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2007 and newer Chevrolet Tahoe and GMC Yukon



  • You are missing it completly. This is a hack/bypass for the Nav system NOT the engine computer

    This will allow you to play a video on the front screen as well as programing the Nav while moving.
  • OK...So who's gonna be the guinea pig on this one to see if it works and if so, how easy it was to install??

    I'm interested in this mod but don't want to be the first!!! :D
  • rockman59rockman59 Posts: 250
    To Sovereignmgmt: I thought you were replying to rwerner who was concerned with reprogramming his engine computer to increase his gas mileage. I understand that the hack/bypass for the Nav system is NOT the engine computer. Da!!!! I did go to the Nav sight and watched their little video. Very impressive....and all for $249.95.
  • It works great and it was a snap to install. In fact there is a video link on the install on there page.
  • I'd consider paying that amount if the hack included the ability to use the built in phone system with my current provider and phone. This is one of my biggest beefs with the vehicle, the fact that they didn't put in bluetooth and opted to force you to use Onstar or Verizon.
  • nosbor77nosbor77 Posts: 40
    Check out this article on GM Flex Fuel 1

    Maybe we can get AOL involved to do an article on their AFM fallacy
  • 73shark73shark Posts: 325
    That would make for an interesting article! Another problem with ethanol is that it takes more energy to produce than you get when you use it. :confuse:
  • catahoecatahoe Posts: 15
    Sorry thats just a rumor... Might have been true in the early days but not anymore
  • jay_24jay_24 Posts: 536
    The cost to produce is very much in question. Some say it costs more others say it costs less.
    Biggest issue currently is that most ethanol plants use the kernal of corn to make it. The next generation of ethanol plants will use the stalk, or grass, or other plant materials that are typically waste products today.
  • eliaselias Posts: 2,120
    hi! i really do mean that your vehicle uses zero fuel whatsoever when you are coasting in gear (foot off gas pedal!) - as long as rpm is above some minimum - 1000 or 1500 rpm maybe.
    this is the way fuel-injected vehicles have operated for at least 20 years - i not aware of *any* exceptions and would be awfully surprised if this new Tahoe is an exception.
    it would be counterproductive and wasteful for the ECM to pump any fuel during foot-off-gas/deceleration, as long as RPM is ~1000 or more.
  • jmaynardjmaynard Posts: 37
    Elias, I really don't want to insult you, but engines do not run without fuel. The 2007 Tahoe has an electric fuel pupm which is constantly feeding fuel to down the line to the injector system. During throttle operations, a valve is opened to allow 'MORE' fuel to flow to the injectors. Durig idle, or coasting, a steady mist of fuel is injected into the cylinders in order to keep the engine running. Without fuel, the engine will stop. This is a physical law and there is no way around it. Something MUST provide energy to make the crankshaft turn.
  • fundadfundad Posts: 27
    it would be counterproductive and wasteful for the ECM to pump any fuel during foot-off-gas/deceleration, as long as RPM is ~1000 or more

    What makes you think you can run an engine at 1000 rpm with out using gas??? If it didnt use fuel when coasting, the engine would simply shut off and you would no longer have power brakes or power steering. If you believe that there is no fuel being used during coasting... I have a 80 mpg carb to sell you for your new tahoo. lol
  • 73shark73shark Posts: 325
    If the fuel is shutoff when coasting, then why does the engine keep running when trans is put in neutral? :confuse:
  • 73shark73shark Posts: 325
    If that's so, then there are a lot of recent reports and studies that are wrong. Don't forget that the main reason Brazil can make it work is that they start with sugar. ;)
  • catahoecatahoe Posts: 15
    There are alot of bias and incorrect reports about E85 and any alternative fuels. Just look how many years now that oil has blocked any alternatives.
  • fundadfundad Posts: 27
    Another problem with ethanol is that it takes more energy to produce than you get when you use it.

    Not true!!! A by product of making ethanol is corn oil. Corn oil can be used to make biodiesel. If Ethanol uses ALMOST the same amount of energy to produce than what it can give, corn oil is ALMOST free then. I live in Minnesota and it has become VERY profitable to make ethanol now. Infact, there are 2 plants here that will be built that will produce more than 500 million gallons of ethanol each per year
  • 73shark73shark Posts: 325
    Here's a couple of articles that shed some lite on the rush to ethanol: - htm

    I agree that you have to be skeptical about these reports that support or not the use of ethanol. As an example, the same "scientists" that are now warning us about global warming were telling us in the 70s about the coming ice age and we would run out of oil in 20 years.
  • mobile1mobile1 Posts: 4
    Hello to all, When I purchased my new LT3 '07 Tahoe I was amazed when I raised the hood and noticed that there is not the typical cooling fan and fan shroud. This is the first design I have seen with an engine of this size without a constant cooling source to keep air moving through the radiator.I know Honda and majority of foreign cars use electronic fans but they are smaller engines and typically transverse mounted. I am concerned about in the event of a 2hr traffic standstill pulling the boat and the outside temp is pegging 100 will the electronic fans do a better job.Certainly a belt driven mechanical fan robs h.p.but they wont fail unless the belt breaks. I think we will need to keep and eye on these two electronic fans and make sure they dont freeze up. What are your thoughts. Oh yea, by the way are you guys buying your oil filters from the dealer? That's the only place I have yet to find them. AC PF48
  • steverstever Posts: 52,572
    Live green, go yellow, enjoy the subsidies. :shades:

    More in this collection of discussions: Ethanol - E85 FlexFuel
  • 73shark73shark Posts: 325
    I've had starters, alternators, and batteries fail. Have yet to have an electric fan fail. Always a first time tho. Haven't checked it out yet but I suspect that one fan comes on when needed and if it can't provide enough cooling, the other kicks in. Also one probably comes on whenever the A/C is on. Just a guess but based on previous GM cars I've owned.
  • sastokersastoker Posts: 11
    I installed a Gibson exhaust system (cat back) (P/N 615562) for my 07 Yukon on Friday 8/18. It is awesome. The sound is great and it doesn't sound nasty when you mash the pedal. The system fit perfectly and was a quick install. The hardest part was using a hacksaw to cut the OEM pipe out. I don't have a sawsall.
  • sastokersastoker Posts: 11
    My Yukon (5.3 4x4) with approx 8500 miles on it seems to hesitate a tad bit mid range in second gear when I floor it.

    Has anyone else experienced this?

    This past weekend I put an airaid intake and gibson cat back exhaust system on. I don't remember the Yukon having any problems before the mods. Then again, I never stomped on it. Before I take it to the dealer I though I'd give it a few more weeks.

    Is this the computer adjusting to the mods? Is it temporary? Any suggestions/comments?
  • Same filter issue here in upstate NY, the dealer is the only one carrying the PF-48 , my 2003 Tahoe with the same 5.3 used a PF-44, my 2004 Tahoe with the same 5.3 used a PF-46, and now the 2007 uses a PF-48. Seams to be a trend here. The dealer list is just shy of $11 each, I purchased a case (12) for $4.61 each, still higher than they should be.
  • mobile1 -
    It sure won't hurt to keep an eye on the fan situation, but I can tell you that they do work in traffic. I spent 2 hours going 10 miles yesterday with a trailer and Bobcat in tow (approximately 5000#) and the temp stayed in check without issue. :D
    On the filter situation, I have my local parts guy checking a couple different sources - but so far, he has hit a brick wall on availability. I've bought the last two from the dealer here. (sorry I couldn't be of more help on that one!)
  • jmaynardjmaynard Posts: 37
    You might want to try it without the traction control turned on. Sometimes the stabilitrack interfers with the acceleration.
  • eliaselias Posts: 2,120
    fuel is indeed shut off while decel/coasting-foot-off-gas, above certain rpm. as for question from 73shark, the engine keeps running when you shift into neutral because then the computer tells fuel-pump to pump a nonzero amount of fuel.
  • eliaselias Posts: 2,120
    hey there jmaynard. i am not insulted by you or anyone disagreeing with me. "i get a lot of that."
    your statement about engines is false. an engine can run just fine without fuel and have been doing so for a few decades if not more - they can run without fuel downhill, and/or with foot-of-gas coasting-in-gear-until-certain-low-rpm-is-reached.
    i am only talking about the vehicle being in-gear, foot-off-gas, rpm/speed above certain low threshold.
    there is no "mist" of fuel being injected in this 'deceleration' condition. zero fuel is injected.
    also your final statement about "physical law" is false. an engine will not necessarily stop without fuel, as long as you are coasting-in-gear with foot off gas, the engine will run indefinitely. if the "physical law" you state were indeed a law, every engine would seize up when the fuel supply ran dry! ouch!
    regarding your final case about "something" providing energy to make the crankshaft turn - YES - it is the kinetic energy of the vehicle which is being converted into energy turning the crankshaft. as long as the downhill is steep enough, this state can continue indefinitely.
    in the flat-road case, this zero-fuel-used condition will only last until the vehicle decelerates down to some low rpm & speed. when the rpm drops all the way to idle-speed, by then is when the fuel pump starts pumping a nonzero amount of fuel.
    hook up a diacom/OBD3-laptop to your truck and you can see for yourself (preferably while someone else is doing the driving/coasting-in-gear-decelerating-or-going-down-long-hill)
  • Hmmm - I find this rather interesting. I can only offer my observation to this, but here it is. On the zero fuel issue - if they are doing this with the newer fuel injection systems I think that is great! But I can confirm without a double that at least the throttle body versions used in the 90's did not go to zero fuel during coast deceleration, as I spent time working on both my van and my parent's van (with the cowl cover off) and can tell you that the only time that it did not inject fuel is when the key was off. Maybe this is something that changed with common rail and sequential injection but it definitely wasn't the technology applied in the early 90's on the throttle body injected G-20 and Astro vans.
    As to the zero fuel during coast, I know that at least with my '07, the initial let off of the gas does not generate any engine braking (it takes 10+ seconds of coasting before any engine braking starts), so I doubt that it is going to zero fuel, at least initially, during this condition as otherwise heavy engine braking would start immediately?
    One other thing to note on thezero fuel situation, and possibly this is being worked around with the use of the lock-up torque convertor, is without the engine driving the pump in the front of the transmission, the tranmission would be provided no lubrication and would loss line pressure resulting in the disengagement of the clutches holding the transmission in a particular gear. (this is the reason that you can't pull/push start an automatic) Now as I mentioned, it may be possible that this is being circumvented through forcing the torque convertor to remain locked up?
    Just some food for thought.
  • jmaynardjmaynard Posts: 37
    elias obviously has no idea how the internal combustion engine works. Gasoline and deisel engines do not run without fuel. ONce the fuel supply stops, the engine stops. Even when the vehicle is coasting fuel is being delivered to the engine and the engine remains running. Tuscotodd's comments are right on track. The torque converter in an automatic transmission does not lock when coasting in order to turn the crank on the engine. This action would reslut in damaging the shaft and the pistons and lifters. In order for te engine to remain lubricated, it must run. If it stops, so does the oil pump. In addition, the ac compressor is turned by the engine. If the engine stops, so does the AC. And last, but certainly not least, watch the RPM gauge when you are coasting. If the engine were stoppped you would experience 0 rpm's. Now, you may say that the 'computer' still shows rpms's becuase the engine is still turning due to this ficticious torque converter lock. To rebutt this, one must inderstand where the reading for the RPM gauge comes from. This device 'reads' the spark generated to the plugs. It the engine is not running, no spark is required, and no RPM's will appear. If you want to test this. put your car in neutral with the key turned on and roll down a hill. No RPM's, see.

    I have family members that have been in the auto repair business for over 80 years and, elias, you are dead wrong on this one.
  • jerrywimerjerrywimer Posts: 588
    I'll have to agree with you here. Either it's zero, or else a very small amount of fuel during the conditions you describe. I've actually done something that more or less proves this to be the case:

    I have a steep section of interstate grade I travel to and from work daily. Coming home I travel down this grade. With the 2004 Silverado I noticed that if I leave the engine running and in drive, the truck maintained close to 2000 rpms on the downgrade at roughly 60-65 mph. Knowing that the 5.3l idled at ~600 rpm, I figured that the truck would be more efficient if I put it in neutral on the downhill section. I watched the instant mpg readout on the DIC for two different trips and the truck actually reported (MUCH) higher estimated instantaneous readings for the trip in gear than the downhill run out of gear. Both runs were during different tanks of gas, so I had manually calculated averages to back up the experience. At the very least, less fuel is injected into the cylinders when coasting foot-off-throttle than is injected at normal idle despite the more than 3x RPMs.

    junglegeorge- On the PF48 fuel filter thing- the 07 Av takes the same filter. Same situation. I even suspected that maybe the filter from the 06 TB 5.3 might fit (it is also an AFM truck engine). It might, but the part numbers don't match. At the current time the dealership has a monopoly on filters for our 2007 SUVs. One other note about it- I'm not sure who quoted you ~$11 for the filter. I bought mine from a local Chevy parts department for just over $6. The bulk price you got still sounds better though.
This discussion has been closed.