1997 Civic CX to HX engine/VX trans swap! 63 MPG @ 62 MPH

[brucepick]

Originally Posted by Jakins

Is LOD scan gauge talk for something?

And is there any write ups on what to wire an led or gauge up to see when you are in lean burn?

I really hate to thread jack, I'm sorry haha. I'm just a really curious person. The car looks great with the HX wheels by the way. I'm surprised you opted to keep the a/c

Not a thread jack - your question is ON topic, IMHO.

LOD is the ScanGauge display for Load. Not sure if that's percent or what. At
max throttle I couldn't get past the 90's. TPS is Throttle Position Sensor on a ScanGauge.

Somewhere is a write up for an LED indicator for a VX. I never found one for HX, don't know if the VX LED works on the HX.

[turbovr41991]

Originally Posted by brucepick

I checked speed vs rpm's in my HX this morning. Before using Marvel Mystery Oil in my fuel, it needed approx 2500 rpm or better to get lean burn. Nowadays I can run lean well below 2000. So try for LB above 2500 to test.

Today I noted:
ScanGauge "LOD" below 60 to go into LB.
Once in LB, LOD over 90-91 will put it out of LB.

Up till today I was using the TPS for same purpose,limits were 19 max to get LB and over 32 would end it. But the TPS limits actually vary with your rpm's, I think LOD numbers are a more consistent guide.

Awesome testing Bruce. I have been getting a check engine light for P1164 lately (main 5 wire O2 not reading properly.) Once I upped my RPM's and was going 70-75, I seem to get into lean burn just fine. Once in I can then lower my speed back down to 65 mph. I have a new O2 on order so know if it is the O2 limiting me, or the tall gears / low RPM's of the transmission.

Originally Posted by Jakins

Is LOD scan gauge talk for something?

LOD is a scan gauge abbreviation for engine load. It is a percentage of the maximum power available that is currently being generated to what is being used.

Originally Posted by Jakins

And is there any write ups on what to wire an led or gauge up to see when you are in lean burn?

Yes, I will post some links later today unless someone else beats me to it. As Bruce said, it is for a VX, but they use the same O2 sensor and technology.

Originally Posted by Jakins

I really hate to thread jack, I'm sorry haha. I'm just a really curious person. The car looks great with the HX wheels by the way. I'm surprised you opted to keep the a/c

Thanks. I want really high MPG, but don't want to give up AC. I also want to swap over the power windows and locks to have a few more "luxuries." Once that is complete I will probably put on a car alarm with keyless entry and a truck/hatch release. No remote start though… lol wasting fuel to get the car warmed up? NEVER!

[brucepick]

turbovr41991,

Tell me what rpm's your car needs to start and to keep lean burn. I suspect rpm's are the controlling factor and not speed. I might be able to advise you better with that info.

Also
Often it needs a few seconds at half or two thirds throttle to heat things up. Then if you drop back to max of 19 TPS or about 65 LOD it will then do LB after a few seconds.

And please do try some MMO (Marvel Mystery Oil) in the tank. Bottle says 4 oz per ten gallons, I'm recommending only 2 oz per ten gallons based on experience using it regularly since January 2012.

[turbovr41991]

Originally Posted by brucepick

turbovr41991,

Tell me what rpm's your car needs to start and to keep lean burn. I suspect rpm's are the controlling factor and not speed. I might be able to advise you better with that info.

RPMs seem to be best around 2500 @ 75 mph. Higher geared trans = higher speeds. MPG is suffering drastically to all this testing and going 70 to 75 mph all the time. This is making me want to do alot more areo to the car to help my gas mileage at these speeds and help stay in lean burn.

Originally Posted by brucepick

Also Often it needs a few seconds at half or two thirds throttle to heat things up. Then if you drop back to max of 19 TPS or about 65 LOD it will then do LB after a few seconds.

I will try this as well. Some times the coniditions are right for lean burn, but it does not engage. Could be why.

I just put in a fresh O2 sensor and was hoping that would help out. I am not getting the P1164 error code anymore, but not any noticable differences.

[brucepick]

Originally Posted by turbovr41991

RPMs seem to be best around 2500 @ 75 mph... ...

I just put in a fresh O2 sensor and was hoping that would help out. I am not getting the P1164 error code anymore, but not any noticable differences.

Yup. My HX also needed 2500 rpm for lean burn until I started using Marvel Mystery Oil. Now it runs lean burn down to 1800-1900 rpm. No I don't work for them and don't own stock or gain anything when others use MMO.

I've had the car 4 years now. Tried everything I could think of for over three years, including a head rebuild with four new valves. Still no low rpm's lean burn. One day after driving it 3.3 years I added MMO to the tank and voila, low speed lean burn and no more stress on that topic for me.

I anticipate a discussion of why it shouldn't work and it's snake oil, etc. Ho-hum. If I fill without it, I lose low speed lean burn. Then add some via a funnel and tube and it works again. I have guesses why it works but I don't care, as long as I don't run out of it.

[turbovr41991]

Picked some up and added between 2-4 ounces to the car (I know not the most ideal measuring, but enough to hopefully get some low RPM results. Will update on the drive home when I hit the highway.

Seemed to be 3.87 for a 32 ounce container at "wally world." That comes to under 25 cents per fillup if 2 ounces is used. Not bad especially since it comes with a long neck that allows for easy filling.

[turbovr41991]

The car did not seem better with the MMO on the first day, it actually seemed a little worse. Yesterday it seemed better and held lean burn for quite some time on the highway. At one point it entered it going 65 mpg, which is good for my current trend. I am running into a huge limitation that I have to be going 70-75 mph before getting in easily enter lean burn mode. It seems to enter between 2300 and 2500 rpm which is about the range for the speeds listed above in 5th gear. I have entered lean burn in lower speeds in other gears as long as the RPMs are around 2500, but this was only done for tests. The bulk of my up-shifting is done between 1700 and 1900 RPMs. Ultimately, I really need more Aero mods to be able to use lean burn effectively.
Today I was in a bunch of traffic and unable to go 70+ mph, so I decided to test out its DFCO ability. The reading on scan gauge seemed to be showing a little more delay than the CX engine/ECU, so I was a little concerned. Keep in mind I did not do any EOC. On trip today I averaged 52 mpg with a few long stops/ hard brakes and the other trip I averaged 63. The 63 was nearly perfect timing at lights and did not run into any major hiccups on the trip. So not even using lean burn, this engine seems more efficient in the lower RPMs. My lower speed sections of pulses seem to be brisker while not giving up valuable MPG in doing so. Perhaps tomorrow I will try a max mpg effort run rather than “testing.”

[brucepick]

It's coming back to me now - I went through this back in January so it's been a while. When I started using MMO I didn't have LB easily always, at first. I only noticed that it was easier to get LB and at speeds below 62 mph, and it got easier with more miles driven.

My big frustration before MMO was I needed 2300-2500 rpm to get AND KEEP Lean Burn. I had rarely seen LB below those rpm's. It only happened when the gods smiled on me. But things got a lot better through the first tank or two with MMO.

On the third tank I forgot to add MMO. No more low speed LB. I pulled over and added some, started back down the interstate, and after the requisite two miles I had low speed lean burn again.

To get into to LB you'll need:
Engine warmed up
Two miles driven at highway speeds
No EOC. That restarts the two miles "clock".
TPS below 20 or LOD below 65
RPMs ABOVE approx 2400 or 2500
RPMs above aprox 1800, after MMO has cleaned up whatever it cleans

To KEEP LB you need:
RPMs limits as above, depending on if system is using MMO or not.
TPS below 32. Below 29 at slower speeds. (is a sliding target)
OR - LOD below 92, pretty much regardless of speed.
That's why I like LOD now. More consistent to use.

S-L-O-W increase in pedal depth (throttle) after you get LB, or you can lose LB. Once you get experience you can more easily push down accelerator to its LB limit after going into LB, without losing it.

GOOD LUCK! More miles with MMO = easier LB, at least for my car.

[Jakins]

So if you stay below 20tps and above 2400 rpm on the freeway for 2 miles it will turn on by itself? I'd like to see if mmo works for turbovr4 an if it does I'll give it a try. Was anyone able to find the led light thing? I have a narrow band a/f gauge. Would that be able to give me an idea if I am in LB? Also I was reading on here and I saw that the HX can do lean burn regardless of the second o2 sensor and the stupid restrictive cat? Because a long time ago I had headers and no o2 plugged in and I got pretty decent mileage before I was a hyper miler. I'd like to try something like that again. But I'd have the o2 plugged in this time. Maybe out spaced a little outside of the direct flow of exhaust.

[brucepick]

Originally Posted by Jakins

So if you stay below 20tps and above 2400 rpm on the freeway for 2 miles it will turn on by itself?...

Good that you asked:

You only need TPS 19 or lower when you actually want it to go into LB. Before that over the two miles, just don't stomp on it. And once you get it into LB you use the second set of rules (shorter set) to keep it in LB.

Also - and I left this out before - coasting in gear with foot off the accelerator seems to disable lean burn even if you already had it. Coasting in neural is OK, you will be able to get LB back after maybe 5-30 seconds of following the other guidelines.