Hummer H2 - How Can I Get Better MPG & Reduce Emissions?

[Telco]

Need to check into the details on your trans with the dealer. Ask them about the lockup points and what gears. Not all transmissions will have a 3rd gear lockup.

[HummerH2]

MPG went down to 12.7 in city. My wife is still trying to get used to the new driving behavior. I am sure it will take her a couple of weeks to get a handle of it.

I have asked her to use the car only if needed.

As for the question of where I live, I am in Northwest Arkansas.

I am seeing good solutions on making changes to the car but I am not as savy on cars as most of you. It may have to be explained to me in a more simple and detailed manner.

I appologize for my lack of knowledge on the car convertion (mechanical changes) area.

Thanks for the support!

[savoF3]

Hmmm, this is what I found on my tranny on allpar.com.

In the A604 and 41TE, lockup can occur in both third and fourth gears (and second under special conditions) between 27 and 50 mph, depending on engine load and throttle position.

27mph was lower than I thought. And according to the manual putting the lever in '3' just disables O/D. There's no 'trick' in putting it in '3' to enable lockup below 4th gear.

[CoyoteX]

On a GM 4l60e/65e car I know that between 35 and 44mph the converter won't lock up in OD but if you pull it down to 3rd it will lock up above 35mph. In OD it locks up at 45mph. It unlocks any time when you give it more than about 1/4 throttle.

My Camaro had those settings in the factory tune. A Monte Carlo and GMC Sierra I drive pretty regular also seem to be programmed pretty similar in how they handle the lockup functions. None of them will stay locked up in OD below 40mph. But will stay locked up in 3rd down to 30mph. The GMC has the tow mode button and it modifies the shift points and lockup but I am not sure how the tow mode is configured.

I still think the easiest thing would be to have a light that comes on when the converter is locked so you can always adjust your driving style to keep the light on as much as possible. I wonder if there is a setting in the scangauge that can show when the converter is locked up?

[HummerH2]

Originally Posted by Coyote X

On a GM 4l60e/65e car I know that between 35 and 44mph the converter won't lock up in OD but if you pull it down to 3rd it will lock up above 35mph. In OD it locks up at 45mph. It unlocks any time when you give it more than about 1/4 throttle.

My Camaro had those settings in the factory tune. A Monte Carlo and GMC Sierra I drive pretty regular also seem to be programmed pretty similar in how they handle the lockup functions. None of them will stay locked up in OD below 40mph. But will stay locked up in 3rd down to 30mph. The GMC has the tow mode button and it modifies the shift points and lockup but I am not sure how the tow mode is configured.

I still think the easiest thing would be to have a light that comes on when the converter is locked so you can always adjust your driving style to keep the light on as much as possible. I wonder if there is a setting in the scangauge that can show when the converter is locked up?

This is a great idea about the light. It will help my wife quite some! How could I do this?

[HummerH2]

I have found somenthing very interesting. Using Shell vs. any other gasoline makes me improve MPG.

Does this make sense at all?

[landspeed]

Hummer H2

Congratulations on your gas-saving - it sounds like you have been doing a lot of gas-saving, what with the car-pooling and your wife using the car with efficient planning of journeys

And on top of all that you have now started to do hypermiling - that is really good!.

In the UK, my car gets worse mileage than most newer petrol cars - but now I'm getting close to / above a Toyota Prius mileage (if driven normally). I'm sure you can save a lot of gas in the Hummer - if you get 20MPG, that will be the same as many much smaller cars!

Monitoring your fuel economy
----------------------------

(1) Use the instant fuel economy gauge to track your driving habits and change them 'on the fly'.

(2) For the gaslog - note the odometer mileage, and fill up the the brim. After this, wait till you have used at least half a tank, then fill up again. Note the difference in mileage, then just say MPG = miles/gallons, and that will give you the true MPG. Put the figures (of gallons used, and miles driven) into your gaslog - then you can see what difference your changes have made.

Every time you fill, it will 'click' off at a different level. This introduces random error, but this gets less if you wait longer before refilling so you can get more fuel in.

Aim for 20MPG - it will be possible but difficult. In your car, aerodynamics will make a big difference, so remove the roofrack if not in use, and consider 'normal' rather than off-road tyres. Increasing the inflation in your tyres will also help, although be careful that you don't disturb the handling, as you don't want to put your wife in danger. Also, don't inflate them over the PSI limit, or they might fail.

If your fuel economy gauge only shows an 'average' rather than instant, then get a SuperMID (or Scangauge if you have an OBD-II port, which you should). Instant MPG, got my mileage from 42mpg TO 52mpg on the first tank . And my car is rated at 22mpg.

Good luck, welcome to gassavers, and enjoy your stay (and please don't feel pushed away by the anti-hummer comments - as said above, if you sell it, it will just go to someone who probably gets 8mpg anyway, and also drives it a lot more than you (or your wife) do.

[GasSavers_Red]

Could simply be that the Shell gas has more detergents then an other station. So you engine gets a better "cleaning" using Shell then someone else. How many miles are on your H2? Might want to give SeaFoam a shot or try some acetone treatment.

[Hockey4mnhs]

i agree 100% with ryland i prolly do use more gas in a day then they do and thats all that matters.

[Telco]

Easiest way to hook up a lockup light would be to find the wire that the computer uses to command lockup. Install a relay, using the lockup initiating wire as the control wire. Use a normally open relay for this. Hook up a light on the powered end of the relay. When the computer commands lockup, it'll energize the relay, which will close the powered end, which will light the light. You'll need a good wiring diagram (not a Haynes manual) to find the correct wire for this.