In this video I have a look at a GMC 1500 4.8 with the Flex Fuel engine and according to scan data it is running rich... REALLY Rich! Pretty common issue with these vehicles and it is a really simple fix. So if you have a P0172 and P0175 be sure to check the alcohol composition first.
Important: The system is initialized by baselining itself on ASTM spec Gasoline (alcohol 0–10%). When an E85 compatible vehicle is built, an ECM or PCM replaced, or if the learned alcohol content has been reset with a scan tool, the fuel system will need to contain ASTM spec gasoline with 10% or less ethanol content. If the fuel in the fuel system needs to be drained and replaced with ASTM spec gasoline, the vehicle will need to run for approximately 11 km (7 mi) at full operating temperature before the system will be fully adjusted to the correct alcohol content. Once system initialization has been completed and the calibration verified to be the below listed calibration part number or later, gasoline with any ethanol content between 0 and 85% may be added, provided it is added in a quantity of 11 Liters (3 gallons) or more, and the vehicle is run long enough to learn the new fuel
After the re-fueling event, the system registers the amount of fuel that was taken on-board, relative to the amount that was in the tank. Reading fuel trim and O2 sensor activity, the system determines the ethanol content of the fuel that was added. Based on that determination, it adjusts itself to the expected alcohol mix in the fuel tank and lets the fuel trim and O2 sensor activity fine tune the adjustments. The system must remain in closed loop in order for this adjustment to occur. Numerous short trips after switching from gasoline to E85, or vice versa, can result in driveability symptoms due to the inability of the system to adjust for fuel composition (by not attaining the parameters necessary to reach closed loop operation)
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Due to factors beyond the control of South Main Auto Repair, it cannot guarantee against unauthorized modifications of this information, or improper use of this information. South Main Auto Repair assumes no liability for property damage or injury incurred as a result of any of the information contained in this video. South Main Auto Repair recommends safe practices when working with power tools, automotive lifts, lifting tools, jack stands, electrical equipment, blunt instruments, chemicals, lubricants, or any other tools or equipment seen or implied in this video. Due to factors beyond the control of South Main Auto Repair, no information contained in this video shall create any express or implied warranty or guarantee of any particular result. Any injury, damage or loss that may result from improper use of these tools, equipment, or the information contained in this video is the sole responsibility of the user and not South Main Auto Repair.
Important: The system is initialized by baselining itself on ASTM spec Gasoline (alcohol 0–10%). When an E85 compatible vehicle is built, an ECM or PCM replaced, or if the learned alcohol content has been reset with a scan tool, the fuel system will need to contain ASTM spec gasoline with 10% or less ethanol content. If the fuel in the fuel system needs to be drained and replaced with ASTM spec gasoline, the vehicle will need to run for approximately 11 km (7 mi) at full operating temperature before the system will be fully adjusted to the correct alcohol content. Once system initialization has been completed and the calibration verified to be the below listed calibration part number or later, gasoline with any ethanol content between 0 and 85% may be added, provided it is added in a quantity of 11 Liters (3 gallons) or more, and the vehicle is run long enough to learn the new fuel
After the re-fueling event, the system registers the amount of fuel that was taken on-board, relative to the amount that was in the tank. Reading fuel trim and O2 sensor activity, the system determines the ethanol content of the fuel that was added. Based on that determination, it adjusts itself to the expected alcohol mix in the fuel tank and lets the fuel trim and O2 sensor activity fine tune the adjustments. The system must remain in closed loop in order for this adjustment to occur. Numerous short trips after switching from gasoline to E85, or vice versa, can result in driveability symptoms due to the inability of the system to adjust for fuel composition (by not attaining the parameters necessary to reach closed loop operation)
If an SMA Video has helped you out please consider giving using "Patreon" to help support us. The videos take real time to create and pull us away from real work that pays our bills. CLICK HERE: https://www.patreon.com/southmainauto
THANKS A MILLION!!
--Eric O.
WANT AN "SMA" STICKER OF YOUR OWN!?!
Simply send and E-mail to SMAstickers @outlook.com including: your shipping address and e-mail address in the text, I in turn will send you a paypal invoice for $5 each USA or $6 each international. Let me know how many you want and as soon as the paypal invoice is paid I will ship them out ASAP! Thanks for your support of our channel!!
--Eric & Vanessa O.
Feel like sending some swag to SMA because you love the videos but don't know where to send it?
Just ship it here:
South Main Auto Repair
47 S. Main St
PO Box 471
Avoca, NY 14809
Disclaimer:
Due to factors beyond the control of South Main Auto Repair, it cannot guarantee against unauthorized modifications of this information, or improper use of this information. South Main Auto Repair assumes no liability for property damage or injury incurred as a result of any of the information contained in this video. South Main Auto Repair recommends safe practices when working with power tools, automotive lifts, lifting tools, jack stands, electrical equipment, blunt instruments, chemicals, lubricants, or any other tools or equipment seen or implied in this video. Due to factors beyond the control of South Main Auto Repair, no information contained in this video shall create any express or implied warranty or guarantee of any particular result. Any injury, damage or loss that may result from improper use of these tools, equipment, or the information contained in this video is the sole responsibility of the user and not South Main Auto Repair.
I had a throttle body relearn done to fix the constant problem after cleaning it. I think I may have made a mistake I did a fuel composition reset using X431 on my 2011 5.3 flex fuel suburban , currently have e85 in my tank. Now I have 2 code errors p0171-00 and p0174-00 fuel trim lean system lean bank 1 and 2. Did I do something wrong? I would appreciate any help what to do and proceed. Thank you
Appreciate that!!! Learned me something new
Hey you had mentioned most cheaper code readers can do this function. Is there any you can recommend. I just purchased one from Amazon and I made the assumption it could do this reset due to price. But it is not able to reset content. Mines at 62% and both long terms are pegged at -30
Alcohol is not your friend. My 2013 fifteen hunnert has the 4.8 and the same flex fuel sticker as your subject vehicle. Mine is also fahr ingin red but doesn't have a siren. More good info here stored in my memory banks should such a situation arise. I don't see any E gas available around where I live, but it was omnipresent during a recent trip into the heartland.
What happened the next time that customer filled up? I'm afraid that the next fill up it shot back up to 60-80% again.
2007 suburban.. it creeps up to 80% about every 4 months or so… then I've reset it… was up ? Bad o2 maybe?
My ltft is at 30 after I rest my achole
Eric: "That's why alcohol is dangerous"
Me on my 4th rum and coke while watching SMA: "Wooooooooow…. I feel attacked right now."
REV up the part canon
Hey Eric, ONCE, I thought I was wrong, but, I was mistaken
What is a good scan tool that I can use to do this without breaking the bank?
ethanol needs to be removed from all gas.
What type of scanner can I buy to do this reset myself and check my fuel alcohol levels
Great videos! What's your take on Catch Cans, do you like them for Chevys?
ERIC PO451 tank pressure sensor after market fuel pump GMC Sierra 1500 flex fuel that code keeps coming up after install 29 percent alcohol level have seen the evap solenoid code also PO446 which is not coming up now just the PO451 is this a bad tank pressure sensor on a crappy aftermarket fuel pump this is the second one installed under warranty if 5 volt reference is there what could it be causing this code other than a tank pressure sensor that is not working well on this fine GM product 🙄
My LTFT STFT are – 17… MAF 2.6 on idle and with ac on idle 3.5.. egr error 99.2 sometimes egr fluctuating even negative error… O2 sensor 1 no reading sensor 2 reading is .1 to .9… air fuel ratio commanded and measured fluctuating…
Didn't know they made FlexFuel 4.8s.
Cant scan tools read the vin from the obd2 port and cant it tell what the vehicle is from the vin so why do you need to tell it what the vehicle is
This is good. I’m my case this makes sense why the problem got better when they switched to E85 as well!
80% Alcohol must mean its been drinkin! And your bothering it when its on its hangover day! Whats wrong with you Eric? lol
Great video Eric O
the only reason the government wants alcohol in fuel is so you have to buy more gasoline per year. my car will get 150 miles more per tank of non ethanol fuel!!!!!
Well heck that was an easy fix to bad they're all not as easy as this one. Good information about flex fuel GM's
Eric, how many scanners do you have in the shop? Wich one has the larger range of makers?
You the man….
Pretty country!
i wonder if the MAF or other things they parts cannoned was actually faulty, making it calculate way off, then never drove it long enough at once for it recalculate..
Clearly the truck was drunk!
Had same problem on my 09 Silverado. Alcohol content was in the 30s when I run 91 pure gas since new. Had my mechanic disable comp data sensor. I will never run any ethenol in it. No more problems and get more mpg!
I didn't know you could get a tech 2 outside the dealership.
Love the "Parts-cannon" reference. We need an official SMA Parts Cannon Shirt!
😅🤣😂🥴🤣😅😅😂😂🤣😂🥴😂😂😂👍👌🤣😁 the cruising around music
I have shown your old video with the same prob to customers and let you explain what the prob is and not to top off the fuel tank as often as they do. Thanks for all the info and entertainment
Got this on 2015 Silverado, cleaned maf and throttle, boom issue gone
Thanks Eric. Love your videos – subbed and liked.
Best move putting the oem maf back and changing the oil. She's on the mend already, probably perked up on hearing the c/w track. Looks a well maintained neighbourhood with trees and shrubs.
Tech 2! I'd recognize that ugly beast anywhere!
Shivvy, keepin the lights on at SMA since 1938
Curious what makes the truck think it’s getting ethanol when it’s actually getting regular gas?
I had the 172 and 175 codes intermittently on my 2014 Silverado 5.3 GDI and the first thing I looked at was the fuel composition. It was at 6%. fuel trims were off the charts, both banks ltfts = -35 and stfts = -30. MAF sensor not over reporting either. I isolated the PCV with no fuel trim improvments, then isolated the evap with the same results. The problem disappeared a few weeks later and has not recurred. I am open to suggestions as to what would cause this
My muffler bearing is loud I spayed a whole can of wd40 in the tail pipe I didn't help what oil should I use its a ford
I wonder if some of the Ford flex fuel vehicles can have similar problems? Twice now in the last few years I have had rich codes on my 2004 4.0 ford sport trac and had slight rough idle. After doing the usual MAF cleaning and other things and not solving my problem I watched Eric O's earlier vids about resetting the computer and that has fixed my problem both times.
I have been guilty of regularly topping off my tank a few bucks at a time and also would sometimes run some E85 for the heck of it.
Water in the gas from a bad refuel station can trigger that. Usually I just add octane booster to a full tank and it goes back to normal. Does not always work so I say just reset it like he recommends
Oil can cause fuel trims to screw up??
Got the blow module in there
Why did this need the reset? What made it change to an incorrect setting? If the customer cannot easily reset this him/herself, then this is a truly awful system. Will it reoccur if the root cause is not addressed? This one left us hanging Eric….
Good to know, I have a Flex-Fuel 05 Avalanche with approx. 130,000 miles. Never had a problem with the Flex-Fuel system or the eng not running properly. I try to run E85 as much as possible in her she drinks a lot of alcohol 🙂
o change oil service tire monitors just the typical for Chevys lol
After the warning about alcohol , a smooth transition would be a belch.