My 2nd Honda Insight

[mpg_numbers_guy]

Hm. My Insight can lean burn up to 72 mph on level ground at ~80 mpg in the summer. Haven't driven it that fast in the winter but I doubt I'd be able to maintain speed while lean burning in the cold. I wonder what's causing lean burn not to work well for you over 40 mph? Is this the case with both of your Insights?

[Gasoline Fumes]

I couldn't tell you how my other Insight drives.
I could try its ECM, but I doubt that's the issue.

[Gasoline Fumes]

145/65-15 Yokohama Ice Guard IG20 snow tires on Honda Civic donut wheels. No change in tire weight, but the wheels add a total of 34 pounds!

[Natalya]

Oh gosh you're in winter hell with heavy wheels. No wonder your car is struggling.

What I did when I lived in Ontario was I got a set of Civic VX rims with all seasons on them. But it would be better if you got snows on them. The lower rotational mass on the VX rims helps counteract the fact that the tires aren't low rolling resistance.

Getting the missing aero taken care of will help too but the wheels are definitely what's killing your ability to stay in lean burn.

If you have time to read 6 pages of posts I talked with the guys on Insight Central in 2016 about this same issue. I also made a new post today about using 4th gear in lean burn, but that still might not help because of those heavy wheels.

[Gasoline Fumes]

Originally Posted by Natalya

Oh gosh you're in winter hell with heavy wheels. No wonder your car is struggling.

What I did when I lived in Ontario was I got a set of Civic VX rims with all seasons on them. But it would be better if you got snows on them. The lower rotational mass on the VX rims helps counteract the fact that the tires aren't low rolling resistance.

Getting the missing aero taken care of will help too but the wheels are definitely what's killing your ability to stay in lean burn.

If you have time to read 6 pages of posts I talked with the guys on Insight Central in 2016 about this same issue. I also made a new post today about using 4th gear in lean burn, but that still might not help because of those heavy wheels.

I read the first and last page. I'll have to experiment with 4th gear more. I just put the winter wheels on, I was complaining about the car with RE92s at 60-65 PSI. I'm assuming the bucking at part-throttle has something to do with the MPG issues.

[Natalya]

If it's still bucking after EGR plate clean you might need a new EGR valve as well.

You want the Dorman one with part number 911-756

You want to avoid most of the EGR valves out there. Most of them have a smaller opening which can cause you to get P1491 check engine light because the passage is too narrow.

I haven't tried this one but the valve passage looks to be the same as on the Insight, maybe this one works fine:

https://www.ebay.com/itm/GENUINE-OEM...MAAOSw9a5XPrDx

It's cheaper than the Dorman I referred to above.

[iikhod]

Originally Posted by Gasoline Fumes

145/65-15 Yokohama Ice Guard IG20 snow tires on Honda Civic donut wheels. No change in tire weight, but the wheels add a total of 34 pounds!

Just out of curiosity, why the donut wheels?

[Gasoline Fumes]

Originally Posted by Natalya

If it's still bucking after EGR plate clean you might need a new EGR valve as well.

You want the Dorman one with part number 911-756

You want to avoid most of the EGR valves out there. Most of them have a smaller opening which can cause you to get P1491 check engine light because the passage is too narrow.

I haven't tried this one but the valve passage looks to be the same as on the Insight, maybe this one works fine:

https://www.ebay.com/itm/GENUINE-OEM...MAAOSw9a5XPrDx

It's cheaper than the Dorman I referred to above.

Thanks! Can the EGR valve be tested? I prefer not to buy parts unless I know I need them.

[Gasoline Fumes]

Originally Posted by iikhod

Just out of curiosity, why the donut wheels?

Normal 15" wheels would be too wide for these tires.

[Natalya]

If it's bucking in lean burn and you cleaned the egr passages then the egr valve is the main culprit. I'm not sure if it could be something else. I don't know how to test it unless you have a friend with an Insight and a good EGR valve you can try who lives near you. It's not super hard to pull the valve out.