California Civic HX - how about installing a Federal ECU?

[Weather Spotter]

If I ever get out your way I might just drop by and see if I can get better then 60 mpg. If not its still fun to try

[SpeedyCorky]

^^^^^^ and no installing any cheater boat tails to do it! hahaha

[SpeedyCorky]

Originally Posted by 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.

read this then left on my commute home; totally thinking you were pulling my leg big time about this "Marvel Mystery Oil" hahaha i was like "what kinda snake oil is this guy trying to get me to put into my gas?!" hahaha then i googled it, and its an actual product! hahaha i'll give it a shot, but I have some other things i need to try first.

on my commute home today I was able to get it into lean burn below 65mph, at around 60mph, and even slowed as low as 55mph w/o getting out of lean burn. no idea how i did it, but still i'd say thats a positive sign. however it seems much harder to get it into lean burn at such low speeds (read: RPMs). but yeah wow, the Federal ECU you really can get on the throttle a lot before it will jump you out of lean burn, i was at 22% TPS and 82% engine load going up a hill, and was still able to stay in lean burn. only 2 commute days on the Federal ECU, and many weeks on the california version. I know it took a long time to learn the CA ECU, so I suspect I still have a lot to learn about the Federal ECU nuances.

so do the 1995 to 1998 HX's have a lower RPM limit for lean burn? or are you just saying that the Marvel Oil helps it?

If the HX ECU cant be tricked to get into lean burn at a lower RPM, then it looks like further aero mods are to become a MUCH higher priority

[1carnut]

I was a skeptic on the MMO at first as well. I'm not sure of the science behind it but it does seem to allow the lower rpm (~1800) or just about 50 mph for me to engage. That being said, I still have a lot of situations where it will go back out of Lean Burn under these same conditions and not re-engage. I'm not sure why. That is why I'm trying to find someone with some expertise that might be able to tune this ECU to be closer to the VX. I didn't have to do anything special on the VX. No MMO, no watching rpm's or speed. It just engaged Lean Burn on light throttle and took it out if you had to get back on the throttle to climb a hill or something. I've read in a couple places that it might be possible to go back to an OBDI ECU and then tune that but I don't want to lose the monitoring capabilities that I have with OBDII if I don't have to. A lot of my commute is back roads with hills and curves so I can't really leverage lean burn very much on the HX as it is now.

[turbovr41991]

I am also researching other ECU / Tuning options. It would be nice to know what is entailed in running a Stock VX ECU. It would be sweet if it as simple as getting a jumper harness and a VX fed spec ECU. Then have a much easier time with lean burn.

And I also find MMO helpful.

[mugen]

Good new for all HX owners
I will have a tuned ECU for increased Lean Burn Capabilities
Lean burn available in any gear
lean burn under many more conditions than OEM.
should be a really nice addition to hyper mile techniques.
should be available for Christmas 2012 (or sooner)
call the shop for details
614-504-5357

[1carnut]

Originally Posted by mugen

Good new for all HX owners
I will have a tuned ECU for increased Lean Burn Capabilities
Lean burn available in any gear
lean burn under many more conditions than OEM.
should be a really nice addition to hyper mile techniques.
should be available for Christmas 2012 (or sooner)
call the shop for details
614-504-5357

I will most likely be very interested in one of these. Please also post the details here when you know them.

[turbovr41991]

Originally Posted by mugen

Good new for all HX owners
I will have a tuned ECU for increased Lean Burn Capabilities
Lean burn available in any gear
lean burn under many more conditions than OEM.
should be a really nice addition to hyper mile techniques.
should be available for Christmas 2012 (or sooner)
call the shop for details
614-504-5357

Also very interested in this. I am sure many other HX owners will be chiming in with interest in this too.

[brucepick]

Also interested to know more.

Mugen, as you're working on this, can you say. What air:fuel ratio the stock HX has? I've always wondered. And of course tell us what AFR ratio(s) you build into your box.

Marvel Mystery Oil has been mentioned here and yes, I use it in every tank. It gets me lean burn down to about 1800-1900 rpm. Could take you a few tanks with MMO to get those results but its worth it.

I tested various ratios for MMO and settled on 2 oz. per 10 gallons fuel. I got a ADJUSTABLE one ounce measuring cup from a cooking store to measure it out, and a funnel with tube. Cup is available from Amazon for just a few bucks, also.

[1carnut]

I also would like to know the difference(s) between the VX ECU and the HX ECU. I realize that one is OBDI and the other OBDII but I didn't have to use MMO and had lean burn whenever the engine was warm and I was using a light throttle on the VX. My guess is that this is probably the biggest reason that the VX got such higher mileage than the HX.