HCH Not Entering Lean Burn?
#1
08-24-2004, 04:06 PM
Hi, I'm a new member. I've been reading this great site for awhile and have used many of the tips here with great success on my 2004 HCH. I have a question about Lean Burn mode.
I recently took a short day trip from Eugene, OR to Portland, OR. It's about 120 miles along I-5, almost entirely flat and straight. On the trip up in the morning, the FCD averaged about 55-60MPG and everything was working as it usually does. I was driving about 65-70MPH (I know this is not the ideal speed for fuel efficiency, but I tend to fall "middle of the road" in the speed vs. efficiency trade off).
On the return trip in the afternoon, I was really fighting to have the FCD register 40MPG. I had backed off my speed somewhat (was going about 60-65MPH). I was hard pressed to figure out what had changed. My assumption was that (for whatever reason) the car wasn't entering Lean Burn mode (I'm assuming Lean Burn is when I'm cruising at a stable speed and the FCD will jump up to around 60MPG). Whenever I forced the FCD to about 50MPG, I would slowly (and continuously) loose speed. This was very different than the car's usual performance, and certainly different that the morning's trip up.
I can only come up with two possible reasons: 1) I did seem to have a fairly strong head wind on the return trip (which meant that I probably had a tail wind on the trip up). 2) There was a LOT of field burning going on during my return trip (as usually happens this time of year in the Willamette Valley). So much, in fact, that the air smelled quite smoky (I had to re-circulate the cabin air most of the time to avoid the smoky smell). Could the added smoke in the air cause that much decrease in efficiency?
My particulars: 2004 Honda Civic Hybrid, CVT, 2200 total miles. Econ button always on. I try to practicing the "drive with load" technique, rarely use cruise control or A/C. I bought the car on 6-9-04. Lifetime MPG is 46.5, current tank is 47.6. Factory Dunlop tires at 45PSI.
I've been quite happy with my car and realize that 40MPG is still a great number, I'm just curious about what could have caused the decrease in efficiency. Any info would be appreciated, and sorry for the long post. Thanks,
Garrett
gar1138
BTW, does anyone have any info about the particulars of Lean Burn mode? I think there was a thread about it at one time, but I can't seem to find it.
I recently took a short day trip from Eugene, OR to Portland, OR. It's about 120 miles along I-5, almost entirely flat and straight. On the trip up in the morning, the FCD averaged about 55-60MPG and everything was working as it usually does. I was driving about 65-70MPH (I know this is not the ideal speed for fuel efficiency, but I tend to fall "middle of the road" in the speed vs. efficiency trade off).
On the return trip in the afternoon, I was really fighting to have the FCD register 40MPG. I had backed off my speed somewhat (was going about 60-65MPH). I was hard pressed to figure out what had changed. My assumption was that (for whatever reason) the car wasn't entering Lean Burn mode (I'm assuming Lean Burn is when I'm cruising at a stable speed and the FCD will jump up to around 60MPG). Whenever I forced the FCD to about 50MPG, I would slowly (and continuously) loose speed. This was very different than the car's usual performance, and certainly different that the morning's trip up.
I can only come up with two possible reasons: 1) I did seem to have a fairly strong head wind on the return trip (which meant that I probably had a tail wind on the trip up). 2) There was a LOT of field burning going on during my return trip (as usually happens this time of year in the Willamette Valley). So much, in fact, that the air smelled quite smoky (I had to re-circulate the cabin air most of the time to avoid the smoky smell). Could the added smoke in the air cause that much decrease in efficiency?
My particulars: 2004 Honda Civic Hybrid, CVT, 2200 total miles. Econ button always on. I try to practicing the "drive with load" technique, rarely use cruise control or A/C. I bought the car on 6-9-04. Lifetime MPG is 46.5, current tank is 47.6. Factory Dunlop tires at 45PSI.
I've been quite happy with my car and realize that 40MPG is still a great number, I'm just curious about what could have caused the decrease in efficiency. Any info would be appreciated, and sorry for the long post. Thanks,
Garrett
gar1138
BTW, does anyone have any info about the particulars of Lean Burn mode? I think there was a thread about it at one time, but I can't seem to find it.
#2
08-24-2004, 07:09 PM
Garret,
Personally, i'd say that #1 would be the reason, though the smoke may have had the Emissions systems going "wha?". Just a though.
Cheers,
Steven
Personally, i'd say that #1 would be the reason, though the smoke may have had the Emissions systems going "wha?". Just a though.
Cheers,
Steven
#3
08-24-2004, 07:30 PM
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#4
08-24-2004, 07:37 PM
I thought the HCH CVT 2004 did not have a lean burn mode
??????
Or does it have lean burn but nothing on the dash to tell you that you are in lean burn like other models
?????
??????
Or does it have lean burn but nothing on the dash to tell you that you are in lean burn like other models
?????
#5
08-24-2004, 08:41 PM
kenny,
The insight has "nothing" on the dash to tell you that you are in lean burn...as far as a *dummy* light goes. The way to tell however, the instantanious as i understand it, will jump up 20-40 mpg.
Cheers,
Steven
The insight has "nothing" on the dash to tell you that you are in lean burn...as far as a *dummy* light goes. The way to tell however, the instantanious as i understand it, will jump up 20-40 mpg.
Cheers,
Steven
#6
08-25-2004, 05:01 AM
Steven this spec sheet on Honda's website for the Insight says the Insight manual transmission has lean burn, but the CVT does not.
Look at the ninth spec from the top, the Multi-Point Fuel Injection:
http://www.hondacars.com/models/specificat...delName=Insight
Then the spec sheet for the HCH indicates Dual-Point Sequential (i-DSI) Lean-Burn Ignition System with Immobilizer for both the manual and the CVT.
What does all this mean?
Does the Insight CVT not go into lean burn?
And what is this immobilizer?
Look at the ninth spec from the top, the Multi-Point Fuel Injection:
http://www.hondacars.com/models/specificat...delName=Insight
Then the spec sheet for the HCH indicates Dual-Point Sequential (i-DSI) Lean-Burn Ignition System with Immobilizer for both the manual and the CVT.
What does all this mean?
Does the Insight CVT not go into lean burn?
And what is this immobilizer?
#7
08-25-2004, 05:35 AM
There's been speculation on this about the Insight. I noticed this same phenomenon -- that the Insight CVT is shown not to have lean burn -- when I looked at the brochure.
I don't think that the software on the Insight for the CVT is that much different; it might be that the CVT puts some added "drag" on the engine, and you just don't go into lean burn much, if at all. That would explain some of why the CVT doesn't get as good gas mileage as its manual transmission counterpart. They (Honda) might have just decided to say that it doesn't have lean-burn, just to get around that fact.
If you translate this to the Civic Hybrid, with its bigger gas engine, it does have lean burn mode with CVT. It's been my experience, though, that the CVT doesn't enter lean-burn as often as a manual does, from my test drives. That's one reason I believe the manual gets slightly better mpgs than CVTs.
There's no indicator, however, that you are in lean-burn. Only the FCD (fuel consumption display, or instantaneous mpg meter) really shows it, by jumping 10-20 mpgs for no other reason (no downhill, foot off accelerator, etc). If you hold your foot steady on a flat road, you can actually "see" it cycle back and forth. At least, on mine you can.
Mark
I don't think that the software on the Insight for the CVT is that much different; it might be that the CVT puts some added "drag" on the engine, and you just don't go into lean burn much, if at all. That would explain some of why the CVT doesn't get as good gas mileage as its manual transmission counterpart. They (Honda) might have just decided to say that it doesn't have lean-burn, just to get around that fact.
If you translate this to the Civic Hybrid, with its bigger gas engine, it does have lean burn mode with CVT. It's been my experience, though, that the CVT doesn't enter lean-burn as often as a manual does, from my test drives. That's one reason I believe the manual gets slightly better mpgs than CVTs.
There's no indicator, however, that you are in lean-burn. Only the FCD (fuel consumption display, or instantaneous mpg meter) really shows it, by jumping 10-20 mpgs for no other reason (no downhill, foot off accelerator, etc). If you hold your foot steady on a flat road, you can actually "see" it cycle back and forth. At least, on mine you can.
Mark
#8
08-25-2004, 10:08 AM
Thanks for the suggestions and info. The more I've thought about it, I'm also leaning towards the head wind (and possibly the smoky air, as well) since the car has run fine ever since.
As for Lean Burn, it would sure be nice to have some sort of indicator to know, conclusively, that one was in Lean Burn mode. With a simple indicator, it would probably be easier to develop some techniques to stay in that mode longer, too. One can wish.
Garrett
gar1138
As for Lean Burn, it would sure be nice to have some sort of indicator to know, conclusively, that one was in Lean Burn mode. With a simple indicator, it would probably be easier to develop some techniques to stay in that mode longer, too. One can wish.
Garrett
gar1138
#9
08-25-2004, 04:31 PM
Kenny,
I think the imobilizer may be for fuel cut...maybe to stop the fuel pump from pumping?
Cheers,
Steven
I think the imobilizer may be for fuel cut...maybe to stop the fuel pump from pumping?
Cheers,
Steven
#10
08-25-2004, 04:50 PM
Hi Gar1138:
___Don’t worry about needing an indicator to tell if you are in lean burn or not. Just max the FCD at all times and you will be in lean burn more often then not. All HCH’s have lean burn, only the 5-speed in the Insight’s has it, and 1 regular Civic Coupe has it available today. As all have mentioned, when entering lean burn, you will see the FCD jump. You will also see the sag and the slight acceleration during the NOx purge but it is usually very short lived.
___Since you are a relatively new Hybrid pilot, you will begin to get the feel for her as more miles are placed. Whenever I see the FCD running a bit lower then expected, I look around at the trees, bushes, flags, or dust and debris on the road as it is being blown about by traffic in front. More often then not, these signs will tell you have a head wind even though not 5 miles before you actually had a tail or no wind at all. It ticks me off of course but in the grand scheme of things, just do your best using the FCD to teach and you will come out far ahead of the next guy … Head wind or not!
___Good Luck
___Wayne R. Gerdes
___Hunt Club Farms Landscaping Ltd.
___Waynegerdes@earthlink.net
___Don’t worry about needing an indicator to tell if you are in lean burn or not. Just max the FCD at all times and you will be in lean burn more often then not. All HCH’s have lean burn, only the 5-speed in the Insight’s has it, and 1 regular Civic Coupe has it available today. As all have mentioned, when entering lean burn, you will see the FCD jump. You will also see the sag and the slight acceleration during the NOx purge but it is usually very short lived.
___Since you are a relatively new Hybrid pilot, you will begin to get the feel for her as more miles are placed. Whenever I see the FCD running a bit lower then expected, I look around at the trees, bushes, flags, or dust and debris on the road as it is being blown about by traffic in front. More often then not, these signs will tell you have a head wind even though not 5 miles before you actually had a tail or no wind at all. It ticks me off of course but in the grand scheme of things, just do your best using the FCD to teach and you will come out far ahead of the next guy … Head wind or not!
___Good Luck
___Wayne R. Gerdes
___Hunt Club Farms Landscaping Ltd.
___Waynegerdes@earthlink.net
