the EGR itself


UPDATE: on my way to work today I was *somehow* able to keep it in lean burn for a good couple minutes. the motor was semi-cold (not fully warm, about 4 minutes from startup time) when i was able to achieve this. However, as the motor warmed up more (about 20 minutes from start up), i was unable to get it into lean burn for more than a few seconds..... WTF is going on!? is the CA ECU screwing me?

granted, for the couple minutes that I was able to keep it in lean burn - i got VERY good *instantious* mileage, like a good 8mpg more than i would normally get during that section of my commute.

My Civic (7th gen) is also a Cali Civic and has lean burn. It took me a little while to get the hang of it, but now I can keep it in LB for nearly all of the 18 mile highway portion of my morning commute (it usually blips out for a couple seconds 2-3 times).

I watch TPS% on my ultragauge and changes in TPS must be VERY slow (less than 1% change per second) or it kicks me out of LB. Doing this, I can accelerate and get TPS up to as much as 29%, or slowly slow down.

[SpeedyCorky]

all good info - thanx!

on my way home from work today, i was able to get it to stay in lean burn for a good several minutes; but again, once the car got totally warm, i was unable to get it back into lean burn for more than a few seconds. good to know about the ~2400 rpm minimum for lean burn on a warm engine.... also, i will go take apart the fuel rail and clean it.

I ordered up a 49state (federal) ECU today. cost me a bit over 100bucks. not horrible if it does NOTHING, however i expect/suspect it will do a lot, lets hope so. i'll report back with the findings.

on this trip home today that i managed to keep it in lean burn for most of the trip, i usually get around 55mpg on that commute home - however with keeping it in lean burn as described, i averaged 61mpg on the commute home! thats a 6mpg difference, and i wasnt even in lean burn the whole time... i'll betcha i could even get a bit more out of it....maan 60mpg overall per tank seems VERY obtainable now.... maybe a more reasonable long term goal would be 65 or 70mpg !


oh yeah, and weatherspotter - no fair, u are running a crazy looking boat tail and all that jazz! cheater! lolz

[Weather Spotter]

Only driving tweaks can get my non lean burn 1.8L car to 45- 50 mpg. Your car shoul be able to get 60mpg all day and 90 mpg if you mod it.

[SpeedyCorky]

weather spotter: you are more than welcome to come drive my car; if you can average better than 60mpg, i'll buy you lunch...


OK folks, so I got a Federal HX ECU and installed it. it works, car runs great, no issues. YES i am able to get into lean burn MUCH easier, and I am also able to stay in lean burn MUCH easier. so i'm going to stamp "success" on that venture....


BUT.... seems that the federal ECU has *what i assume to be* some kind of minimal RPM that the engine must be at for it to be able to go into lean burn; seems to be around 2400rpm minimal. which in 5th gear means about 65mph. which means I must drive 65mph or faster to get into, and stay in lean burn. the CA ecu I was able to get into lean burn as low as 60mph, and was able to stay there to perhaps as slow as 50mph. So granted, now to stay in lean burn i'm having to drive faster, which means more wind resistance, which means my mileage didnt really improve!!!! GRRRRRRrrrrr! in fact, if anything, it decreased!

with the CA ECU i was getting about 54mpg on my commute to work, staying in lean burn maybe 30% of the time on the freeway. Now with the Federal ECU, i'm able to stay in lean burn for closer to 90% of the time that i'm on the freeway - but because of the minimum ~65mph limit for lean burn - my average mileage for my commute went down to about 51mpg!!! well good news is that i'm getting to work faster and spending less time in the car, while not taking that much of a MPG hit - but the question begs to be asked:

Is there any way i can trick the ECU to allow the car to go into lean burn at RPMs lower than 2400 ?!?! if I could get that limit down to say, 1800rpm, then I could putt putt down the freeway at a cool 55mph, and stay in lean burn, and likely get easily upwards of 60mpg.....

HELLLLLLP!

[1carnut]

Brucepick, turbo4vr and myself have kind of compared notes on HX Lean Burn in our 97 HX's. Brucepick figured out that adding a bit of Marvel Mystery Oil to the gas tank periodically helps the lower RPM (~1800) lean burn work better. I have confirmed the same. At the same time, I used to have a VX that went in to Lean Burn much more often, much more consistently and without all of the finesse needed for the HX. I'm trying to find someone that knows the difference between the ECU's or better yet knows how to modify the HX ECU to behave more like the VX. For the VX, all it really seemed to require was a warm engine and light throttle. So far no luck on finding anyone that can tell me how to tweak the HX.