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Discussion Starter · #1 ·
There is obviously a larger number of poeple who are not gettting the mileage they should out of their canyons. And there seem be also be a number of people who think these engines run rich, some have even claimed unburned fuel in the exhaust.

Could this be changed by spacing the MAF out of the airstream a bit similar to how the non-foulers are used to space the O2 sensors out of the exhaust?

Yes I understand the risks of an engine running too lean.

My question is would spacing the MAF out of the airstream lean out the mixture, and could that increase gas mileage.

Yes I also understand that some of this could be controlled with a Tune, but I can not find anyone near Minnesota to do one.
 

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I don't think it would have the effects that your after. To make it run leaner, you'd need a slightly larger maf tube.
Lime-swap.com could hook you up with a leaner mixture ($99 a flash) but I don't know if it would help much. To make real mileage gains, you'd want to target 16-17:1 and you can't really do that with the stock pcm.
 

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I don't think it would have the effects that your after. To make it run leaner, you'd need a slightly larger maf tube.
Lime-swap.com could hook you up with a leaner mixture ($99 a flash) but I don't know if it would help much. To make real mileage gains, you'd want to target 16-17:1 and you can't really do that with the stock pcm.
I really wouldn't even go that lean, these trucks are high compression. (10.5:1) I believe, correct me if i'm wrong. but going further than 14.7:1 would be one hell of a risk, ecp if you're going to be running anything less than 93 oct. Running hp tuners, I watched my truck knock above 4K RPM with 93oct. and 15 degrees of timing. but just my two cents.
 

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I really wouldn't even go that lean, these trucks are high compression. (10.5:1) I believe, correct me if i'm wrong. but going further than 14.7:1 would be one hell of a risk, ecp if you're going to be running anything less than 93 oct. Running hp tuners, I watched my truck knock above 4K RPM with 93oct. and 15 degrees of timing. but just my two cents.
Yeah, I certainly wouldn't want to run 17:1 without some serious tuning time.
You could probably do 15.5 safely, but how much would it improve fuel economy? And if you have to run premium, any savings is instantly lost.

The other problem is the narrow band O2. A NB O2 can't really tell the difference between 17:1 and 30:1 You could go REALLY lean and you wouldn't know until it's too late.
 

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if you look any colorado up, thus far, the ones i have hooked to PE is not even existent. PE delay is 8KRPM. and enrichment rate is .1 not a lot of fuel lost there. but also I have only hooked up to 3.5's so that could be a major diff to, but im willing to bet that gm did that with all of them, to conserve fuel economy.
 

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you would see NO GAIN! Don't waste your time. TB spacer's are overpriced but pretty paper weights!


Get a tune and get her done right. You won't regret it.
 

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you would see NO GAIN! Don't waste your time. TB spacer's are overpriced but pretty paper weights!


Get a tune and get her done right. You won't regret it.
I think the OP is wondering about moving his MAF, not a throttle body spacer. Seems the intent is to move the sensor out of the centerline of the intake tube so the velocity of air racing across the sensor wire is tricked into thinking it has a lesser amount of air coming through the intake.
 

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if you look any colorado up, thus far, the ones i have hooked to PE is not even existent. PE delay is 8KRPM. and enrichment rate is .1 not a lot of fuel lost there. but also I have only hooked up to 3.5's so that could be a major diff to, but im willing to bet that gm did that with all of them, to conserve fuel economy.
Just spot check an 07 and 08 - same results. The kicker is the TPS enable value of 94%. The way they set these things up, you never get 100% TPS.

I figured this out on the 06+ Trailblazers (when we inherited the P12 PCM) and people didn't believe me! :)
 

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badlandindustries.com
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Discussion Starter · #14 ·
xkmacx86 Thanks for the works of encouragement I have look at all those things previously, see my comments below. I am open to your opinions on my thoughts.

Manifold cat delete: Considering it, I have done it on all me other trucks, and I have never seen in improvement in gas mileage. I have read a lot of threads on this topic on 355 nation, and everyone says they love the extra power, but has anyone seen and increase in gas mileage?

Servos: Done

Wheel hop: not and issue

Sparkplug spring delete: done

Resonator Delete: I have read a lot of threads on this topic on 355 nation, but only one person stated an increase in gas mileage, and I beleive 2 have stated a decrease?

Engine filter: Don't think it will help mileage

New iridium plug and clean throttle body: Done

Ported Throtte Body: $$ and not sure I would see in increase in mileage.

Has anyone actually seen in increase in mileage with Cat delete, or resonator delete? How about by replaceing O2 sensors?
 

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Discussion Starter · #15 ·
PE is effectively disabled? I am not familiar with PE.

I am also a little fuzzy on how tricking the computer into running the truck a little leaner than stock (which everyone sees to agree runs rich), could have an impact on compression ration.

I am open to any knowledge impart.
 

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PE is effectively disabled? I am not familiar with PE.

I am also a little fuzzy on how tricking the computer into running the truck a little leaner than stock (which everyone sees to agree runs rich), could have an impact on compression ration.

I am open to any knowledge impart.
We were referring to the air fuel ratio. The chemically "perfect" mixture of fuel to air is 14.7 parts air to 1 part fuel by mass. You can change that in a tune, but we're not sure if it actually help all that much because you're limited by other factors.

Tricking the MAF is an exercise in futility anyway. Even if it did work -lean out the mixture- the O2 sensor would correct for it and you'd be back where you started.

My personal feeling -and others here may disagree- is that you could run a mixture as lean as 15.5:1 with no ill effects. NOx emissions would be slightly higher, but your fuel economy could potentially improve by 5% or so.

PE is Power Enrichment. Even though 14.7:1 is ideal chemically, you actually get best power at ~12:1. Most cars enrich the mixture under heavy loads for better power. The 355/360 trucks do not, so there's nothing to gain there.

If I were going to attempt a fuel economy tune, I'd set target AFR to 16:1 or so and try to set it so that you're in PE under almost any load greater than cruise.
 

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My tune had my motor set at 12:1 and I'm getting 300mi. granted short of forced induction I've done pretty much all that can be done to gain mpg.

In regards too the res delete it's a step in the right direction but not enough imo. I've built quite a few intakes for these trucks and I'm of the opinion they work better than the aftermarket CAI's.

All in all it comes down to how you drive and the terrain around you
 

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Just my 2 cents but I was getting about 300 a tank. Replaced the spark plugs cleaned the TB and know I'm back up to when I first bought the truck almost 450 a tank. Tune ups do help. Like I said just my 2 cents.
 

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tinja nurtles
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while PE is not used - there is more than one way to skin a cat... piston protection is enabled at 3200 rpm which i believe commands 10.1 based on something i read a while back


which begs the question - us there a tps threshold for that event or is it solely rpm based?



the truck most defiantly adds fuel when you romp on it but that is not what the op is asking. the fuel trims will level everything back out if you move the maf location out of the stream. so short of a tune there is no way to change target afrs
 

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tinja nurtles
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im on e85 so its a little different (stoich ~9.7) but i have stoich at 10.0 and it is working very well. so well im going to pull it up more. just remember to make the reverse changes to the PE tables so that you do not go lean under WOT
 
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