lean fuel question
09-28-2008, 12:16 AM
#1
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Location: Aurora, Colorado
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lean fuel question
well, i got rid of some of the SES light problems, but now sometimes when im at a red light and the z28 is warm, the SES code will come on, but if i turn it off then back on, it goes away....?
I ground tested the car for codes and got 44 46, and 55, two with it being lean, and one security???
Im just throwing this out there, but I think the owner before had a cam put in it, and in which case i do not have a tune for...
oh yeah. the majority of the problem was the fact that i was using E85. Now im using E91+octane booster and it has helped. Thanks in advance for the imput!!
I ground tested the car for codes and got 44 46, and 55, two with it being lean, and one security???
Im just throwing this out there, but I think the owner before had a cam put in it, and in which case i do not have a tune for...
oh yeah. the majority of the problem was the fact that i was using E85. Now im using E91+octane booster and it has helped. Thanks in advance for the imput!!
09-28-2008, 04:50 AM
#2
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Location: Orange County, CA
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I'm not really sure what E91 is, but E85 is already 105 octane. I've never run E85 in my Z but considered it and did considerable research on the subject, and basically it comes down to higher octane but about a 28% less efficient burn rate, meaning you need 28%(+/-) more fuel to keep your engine running in closed loop mode. Some of my turbo buddies swear by the stuff, works better for them then some race fuels.
Most likely your ECU and/or Injectors can't flow that much fuel into the motor to keep up with the demand and you're running your engine dangerously lean and risking possible damage to your Cat. as well.
Do a quick search in google or wikipedia on E85 there's some helpful stuff there..
Most likely your ECU and/or Injectors can't flow that much fuel into the motor to keep up with the demand and you're running your engine dangerously lean and risking possible damage to your Cat. as well.
Wikipedia:
Operating fuel-injected non-FFVs (Flex Fuel Vehicle) on more than 50% ethanol will generally cause the Malfunction Indicator Lamp (MIL) to illuminate, indicating that the electronic control unit (ECU) believes that it can no longer maintain closed-loop control of the internal combustion process not due to the presence of more oxygen in E85, but rather the fact that E85 has less carbon per volume, thus requiring more than the injectors can deliver, than gasoline. Once the MIL illuminates, adding more ethanol to the fuel tank becomes rather inefficient. For example, running 90% ethanol in a non-FFV (Flexible Fuel Vehicle) will reduce fuel economy by 33% or more relative to what would be achieved running 100% gasoline. Even more importantly, continuing to operate the non-FFV with the Malfunction Indicator Lamp (MIL) illuminated may also cause damage to the catalytic converter as well as to the engine pistons if allowed to persist. To run a non-FFV with amounts of ethanol high enough to cause the MIL to illuminate risks severe damage to the vehicle, that may outweigh any economic benefit of E85.
Operating fuel-injected non-FFVs (Flex Fuel Vehicle) on more than 50% ethanol will generally cause the Malfunction Indicator Lamp (MIL) to illuminate, indicating that the electronic control unit (ECU) believes that it can no longer maintain closed-loop control of the internal combustion process not due to the presence of more oxygen in E85, but rather the fact that E85 has less carbon per volume, thus requiring more than the injectors can deliver, than gasoline. Once the MIL illuminates, adding more ethanol to the fuel tank becomes rather inefficient. For example, running 90% ethanol in a non-FFV (Flexible Fuel Vehicle) will reduce fuel economy by 33% or more relative to what would be achieved running 100% gasoline. Even more importantly, continuing to operate the non-FFV with the Malfunction Indicator Lamp (MIL) illuminated may also cause damage to the catalytic converter as well as to the engine pistons if allowed to persist. To run a non-FFV with amounts of ethanol high enough to cause the MIL to illuminate risks severe damage to the vehicle, that may outweigh any economic benefit of E85.
09-28-2008, 10:45 AM
#3
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Location: Engineerland
Posts: 1,517
If not tuned for e85 that is your problem. The computer can only add so much fuel and when it maxes the fuel trims out what you get is a lean fuel code. 26lb injectors will not supply even a basicly stock lt1 enough fuel at wot, and you will probably hurt the thing if you run wot without tuning on e85.
When you restart it, it goes into open loop mode again for a minute or two and ignores the fuel trims until a timer runs out.
You need a scanner and a substantial bit of tuning if you're going to run the car on e85. I have no clue how running a ton more octane would help you with a cam tuning issue you may or may not have.
When you restart it, it goes into open loop mode again for a minute or two and ignores the fuel trims until a timer runs out.
You need a scanner and a substantial bit of tuning if you're going to run the car on e85. I have no clue how running a ton more octane would help you with a cam tuning issue you may or may not have.
09-28-2008, 11:36 AM
#4
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Location: Aurora, Colorado
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yeah. I have stopped using the 85....and it seemed to be a lot better.
thanks for the imput!
EDIT: im sorry what i meant to say was the 85 octane not E85....
thanks for the imput!
EDIT: im sorry what i meant to say was the 85 octane not E85....
Last edited by Austin_78@msn.com; 09-28-2008 at 07:24 PM.
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