Flex Fuel sensor readings drop when in boost - Page 5 - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

eLeSthree · 06-14-2020, 05:39 PM

It looks like you're not alone. I've been noticing these dips in FF % lately. It only seems to happen when the car is on a good hit, with traction, front end lifting a bit. Not really boost related, or FP related. I have triple 450s, a -10 feed Y'd into two -8 into rails, FPR after rails, and -8 return with FF sensor about 2.5' away from regulator.

I guess it's time to plumb it into the feed line with a couple Y's.

dreksnot · 06-14-2020, 05:47 PM

Sometimes it best not to know. Then, some dude brings it up and crashes the party. But, I guess I would still like to know what's up. Both you and I have plenty of fuel flowing through the FF sensor with our triples. We're missing something....

I just wired my triples to have 2 pumps run all the time with the 3rd on Hobbs. Not that it will help with the FF% issue, but it should help with other transient issues I've been having.

Greenhornet2 · 06-14-2020, 06:47 PM

Still following this thread. Really curious to see if changing it to the feed line helps. My gut tells me it will.

eLeSthree · 06-14-2020, 06:55 PM

You’re that guy!!

DSX swears it causes problems being in the return. Dave insists it must be in the feed seeing pressure.

stevieturbo · 06-15-2020, 03:13 AM

Power house racing do neat bypass units. Negates any need for lots of bullshit fittings and tees or y's

Although I think the larger size is -8. At least that's what I bought and have in my return.

eLeSthree · 06-15-2020, 05:37 AM

Quote:

Originally Posted by stevieturbo

Power house racing do neat bypass units. Negates any need for lots of bullshit fittings and tees or y's

Although I think the larger size is -8. At least that's what I bought and have in my return.

Thanks Steve, they actually do have a -10!

https://www.powerhouseracing.com/pro...x-fuel-adapter

Not a bad price either.

eLeSthree · 06-15-2020, 05:54 AM

There is another option... a free option. You can edit the column/row axis of the alcohol composition table. For example, if you know your E is 75% at idle, its gonna be 75% at WOT. Its just that the sensor isnt getting a good flow/reading. So change the column/row axis from 50% to say %60 or whatever you reading usually dips down to. That way you get all of your timing, and if you ever pump in some crap 93, you're timing will be pulled as intended from the lower % areas of the tune.

In my case, I NEVER run anything but good 75% E. If you daily your car, and sometimes put 93 in it, you could actually be at %60 and see full timing, which you wouldnt want. So depending on your use, it could be risky.

Rem0v3r · 06-23-2020, 06:41 PM

The sensor works by detecting the electrical resistance of the fuel.. high pressure might adjust this.. might not.

You can adjust the tune so it doesn't change the composition timing right away.. just dont floor it when leaving the gas station

Badbubba · 06-25-2020, 03:42 PM

I see no reason why pressure or flow rate at the ff sensor would change the value of ethanol content. As long as the sensor is "full". Besides, pressure is established by resistance to flow. With the return line being open ended into the tank, there's not going to a lot of pressure in the line. OP did state the sensor was in a high location. Maybe put it in a low location, basically like a P-trap drain under your sink. If the sensor is close to the fuel pressure regulator, could some of the fuel be changing state after the fp regulator due to the differential pressure?

stevieturbo · 06-25-2020, 05:01 PM

A very small restriction after the sensor may be the answer, if you cannot set the ecu to only take readings say at low rpm, then lock the reading thereafter.

Lets face it...the fuel isnt going to suddenly change at any point

Rem0v3r · 06-25-2020, 07:44 PM

Nah, you guys are making this too difficult...
Go to engine--fuel--flexfuel and adjust the learning trigger value to a higher number (maxes out at 4 liters).. I hope non of you are flooring it leaving the gas station and I doubt your drinking more than 4 liters of gas on a single pull..... problem solved.

eLeSthree · 06-25-2020, 09:11 PM

Quote:

Originally Posted by Rem0v3r

Nah, you guys are making this too difficult...
Go to engine--fuel--flexfuel and adjust the learning trigger value to a higher number (maxes out at 4 liters).. I hope non of you are flooring it leaving the gas station and I doubt your drinking more than 4 liters of gas on a single pull..... problem solved.

Ill try this out tomorrow morning, thanks.

I'm not going to set it to 4 liters, but I did increase it from 0.01 liters to 0.05. We'll see if that delays the comp change enough.

dreksnot · 06-25-2020, 09:30 PM

Quote:

Originally Posted by Rem0v3r

Nah, you guys are making this too difficult...
Go to engine--fuel--flexfuel and adjust the learning trigger value to a higher number (maxes out at 4 liters).. I hope non of you are flooring it leaving the gas station and I doubt your drinking more than 4 liters of gas on a single pull..... problem solved.

Currently set to 0.09L, which is 3 fluid ounces. I'll double it and see what that does (after I get my wastegate diaphragms replaced in the next couple of days).

Rem0v3r · 06-26-2020, 06:18 PM

Quote:

Originally Posted by dreksnot

Currently set to 0.09L, which is 3 fluid ounces. I'll double it and see what that does (after I get my wastegate diaphragms replaced in the next couple of days).

Awesome.. you guys can always log the pull then guesstimate what number to use based on the change time... I wouldn't do 4 liters either

06-14-2020, 05:39 PM	#57
eLeSthree Drives: 2011 Camaro SS 6sp Join Date: Nov 2016 Location: Drivers Seat Posts: 1,904	It looks like you're not alone. I've been noticing these dips in FF % lately. It only seems to happen when the car is on a good hit, with traction, front end lifting a bit. Not really boost related, or FP related. I have triple 450s, a -10 feed Y'd into two -8 into rails, FPR after rails, and -8 return with FF sensor about 2.5' away from regulator. I guess it's time to plumb it into the feed line with a couple Y's. Attached Images __________________ 2011 Camaro SS---SOLD TMS Dart 427 FED M311s, ESS Tuning G4 Blower, DSX Triple FP Assembly, DSX FF, FIC1300, Mcleod RXT 1200HD, Edlebrock Pro Flo XT 1158whp 1017wtq. 2010 CTS-V A6 - "Stock" SOLD 630whp 658wtq 2024 F-150 RCSB 5.0 4x4 waiting for tunes...

06-14-2020, 05:47 PM	#58
dreksnot Served USN - Atomic Chimp Drives: 13 Camaro LSX434 TT M6, 21 ZLE A10 Join Date: Jul 2012 Location: Fort Collins, CO Posts: 1,603 View My Garage	Sometimes it best not to know. Then, some dude brings it up and crashes the party. But, I guess I would still like to know what's up. Both you and I have plenty of fuel flowing through the FF sensor with our triples. We're missing something.... I just wired my triples to have 2 pumps run all the time with the 3rd on Hobbs. Not that it will help with the FF% issue, but it should help with other transient issues I've been having. __________________ In excess of 1,000WHP LSX434 \| AGP 65/65 TT \| BTR Equalizer Intake \| Trickflow 245cc cathedral \| BTR custom cam \| Cortex EBC \| n2mb WOT \| ID-1700x \| Brisk GR12S \| RPM Lv 7 TR6060 \| AGP's Triple 525LPH Fore Fuel \| Monster LT1-S Triple \| 4.11 DSS Proform 9", CF driveshaft, 1400hp axles \| Hurst Line Lock \| MGW Retro Short Throw w/old skool Hurst T-handle \| ADM solid subframe mounts \| Prothane Motor Mounts \| Revshift Poly Trans insert \| Moreno camber/caster plates

06-14-2020, 06:47 PM	#59
Greenhornet2 Drives: 2011 Camaro 2SS LS3 Whipple Join Date: May 2019 Location: Connecticut Posts: 1,925	Still following this thread. Really curious to see if changing it to the feed line helps. My gut tells me it will. __________________ Whipple 2.9 CAI ID1050x injectors ZL1 Pump JRE FPCM JMS Voltage booster JRE Rough Idle blower cam BTR .660 springs CHE trunnion kit 1 7/8 Speed Engineering Borla Atak JRE scoop 1.5" lowering springs BMR trailing arms and toe links Cradle inserts 704WHP 603WTQ 93 octane

06-14-2020, 06:55 PM	#60
eLeSthree Drives: 2011 Camaro SS 6sp Join Date: Nov 2016 Location: Drivers Seat Posts: 1,904	You’re that guy!! DSX swears it causes problems being in the return. Dave insists it must be in the feed seeing pressure. __________________ 2011 Camaro SS---SOLD TMS Dart 427 FED M311s, ESS Tuning G4 Blower, DSX Triple FP Assembly, DSX FF, FIC1300, Mcleod RXT 1200HD, Edlebrock Pro Flo XT 1158whp 1017wtq. 2010 CTS-V A6 - "Stock" SOLD 630whp 658wtq 2024 F-150 RCSB 5.0 4x4 waiting for tunes...

06-15-2020, 05:54 AM	#63
eLeSthree Drives: 2011 Camaro SS 6sp Join Date: Nov 2016 Location: Drivers Seat Posts: 1,904	There is another option... a free option. You can edit the column/row axis of the alcohol composition table. For example, if you know your E is 75% at idle, its gonna be 75% at WOT. Its just that the sensor isnt getting a good flow/reading. So change the column/row axis from 50% to say %60 or whatever you reading usually dips down to. That way you get all of your timing, and if you ever pump in some crap 93, you're timing will be pulled as intended from the lower % areas of the tune. In my case, I NEVER run anything but good 75% E. If you daily your car, and sometimes put 93 in it, you could actually be at %60 and see full timing, which you wouldnt want. So depending on your use, it could be risky. Attached Images __________________ 2011 Camaro SS---SOLD TMS Dart 427 FED M311s, ESS Tuning G4 Blower, DSX Triple FP Assembly, DSX FF, FIC1300, Mcleod RXT 1200HD, Edlebrock Pro Flo XT 1158whp 1017wtq. 2010 CTS-V A6 - "Stock" SOLD 630whp 658wtq 2024 F-150 RCSB 5.0 4x4 waiting for tunes...

06-15-2020, 03:13 AM	#61
stevieturbo Drives: it changes Join Date: Nov 2010 Location: Norn Iron Posts: 1,126	Power house racing do neat bypass units. Negates any need for lots of bullshit fittings and tees or y's Although I think the larger size is -8. At least that's what I bought and have in my return.

06-23-2020, 06:41 PM	#64
Rem0v3r Drives: 2013 ss2 vert l99 Join Date: Apr 2017 Location: South florida Posts: 150	The sensor works by detecting the electrical resistance of the fuel.. high pressure might adjust this.. might not. You can adjust the tune so it doesn't change the composition timing right away.. just dont floor it when leaving the gas station

06-25-2020, 03:42 PM	#65
Badbubba GrINned & JUICEd Drives: 15STI, 10Expy, 10 2SS/RS M6, 47KB1 Join Date: Nov 2009 Location: Pittsburgh, PA Posts: 1,247	I see no reason why pressure or flow rate at the ff sensor would change the value of ethanol content. As long as the sensor is "full". Besides, pressure is established by resistance to flow. With the return line being open ended into the tank, there's not going to a lot of pressure in the line. OP did state the sensor was in a high location. Maybe put it in a low location, basically like a P-trap drain under your sink. If the sensor is close to the fuel pressure regulator, could some of the fuel be changing state after the fp regulator due to the differential pressure? __________________ GPI SS3 Cam & stuff,N.O. Plate(dedicated fuel tank,progressive,fuel hose upgrade,remote opener,heater,console switches),LNC2000,CTAP,ARH 1 7/8" LTs/gutted cats/X pipe/mufflers,Jet Hot coated LTs,GPI HPT Tune,CAI, Scoop,Rx Catch Can,Gates heater hose relocation, Remote clutch & auto brake res,Metco loop,Momentum Tunnel Brace,TSW Nurb 18",555 & 05,Pfadt trailing arms & toe rods,Autometer WB,Fesler Pillar Pod,LED strips (int),Lloyds floor & trunk mats,LED DRL/front turn & license plate,DRL harness,VLEDs tail lights,Plasticoat Bowties. Ord: Oct 5, 2009 Rec: Nov 19, 2009 13.17@112.6 stock

06-25-2020, 05:01 PM	#66
stevieturbo Drives: it changes Join Date: Nov 2010 Location: Norn Iron Posts: 1,126	A very small restriction after the sensor may be the answer, if you cannot set the ecu to only take readings say at low rpm, then lock the reading thereafter. Lets face it...the fuel isnt going to suddenly change at any point

06-25-2020, 07:44 PM	#67
Rem0v3r Drives: 2013 ss2 vert l99 Join Date: Apr 2017 Location: South florida Posts: 150	Nah, you guys are making this too difficult... Go to engine--fuel--flexfuel and adjust the learning trigger value to a higher number (maxes out at 4 liters).. I hope non of you are flooring it leaving the gas station and I doubt your drinking more than 4 liters of gas on a single pull..... problem solved.