Flex Fuel Sensor with DIYPNP - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


MEGAsquirt A place to collectively sort out this megasquirt gizmo

Reply
 
 
 
LinkBack Thread Tools
Old 12-02-2014, 08:25 AM   #1
Newb
Thread Starter
 
Join Date: Jun 2013
Location: San Diego, CA
Posts: 26
Total Cats: -15
Default Flex Fuel Sensor with DIYPNP

Got a GM flex fuel sensor for my 96, have power and ground wires ran. I've read that the output wire from the sensor needs a resistor? If so, how do I go about doing so inside the ECU?
Thanks in advance!
96miata is offline   Reply With Quote
Old 12-02-2014, 08:59 AM   #2
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,835
Total Cats: 1,786
Default

can ms2 even do flex fuel?
Braineack is online now   Reply With Quote
Old 12-02-2014, 10:07 AM   #3
Supporting Vendor
iTrader: (10)
 
Reverant's Avatar
 
Join Date: Jun 2006
Location: Athens, Greece
Posts: 5,440
Total Cats: 198
Default

Yes it can, but it's very rough around the edges.
Reverant is offline   Reply With Quote
Old 12-02-2014, 12:35 PM   #4
Supporting Vendor
 
Matt Cramer's Avatar
 
Join Date: Sep 2006
Posts: 2,264
Total Cats: 51
Default

Notes on flex fuel input for a DIYPNP are here:

https://www.diyautotune.com/diypnp/d...lex_Fuel_Input
Matt Cramer is offline   Reply With Quote
Old 12-02-2014, 03:38 PM   #5
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,835
Total Cats: 1,786
Default

i guess that makes sense since there's an input called "FLEX" :P
Braineack is online now   Reply With Quote
Old 10-08-2017, 07:47 PM   #6
Junior Member
 
Join Date: Dec 2008
Location: Ft. Lauderdale, FL
Posts: 273
Total Cats: 7
Default

Forgive the thread necromancy, but I did not want to start a new thread and searching brought this post up.

Has anyone actually run a flex fuel sensor with a DIYPNP? I know a ton of people do it quite successfully with the MS3x, but I already have a DIYPNP running very well in my '99 VVT swap daily (Made 148whp in 98 degree dyno conditions). I don't want to spend any additional money on another Megasquirt, especially if the DIYPNP can handle E85 input and actually function.
MX5RACER is offline   Reply With Quote
Old 10-09-2017, 12:40 PM   #7
Elite Member
iTrader: (17)
 
Join Date: Aug 2007
Location: Fort Myers, FL
Posts: 2,790
Total Cats: 128
Default

I tried to check how MS2 handles flex fuel, but can't get any good info (a lot of blocked sites at work). I seem to remember it being set up so it adds a fixed amount of timing and % of fuel per content of alcohol. Either that or you have dual tables, but it will only allow you to straight line blend between them.

If you can just add fixed levels of timing and fuel, it may not be as precise as dual tables but I would still feel pretty confident doing it, and you should definitely gain power doing it. If you have dual tables and it blends between them, that's exactly how I'm running my MS3X. The fancy blend curve stuff looks nice and all, and I'm sure it'd make a little more power with mixed fuels if you took the time to dial it in perfectly, but straight line blending seems to be safe, easy, and has worked well for me when I've gotten lower ethanol E85.
pdexta is offline   Reply With Quote
Old 10-09-2017, 01:43 PM   #8
Supporting Vendor
iTrader: (31)
 
Savington's Avatar
 
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 14,357
Total Cats: 1,322
Default

Fixed levels will run pretty poorly on E85. MS3 starts with a fixed multiplier but to actually get the car to run smoothly you need a lot of VE3 table tweaks. The fuel requirement differences vary heavily based on coolant temps and load.
Savington is offline   Reply With Quote
Old 10-09-2017, 01:48 PM   #9
Senior Member
iTrader: (1)
 
Join Date: Dec 2010
Location: Farmington Hills, MI
Posts: 871
Total Cats: 93
Default

I would think Flex Fuel would be beneficial with a DIYPNP for small changes in ethanol content. Say you tune for E78 and you fill up with E82, a fixed multiplier is better than nothing. But I wouldn't tune for gasoline and use a fixed multiplier to run E85.
acedeuce802 is offline   Reply With Quote
Old 10-09-2017, 02:36 PM   #10
Elite Member
iTrader: (17)
 
Join Date: Aug 2007
Location: Fort Myers, FL
Posts: 2,790
Total Cats: 128
Default

I know Hondata recently added flex sensor support via fixed multipliers and all the honda bois around here are jumping on that. For me personally, since I set up flexfuel I haven't filled with anything but E85. I just don't have any reason to swap fuels. At the very least you can dial in a tune for your primary fuel, and you at least know you've got decent secondary fuel map that will get you around.

If you're really going to be switching all the time it'd be easy enough to set up 2 tunes. Have a 93 tune that uses the fixed values to get close enough on E85. Then a E85 tune that uses fixed values to get close enough on 93. Before I had a flex sensor I just tuned for E85, and kept a 93 tune on MSDroid for the off chance I got stranded somewhere.
pdexta is offline   Reply With Quote
Old 10-09-2017, 04:05 PM   #11
Junior Member
 
Join Date: Aug 2009
Posts: 54
Total Cats: 0
Default

I switch all the time

I run separate maps. for those 1 tanks in-beteween when there is like 15-20% ethanol still in the tank or vice versa andI adjust the injector flow I then also give the EGO correctionb more authority.

It sounds like the E85 sensor is not worth the effeort on MS2 PnP ? I'm on the verge of a 1.8 conversion & was thinking of installing it.

My car seems to really like the 20% ethanol....on a 93 tune.
StanTheMan is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Project Gemini - Turbo Civic on the Cheap Full_Tilt_Boogie Build Threads 57 07-19-2017 05:11 PM
My solution for Oiltemp and Oilpressure input into Megasuirt (MS3) Zaphod MEGAsquirt 41 01-24-2016 01:25 PM
Time to start learning and play with tuning The Gleas MEGAsquirt 3 10-01-2015 10:30 AM
Walbro 255lph Fuel Pump $50 lsc224 Miata parts for sale/trade 2 10-01-2015 10:17 AM


Tags
diy pnp, e85, flexfuel, mega squirt

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 10:26 AM.