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Cpdfrank
Joined: 07 Oct 2010
Posts: 4
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 Posted: Thu Oct 07, 2010 7:50 pm Post subject: Accidentally put E85 in my 2006 Chevy Trailblazer |
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| By mistake I put approximately 10 Gallons of E85 in my Trailblazer. My vehicle had about 10 gallons of regular gas in it. After driving about 7 miles, the check engine light came on. Is there a need for immediate attention on my vehicle, or can I drive it until i'm almost on empty, and then fuel it up properly. Any information would be of great help. Thanks. |
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Alcohol
Joined: 17 Apr 2007
Posts: 634
Location: Central Wisconsin
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| Posted: Thu Oct 07, 2010 8:34 pm Post subject: |
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Been there-done that! So used to puttig E85 in my FFV's that I have done this myself with my other stuff. And I have intentionally done it at other times for testing. You have less than 50% alcohol in the tank since E85 has no less than 15% gas in it already. I would not be afraid of this but also do not like running with a check engine light since it can mask real problems like belt off etc. Most likely you have a CEL for "lean code bank 1". It is likely not running lean except on cold start and possibly at wide open throttle (WOT) when passing someone or climbing a steep grade because that it where the computer (pcm) uses a fuel map rather than reading the O2 sensor. Thus- it is best to not go WOT until you get some more gas in the tank.
The safe way is to top off with gas as soon as you can put in 3-5 gal and do it again each time some more will fit until you get the tank contents down to 20-30% alcohol. Your vehicle's PCM is more sensitive than either my 1996 Silverado which has even pulled a heavy trailer on a tankful of E60 or the 2000 Yukon I had that I mistakenly filled to 60+% before going on a trip- neither set a CEL. My Saab PCM is programmed with a narrower fuel trim limit and it will set a code at about 38%. All non-FFV vehicles are different- some can run full E85 without setting a code and others will set a code as low as 30%.
You have done nothing more than clean the gunk out of your fuel tank at this point- just do not drive aggressive until you top off this tank and get the alcohol % lower. If you live where it is cold- the next cold start may experience a stumble and die- if so- key it off and wait several seconds before trying it again.
A GM dealer will normally want to drain the tank and refill with gas- i feel this is overkill but they want to make sure you do not experience a cold start or go WOT pulling a trailer if lean- they play it extremely safe. You could go to a car parts store if you are nervous and have them put a scan tool on it to confirm it is just a lean code and not sometime unrelated and more serious. If it is a lean code- this will normally clear itself several miles or a drive cycle after you have brought the alcohol % down to where the long term fuel trims (fuel called for over the base map rate) have come down within standards.
I am just guessing here- your Trailblazer is a 2004 or newer? |
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Cpdfrank
Joined: 07 Oct 2010
Posts: 4
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| Posted: Thu Oct 07, 2010 8:44 pm Post subject: |
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| It's a 2006 Trailblazer |
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Alcohol
Joined: 17 Apr 2007
Posts: 634
Location: Central Wisconsin
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| Posted: Thu Oct 07, 2010 9:01 pm Post subject: |
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| Cpdfrank wrote: | | It's a 2006 Trailblazer |
That is what I thought- seems like GM "tightend" up the fuel trims around 2004 likely for the EPA's emissions rules. I suspect they want the fuel trims closer to the base fuel map to make sure that excess NOX emissions could not happen. Most CEL's are emissions related and in this case of lean code- it is not likely actually running lean but the PCM predicts it is possible and sets the code based on math rather than the O2 sensor not really keeping things in balance.
Which engine? |
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Cpdfrank
Joined: 07 Oct 2010
Posts: 4
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| Posted: Thu Oct 07, 2010 9:10 pm Post subject: |
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| 3.4L. V6 |
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Alcohol
Joined: 17 Apr 2007
Posts: 634
Location: Central Wisconsin
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| Posted: Thu Oct 07, 2010 9:44 pm Post subject: |
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I am not real familiar with that one. I am guessing that your code set after you did a hill climb or had to accelerate more than a light/very moderate level. A 3.4 L has to work fairly hard in a Trailblazer. The Implala FFV i drive has a 3.5L and had a 3.9L option. Interestingly, a newer style FFV will drive up to 5 miles after switching from gas to E85 before it "decides" which fuel you have put in- in the meantime it works similar to what yours is already doing- running on the O2 sensor readings and adjusting fuel upwards over the gas fuel map in the PCM. After it decides which fuel you put in (added programming does that) it will then select alcohol map (also added programming) so that when you do a cold start or go WOT there will be planty of fuel for full power and safest operating parameters.
Ethanol burns very cool and has extremely high octane (E85 is 105+)- this makes it more tolerant to lean condition that would burn an engine down quickly on gas. In a high performance application with high loads however- it is never advised to burn lean even on alcohols because a little bit lean can still build too much heat such that preignition could occur. |
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Cpdfrank
Joined: 07 Oct 2010
Posts: 4
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| Posted: Thu Oct 07, 2010 9:53 pm Post subject: |
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| Thanks very much for the information, and help. I really appreciate it. |
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Nwayne
Joined: 22 Mar 2010
Posts: 30
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| Posted: Wed Oct 13, 2010 12:44 am Post subject: |
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I accidentally on purpose put E85 in my 09 silverado all the time. I can usually put around 9 gallons in before the ck engine light comes on, then I just take it easy for a few miles, top it off with couple of gallons of regular gas and good to go.
_________________
64 Nova 2 Dr HT
350 SBC, Brodix IK200, Edelbrock E-Froce Supercharger 5psi, Horsepower Innovations E85 750 Carb, TH350, 3:55 posi
Runnin on Corn |
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Towlieee
Joined: 04 Oct 2010
Posts: 3
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| Posted: Wed Oct 13, 2010 11:58 pm Post subject: |
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| Nwayne wrote: | | I accidentally on purpose put E85 in my 09 silverado all the time. I can usually put around 9 gallons in before the ck engine light comes on, then I just take it easy for a few miles, top it off with couple of gallons of regular gas and good to go. |
Curious why you would do that?
Is your car notorious for running rich from the factory?
Higher octane doesn't gain you power unless you advance timing/increase compression to make use of it... Not to mention ethanol makes less power then regular gas (unless of course you mod your vehicle to make more power for the fuel you run)
I could see it in a older vehicle, like my honda prelude, they run extremely rich from the factory..
but don't most new vehicles run slightly lean from the factory? I know motorcycles are like that for emmisions, they already are lean right off the showroom floor, last thing I'd do is lean them out more by adding e85!
If you are doing it for fuel economy, how much does e85 cost where you live right now? Around my area, north west missouri, (well my only station in st. joseph missouri) its only 20 cents cheaper then 87 octane! It's AROUND 10% cheaper, but you burn 20-30% more, so people who run e85 lose fuel economy, and in a flex fuel vehicle, your better off running regular fuel at the moment.
I run e85 however for the octane myself, not the fuel economy. Just curious why you'd run so much to throw a check engine light. Seems kind of pointless? |
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hotrod
Joined: 19 Apr 2005
Posts: 872
Location: Colorado
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| Posted: Thu Oct 14, 2010 2:12 am Post subject: |
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| Quote: | | Just curious why you'd run so much to throw a check engine light. Seems kind of pointless? |
It is a quick and simple method of determining how much fuel trim authority your ECU has. The check engine light comes on when the ECU is using near its max fuel trim adjustment but still achieving normal fuel air mixtures.
With modern adaptive ECU's as long as the engine management system has fuel trim adjustment left, it will give you exactly the same light throttle fuel air mixture on ethanol added mixtures that you get on straight gasoline.
They will lean out on open loop but the high cooling power of E85 and its high octane provides enough cushion that it does not damage factory engines. High performance engines --- yes you should avoid going lean under full load but the minor lean out on a mixed blend is not a significant risk to typical street cars.
Since spark ignition engines are air limited for power, ethanol added fuels will actually produce more power than gasoline alone because you can burn more fuel with the same amount of air.
Due to the slight increase in power, lower heat load due to the cooler burn and better high load tolerance Ethanol blends give, many people get nearly the same fuel economy on ethanol blends as they do on straight gasoline. Most engines have a "sweet spot" fuel blend that gives lowest cost per mile. Blending until you get the check engine light is a quick way to find the maximum blend your engine can run and still have the ECU give normal fuel air mixtures. Then you take fuel consumption measurements at various points from there to a straight blend of gasoline to find the blend that gives lowest cost per mile.
A friend of mine had an old Ford pickup that he towed his racing motorcycles with, and he found it got the same fuel mileage up to a 60% blend of E85 and gasoline, which also gave him his lowest fuel cost per mile.
That of course changes according to the local split in prices between E85 and the recommended gasoline for your car.
For cars that require pump premium gasoline E85 blends are almost always the cheapest fuel in cents per mile even if the car gets lower fuel mileage in miles per gallon.
The national average regular gasoline price right now is about $2.86 / gallon, and the average price of E85 is about $2.41, if your car requires pump premium like my WRX the cost is about $3.06 per gallon, yet it will run just fine on a 50% blend of E85 and regular for a net cost per gallon of about $2.65 vs the cost of premium at $3.06. With that large of a price spread you can take a huge hit in miles per gallon and still come out ahead on cents per mile.
At 22 mpg on pump premium it costs about 13.9 cents a mile, on a blend of 50/50 E85 and regular at $2.65 a gallon and 20 mpg, the cost per mile is 12.25 cents. Since my car is setup as a full E85 conversion, I get about 19 mpg on straight E85 for a cost per mile of 12.7 cents per mile.
My sweet spot is around 70% blend of E85 with gasoline.
Larry |
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Nwayne
Joined: 22 Mar 2010
Posts: 30
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| Posted: Thu Oct 14, 2010 3:49 pm Post subject: |
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Just what hotrod said and it's .50 cheaper per gallon here.
_________________
64 Nova 2 Dr HT
350 SBC, Brodix IK200, Edelbrock E-Froce Supercharger 5psi, Horsepower Innovations E85 750 Carb, TH350, 3:55 posi
Runnin on Corn |
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Alcohol
Joined: 17 Apr 2007
Posts: 634
Location: Central Wisconsin
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| Posted: Thu Oct 14, 2010 7:28 pm Post subject: |
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Where I live E85 is 2.259 and 87 octane gas is 2.899. 90 octane is required for my '04 Saab and it would cost about 2.999 to 3.09. I put as much ethanol in the car as I can (E37-E38) without setting a CEL and have done so from the first tankful without any problems. Furthermore- during some long test runs on level interstate @ 70 mph (two different 1200 mile trips) I checked E30 vs E20 vs E0 premium and the car maintained 31.8 mpg on all 3 fuels each time.
Once the warranty is gone (100,000 miles- I am at 78,000 now) I plan to reprogram the ECU for full E85 as the pump and injectors are already large enough- the ECU programming for acceptable trims seems to be my sole issue (besides base maps for open loop).
E85 was $1.999 most of Spring and Summer. |
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