Is this lean burn in my HX?

[Daveedo]

Is this the famous lean burn?...
Cruising along at about 50mph when the car is up to operating temp it occasionally feels like it loses power and if I dont give it more accelerator pedal it loses several mph. To maintain the same speed I have to give it more fuel.

Sorta feels like when an A/C unit turns on while driving down the road...however, I don't have the a/c on.

[MetroMPG]

I've got limited experience driving a lean burn Honda, but yes, that sounds like it.

Opening the throttle more is one of the reasons lean-burn is efficient: it also reduces pumping losses.

If you search around, you'll be able to find instructions on how to hook up a digital multimeter so you KNOW for sure when you're in lean burn, because you really, really want to be in lean burn. The fuel economy is amazing.

Going to get an MPGuino?? That's another, more useful way to tell when you're in lean burn mode.

[NachtRitter]

Ya, I was going to say that what you are describing sounds like lean burn... I *just* installed the Fed ECU on my '94 Honda VX (It's originally a Cali model, and did not come with the lean burn feature from the factory, but a swap of the O2 sensor and the ECU with Fec VX parts enabled it), and I can definitely feel the change between normal and lean burn... That hesitation is the tell-tale...

Also just received the MPGuino, which I hope to get installed some time in the next month or so... as MetroMPG says, that should be able to tell me when I'm burning lean as well (via a jump in MPG, I would expect).

[Daveedo]

Thanks for the replies. I found that the HX's had a recall on the throttle cables that are sorta sticky. Mine is really sticky and ends up kicking me out of lean burn when I try to do a micro adjustment so I can keep the same speed so I guess I'll call the dealership soon about it.

[brucepick]

NachtRitter,
Please tell me about the MPGuino.

Is this something you can just order and "get"? I did some reading in the MPGuino subforum and it seems more like a 'figure it out' type project. But if you can buy one, that would be interesting.

ScanGauge:
I have a ScanGauge (SG) but it doesn't recognize lean burn in its mpg calculations.

Here's what's good about Scangauge for an HX:
1) You can program a ScanGauge XGauge to indicate LeanBurn. The cryptic procedure I'll put at the end of this post makes sense once you have the SG and the SG manual.

2) Throttle position (TPS) is key to getting it into LeanBurn and keeping it there. You can read TPS on the SG. If warmed up and weather is OK and the stars are properly aligned, TPS <20 will let it go into LB. If you go to TPS 32+, it will kick out of LB regardless of other conditions. TPS 30-31 is not always enough to maintain highway speed on a New England Interstate (hills and mountains) so it can be a challenge. If I recall, max TPS on my HX is 90.


XGauge procedure to set up LeanBurn indicator:
Use the code below to monitor lean burn with the scan gauge II
To Monitor Lean Burn, type in:
TXD 686AF10115
RXF 044105150000
RXD 2808
MTH 000100020000
NAM LBN
When it reads zero you're in LB.

[MetroMPG]

Brucepick: you can order a fully assembled, programmed & tested MPGuino from dcb: http://opengauge.org/mpguino/

NachtRitter: you're right about the way it indicates lean burn: the indicated instant MPG jumps pretty dramatically after the "lean burn stumble".

[Daveedo]

Originally Posted by brucepick

NachtRitter,
Please tell me about the MPGuino.

Is this something you can just order and "get"? I did some reading in the MPGuino subforum and it seems more like a 'figure it out' type project. But if you can buy one, that would be interesting.

ScanGauge:
I have a ScanGauge (SG) but it doesn't recognize lean burn in its mpg calculations.

Here's what's good about Scangauge for an HX:
1) You can program a ScanGauge XGauge to indicate LeanBurn. The cryptic procedure I'll put at the end of this post makes sense once you have the SG and the SG manual.

2) Throttle position (TPS) is key to getting it into LeanBurn and keeping it there. You can read TPS on the SG. If warmed up and weather is OK and the stars are properly aligned, TPS <20 will let it go into LB. If you go to TPS 32+, it will kick out of LB regardless of other conditions. TPS 30-31 is not always enough to maintain highway speed on a New England Interstate (hills and mountains) so it can be a challenge. If I recall, max TPS on my HX is 90.


XGauge procedure to set up LeanBurn indicator:
Use the code below to monitor lean burn with the scan gauge II
To Monitor Lean Burn, type in:
TXD 686AF10115
RXF 044105150000
RXD 2808
MTH 000100020000
NAM LBN
When it reads zero you're in LB.

NICE! Thanks for the info!

Originally Posted by MetroMPG

Brucepick: you can order a fully assembled, programmed & tested MPGuino from dcb: http://opengauge.org/mpguino/

NachtRitter: you're right about the way it indicates lean burn: the indicated instant MPG jumps pretty dramatically after the "lean burn stumble".

Hadn't spotted that yet, Thanks!

[brucepick]

Originally Posted by MetroMPG

Brucepick: you can order a fully assembled, programmed & tested MPGuino from dcb: http://opengauge.org/mpguino/...

That's tempting.
Gotta find a way to make it look pretty. Hopefully it's a standard size board that you can get a housing for??



I just now posted on Honda-Tech.com, asking where to find the speed sensor wire under the dash; I'd need to tap into that for MPGuino.

[thebrad]

Hey Bruce, hope these help




(Connector/Terminal: c117 | Number of Cavities/Color: 3 - Grey | Location: Right side of engine compartment | Connects to: VSS)

[1hondaman]

Bruce, thanks to you I have programmed my SG today for the Lean Burn mode. Now all I need to do is find some open road and see under what conditions it will engage.
I will come back when I have something useful to say.