Gen III Flex fuel Write-up
TECH Apprentice
Joined: Jul 2016
Posts: 349
Likes: 19
I had this thread bookmarked for when I got this far, and have been looking at Flex Fuel Sensors. I see there are a couple with mounting holes (379, 394) but most don't have them.
Most of the pics I've seen on Flex fuel conversions just have them dangling off the fuel lines. Do the ones without mounting holes snap into a bracket, or what? I see a few 3d printed brackets on Etsy or eBay, but how does GM do it? If I'm pulling one at the JY, I assume there will be a bracket for it?
Jay
Most of the pics I've seen on Flex fuel conversions just have them dangling off the fuel lines. Do the ones without mounting holes snap into a bracket, or what? I see a few 3d printed brackets on Etsy or eBay, but how does GM do it? If I'm pulling one at the JY, I assume there will be a bracket for it?
Jay
Teching In
Joined: Jan 2021
Posts: 18
Likes: 4
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Teching In
Joined: Jul 2019
Posts: 2
Likes: 0
Have a stupid question but here goes. LS1 single turbo, not running any O2 sensors just wide band sensor and AFR gauge. Was thinking going down this flex fuel track but unsure if I'd be able to do this P01 flex fuel setup if I'm not running factory O2 sensors?
Are factory O2 sensors needed for the AFR change or will the PCM sort out the required AFR target dependant on what % ethanol content from flex fuel sensor using the new tuned VE table for 98 fuel?
any info would be greatly appreciated.
Are factory O2 sensors needed for the AFR change or will the PCM sort out the required AFR target dependant on what % ethanol content from flex fuel sensor using the new tuned VE table for 98 fuel?
any info would be greatly appreciated.
Staging Lane
Joined: Apr 2017
Posts: 88
Likes: 4
Have a stupid question but here goes. LS1 single turbo, not running any O2 sensors just wide band sensor and AFR gauge. Was thinking going down this flex fuel track but unsure if I'd be able to do this P01 flex fuel setup if I'm not running factory O2 sensors?
Are factory O2 sensors needed for the AFR change or will the PCM sort out the required AFR target dependant on what % ethanol content from flex fuel sensor using the new tuned VE table for 98 fuel?
any info would be greatly appreciated.
Are factory O2 sensors needed for the AFR change or will the PCM sort out the required AFR target dependant on what % ethanol content from flex fuel sensor using the new tuned VE table for 98 fuel?
any info would be greatly appreciated.
Have a stupid question but here goes. LS1 single turbo, not running any O2 sensors just wide band sensor and AFR gauge. Was thinking going down this flex fuel track but unsure if I'd be able to do this P01 flex fuel setup if I'm not running factory O2 sensors?
Are factory O2 sensors needed for the AFR change or will the PCM sort out the required AFR target dependant on what % ethanol content from flex fuel sensor using the new tuned VE table for 98 fuel?
any info would be greatly appreciated.
Are factory O2 sensors needed for the AFR change or will the PCM sort out the required AFR target dependant on what % ethanol content from flex fuel sensor using the new tuned VE table for 98 fuel?
any info would be greatly appreciated.
You just need to make sure that your VE tables are dead on. The flexfuel sensor is what will determine what ratio you need to be at, the rest is calculated by the tables. o2 sensors will simply allow for adjustments during driving.
Slightly OT question, does this make any difference for small changes in the amount of ethanol in the fuel? Like every time I get gas I don't know the exact % ethanol I'm getting. In my tune I just set stoich at 14.36, since I tested some gas a couple of years ago and that was about right at the time, but could change at every fill-up for all I know. How sensitive are the fuel sensors?
Staging Lane
Joined: Apr 2017
Posts: 88
Likes: 4
Slightly OT question, does this make any difference for small changes in the amount of ethanol in the fuel? Like every time I get gas I don't know the exact % ethanol I'm getting. In my tune I just set stoich at 14.36, since I tested some gas a couple of years ago and that was about right at the time, but could change at every fill-up for all I know. How sensitive are the fuel sensors?
P59 Which OS (No Tach) I'm working on a friend's 2001 Camaro and I put a P59 ECU in it so we can run Flex and 3 Bar.
I've had tons of experience in the past with 0411 ECUs and similar setups and E38s, etc...
I have a couple of things I was going to try, but right now I tried a 2004 Tahoe and 2005 Express van file, but the TACH does not work.
I understand the tach on these cars is now operating off of Class 2 Serial instead of a tach wire.
I am going to try segment swapping everything from a 2005 5.3 Avalanche or even just flashing an Avalanche file instead. Or try a 2004 CTS-V file.
I assume that 2004 Tahoe and 2005 Express van do not send RPM over Class 2 and this is why the tach won't work?
I can always put LT1 gauges in and wire in what's needed but before I start doing write Entires 2 more times, I wanted to check if anyone else has ran into a "no tach" situation.
I don't need Auto controls, so I'm assuming CTS-V file would still work as long as its in a P59 with IAC drivers, since the OS appears to control IAC in it. I also downloaded a 2006 Hummer file which I'll try since its been suggested in this thread
Thanks in advance!
I've had tons of experience in the past with 0411 ECUs and similar setups and E38s, etc...
I have a couple of things I was going to try, but right now I tried a 2004 Tahoe and 2005 Express van file, but the TACH does not work.
I understand the tach on these cars is now operating off of Class 2 Serial instead of a tach wire.
I am going to try segment swapping everything from a 2005 5.3 Avalanche or even just flashing an Avalanche file instead. Or try a 2004 CTS-V file.
I assume that 2004 Tahoe and 2005 Express van do not send RPM over Class 2 and this is why the tach won't work?
I can always put LT1 gauges in and wire in what's needed but before I start doing write Entires 2 more times, I wanted to check if anyone else has ran into a "no tach" situation.
I don't need Auto controls, so I'm assuming CTS-V file would still work as long as its in a P59 with IAC drivers, since the OS appears to control IAC in it. I also downloaded a 2006 Hummer file which I'll try since its been suggested in this thread
Thanks in advance!
Bumping this for several reasons. I have a 411 working with flex in the car now. Basically everything works but cruise, has anyone figured that out yet? If not is a p59 a direct drop in for fbody, because ill switch to that if its possible to get cruise and the tach working. Trying to do power tour later this year and would like to get cruise working.
Staging Lane
Joined: Apr 2017
Posts: 88
Likes: 4
Bumping this for several reasons. I have a 411 working with flex in the car now. Basically everything works but cruise, has anyone figured that out yet? If not is a p59 a direct drop in for fbody, because ill switch to that if its possible to get cruise and the tach working. Trying to do power tour later this year and would like to get cruise working.
And tell me what you got. I'll try tomorrow, because I was on P59 since 2018, but with an A4, now i'm M6 since saturday and my Cruise doesn't work too.
Last edited by Guillaume Malaquin; May 2, 2021 at 05:38 PM.
Staging Lane
Joined: Apr 2017
Posts: 88
Likes: 4
Is it a manual trans? If yes, try to put the 33 blue in 35 blue on the PCM it's what normaly use P59. Or 32 Blue if the original P411 work better.
And tell me what you got. I'll try tomorrow, because I was on P59 since 2018, but with an A4, now i'm M6 since saturday and my Cruise doesn't work too.
And tell me what you got. I'll try tomorrow, because I was on P59 since 2018, but with an A4, now i'm M6 since saturday and my Cruise doesn't work too.
Tried Blue 32 like original P411 - > Doesn't Work
I relocated to the Blue 33 like the GTO 2004, I'll see if it works when I came back from work.
EDIT: Don't work on Blue 33 too.
Last edited by Guillaume Malaquin; May 4, 2021 at 12:10 PM.
Old thread but good thread. Just want to say Thanks for the Info! I am overhauling my 2000 GMC Yukon. It's getting a fresh 5.3 with a small cam, headers, converter, and I wanted to run flex fuel. I ordered the flex fuel sensor, harness, and adapter from Racetronix. Flashed a 2002 flex fuel OS, copied my tune settings over. The truck wouldn't start. I had to turn off VATS under system then it fired right up. Maybe this is a given but I spent a couple hours reading and never seen it mentioned. So I am just passing it a long for anybody that might run into the same issue.
TECH Resident
Joined: Oct 2006
Posts: 993
Likes: 173
From: Euless, TX
Old thread but good thread. Just want to say Thanks for the Info! I am overhauling my 2000 GMC Yukon. It's getting a fresh 5.3 with a small cam, headers, converter, and I wanted to run flex fuel. I ordered the flex fuel sensor, harness, and adapter from Racetronix. Flashed a 2002 flex fuel OS, copied my tune settings over. The truck wouldn't start. I had to turn off VATS under system then it fired right up. Maybe this is a given but I spent a couple hours reading and never seen it mentioned. So I am just passing it a long for anybody that might run into the same issue.