Mooseman
Moderator
I'm not a believer of that. Fuel passes through the pump and there is splash around it. And there is that container around it that always holds fuel. They just fail no matter what.
Improving fuel economy
- Thread starter masospaghetti
- Start date
l008com
Member
I replaced all my lights with LEDs too, except my headlights. I tried a million different ones until I found ones that looked good, and were the proper brightness in both modes (brake and tail). That smaller electrical load should in theory reduce fuel consumption a tiny bit over time. And it looks much nicer.
My understanding is fuel flowing THROUGH the pump is what cools it.... a bath doesn't do much but flow does.... that's my understanding anyway.
Sounds like you are right on the money with that MPG . Same thing I get and I have RWD only .22-23 highway is the best you are going to do . It is a six but it is a big 6 . It is a heavy vehicle and it is only a 4 speed auto . I was always hopeful they would update that model and slap a 8 speed tranny behind that straight 6 and it would probably get 26-27 mpg . But they in their infinite wisdom just dropped this model and lost me as a customer after that as I did not want a Traverse .
I dont know what that little crap box they call a trailblazer is now but it is not a Trailblazer .
Mooseman
Moderator
And just another thought, there are the usual ways to save on fuel in general. Try to lump all your trips into a single one so you only go out once, drive at or below the speed limit on the highway or use back roads at a slower speed, avoid jackrabbit starts and accelerate slowly, remove as much stuff and the spare to reduce weight (may not be an option if you don't have AAA/CAA or are traveling), go on a diet (I lost 60 lbs and it was like removing the spare tire 
), carpool, keep tires aired up, use the A/C only when necessary, ensure the engine is running in top shape and tuned up, ensure brakes are working perfectly and not dragging.
For the A/C, realize that it will ALWAYS be on if you have the HVAC set to any position that has defrost on and it's above freezing temps outside. If you don't need defrost, don't leave it there.
Although this doesn't apply to @masospaghetti , one important thing, do not leave the transfer case in auto and use 2wd only. This will avoid having the driveshaft and transfer case spinning when it's not needed and reduce wear. If you never use 4x4, it may be worth it to just take out the axles, driveshaft and, if really serious, the front differential for the weight savings. If you're even more serious, you could remove the transfer case but you would have to replace the transmission or have it modified to 2wd and also finding or having fabricated a 2wd rear driveshaft.
For a tune, I don't know if there would be a lot of savings there. I found that I lost an MPG or two after my tune. I would think that the OEM would have made the tune as efficient as possible. You could have the PWM turned off in the TCC but savings there would be minimal however can help your TC last longer and reduce heat. I would talk with @limequat as he is our resident expert on tuning this engine.
Check for backpressure in your exhaust system. A plugged cat will kill your MPG.
One last thought, ensure your fan clutch is working correctly and freewheels when it's not needed and engages properly when it is needed. If it's locked up or even just has a lot of drag, it will suck gas like there's no tomorrow. Try unplugging it and let it run a while. If it's not locked up, see if you can stop it easily with a rag. To test it if it's working correctly, re-plug it and go here:
How to test the electro-viscous fan clutch
), carpool, keep tires aired up, use the A/C only when necessary, ensure the engine is running in top shape and tuned up, ensure brakes are working perfectly and not dragging.For the A/C, realize that it will ALWAYS be on if you have the HVAC set to any position that has defrost on and it's above freezing temps outside. If you don't need defrost, don't leave it there.
Although this doesn't apply to @masospaghetti , one important thing, do not leave the transfer case in auto and use 2wd only. This will avoid having the driveshaft and transfer case spinning when it's not needed and reduce wear. If you never use 4x4, it may be worth it to just take out the axles, driveshaft and, if really serious, the front differential for the weight savings. If you're even more serious, you could remove the transfer case but you would have to replace the transmission or have it modified to 2wd and also finding or having fabricated a 2wd rear driveshaft.
For a tune, I don't know if there would be a lot of savings there. I found that I lost an MPG or two after my tune. I would think that the OEM would have made the tune as efficient as possible. You could have the PWM turned off in the TCC but savings there would be minimal however can help your TC last longer and reduce heat. I would talk with @limequat as he is our resident expert on tuning this engine.
Check for backpressure in your exhaust system. A plugged cat will kill your MPG.
One last thought, ensure your fan clutch is working correctly and freewheels when it's not needed and engages properly when it is needed. If it's locked up or even just has a lot of drag, it will suck gas like there's no tomorrow. Try unplugging it and let it run a while. If it's not locked up, see if you can stop it easily with a rag. To test it if it's working correctly, re-plug it and go here:
How to test the electro-viscous fan clutch
Schurkey
Member
The guy lives in California.
There is NOTHING he can do to the computer tune that will be legal without undergoing a full CARB emissions cycle at huge expense and with a likely fail.
As is, he's already getting substantially better fuel economy than I am in my '03. If I see 19 on the interstate, I'm happy. 15--18 is more likely depending on wind and grade change.
There is NOTHING he can do to the computer tune that will be legal without undergoing a full CARB emissions cycle at huge expense and with a likely fail.
As is, he's already getting substantially better fuel economy than I am in my '03. If I see 19 on the interstate, I'm happy. 15--18 is more likely depending on wind and grade change.
Mooseman
Moderator
One way to get around that is to have two PCMs and swap it out once you pass smog. Not exactly legal but
Probably not between this and the inconvenience. Although I have heard that the fuel pump cooling thing is a myth and that it uses the fuel flow for cooling, not being submerged. The pump is fairly tall and it would start being unsubmerged even with a half tank or so. Not totally sure though.
Great point, easy to miss since the A/C will run continuously even if the button isn't pressed in certain positions. The A/C pump can use a lot of power so will definitely affect fuel economy (if the interior is hot the pump can easily pull 10 horsepower). Keep the mode setting to "vent only" or "floor only" and the A/C will stay off unless you push the button.
If it's a bright sunny day, consider turning off your DRLs - 100 watts of electrical power that ultimately come from your alternator and the gas tank.
Also, turn off your blower fan if you don't use it. It seems trivial but our vehicles use a resistor pack, meaning the fan circuit pulls full power no matter what fan setting you pick (other than 0). It was enough power to melt the +12v connector going into the resistor pack.
paul2005tb
Member
my friend has the new trailblazer (2021) she gets 28 mpg on the highway. It has a 1.3L engine and at 60mph it is operating at about 1700 rpm. That turbo is like doubling the displacement.
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l008com
Member
Turbo's are great however 1.3 x 2 is still only 2.6. It would need another doubling to get up to the virtual size of my 5.3
Also looks aside, the new TB has a towing capacity of 1000 lbs. Mine can tow something like 6600 lbs. Meanwhile, chevy is STILL making a true 2nd gen trailblazer and still not selling it in the US. Built on the 2nd gen Colorado frame. That would have been a GREAT SUV over the last 10 years, with a 3.6 V6 putting out basically the same power as the old 4.2. And with that new 2.7T, it would be even more interesting. But chevy only makes SUVs people don't want. But that's another topic entirely.
cornchip
Member
- Jan 6, 2013
- 637
Turbo's are great however 1.3 x 2 is still only 2.6. It would need another doubling to get up to the virtual size of my 5.3
Also looks aside, the new TB has a towing capacity of 1000 lbs. Mine can tow something like 6600 lbs. Meanwhile, chevy is STILL making a true 2nd gen trailblazer and still not selling it in the US. Built on the 2nd gen Colorado frame. That would have been a GREAT SUV over the last 10 years, with a 3.6 V6 putting out basically the same power as the old 4.2. And with that new 2.7T, it would be even more interesting. But chevy only makes SUVs people don't want. But that's another topic entirely.
Strong pass on the 2.7's (RPO L3B) at the moment. Seems they are having engine misfire DTC's from an exhaust cam follower failure causing abnormal cam lobe wear. All platforms are currently experiencing this issue. I'd wait for the next revision.
l008com
Member
Well it's all moot now anyway since the mid-size truck-based SUV in north america still does not exist.
cornchip
Member
- Jan 6, 2013
- 637
Interesting news from just the other day showing GM's interest in boosted 6 cylinder power plants.
https://gmauthority.com/blog/2022/05/gm-considering-turbo-six-cylinder-engine-for-trucks-exclusive/
https://gmauthority.com/blog/2022/05/gm-considering-turbo-six-cylinder-engine-for-trucks-exclusive/
l008com
Member
In a real vehicle, a 3L turbo would be fantastic. It might even be a bit too much for a colorado based SUV. A 2.5L turbo inline-6 might be a better fit for most people. Make it available with a manual 7 speed and i'm in love
Mooseman
Moderator
I have a 3.0L turbo diesel and it's fantastic. Great power and fuel.economy in a full size truck. Can't beat that.
l008com
Member
Yup. A gas version would still have tons of power and fuel economy without the hassle of diesel
I've seen some people make efforts at improving the aerodynamics of the underside. With an EV it's easier since there is no driveshaft or exhaust. Look at what Rivian does to the underside:
We can't do it so completely, but there is room for improvement. I would start by making a cover for the area behind the rear axle.
We can't do it so completely, but there is room for improvement. I would start by making a cover for the area behind the rear axle.