Flexfuel sensor location
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Flexfuel sensor location At the point where I'm placing the flexfuel sensor, I like the placement of it attached directly to the return port of the fuel pressure regulator. It'd be the cleanest/shortest length for my wiring but I don't know if being attached like that is going to cause issues or if I should have it a little further down stream. Any opinions on this would he appreciated
I have mine about 2 feet after the fpr and it was fine driving around and tuning. Went to the track the other day and during the pass the reading fluctuated from 70% to about 50% which was throwing off some of my custom tables. I tweaked the frequency the ecu averages the data and will tweak the tables if I need to. I'm guessing there is air or just turbulence in the return line. Not really an issue for me since I knew the % was good so it's staying right where it is.
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I have mine about 2 feet after the fpr and it was fine driving around and tuning. Went to the track the other day and during the pass the reading fluctuated from 70% to about 50% which was throwing off some of my custom tables. I tweaked the frequency the ecu averages the data and will tweak the tables if I need to. I'm guessing there is air or just turbulence in the return line. Not really an issue for me since I knew the % was good so it's staying right where it is.
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Joined: Dec 2004
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From: Florida
It's uncovering the sensor inside since it's not returning enough fuel, that's why you don't put it in the return line after the fuel pressure regulator unless you have a better computer that can latch ethanol content before going WOT. I have found the best place is after the fuel rails before the regulator so it's under constant pressure and is not a restriction feeding the rails. Or get one of those fancy Motion Raceworks flex sensor bypass units and just stick it in the feed line and not worry about it being a restriction.
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From: Louisiana
My feed line goes into regulator, from regulator to drivers fuel rail, and passenger rail goes out to flex fuel sensor, flex fuel goes to return. No issues, holds 58 psi. My fuel rail regulator is mounted to firewall besides brake booster and the flex fuel sensor is hidden behind the intake manifold.
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Teching In
Joined: Dec 2022
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From: SE Wisconsin
My feed line goes into regulator, from regulator to drivers fuel rail, and passenger rail goes out to flex fuel sensor, flex fuel goes to return. No issues, holds 58 psi. My fuel rail regulator is mounted to firewall besides brake booster and the flex fuel sensor is hidden behind the intake manifold.
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From: Louisiana
Teching In
Joined: Dec 2022
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From: SE Wisconsin
The regulator normally goes after the injectors. If it is before the injectors, how would you know what the pressure is at the injectors?
It's uncovering the sensor inside since it's not returning enough fuel, that's why you don't put it in the return line after the fuel pressure regulator unless you have a better computer that can latch ethanol content before going WOT. I have found the best place is after the fuel rails before the regulator so it's under constant pressure and is not a restriction feeding the rails. Or get one of those fancy Motion Raceworks flex sensor bypass units and just stick it in the feed line and not worry about it being a restriction.
I 100% agree with ya. But like I said it's not an issue for me personally because I already know what the percentage is before a pass. What it reads going down track doesn't bother me. If it was a street car where I was relying on it full time yes put it in the feed line, although the only time mine fluctuates is making a hit. I was just answering the op's questions. I also have 1 of the sensor bypass deals but from radium iirc, may not be helping the uncovering situation.
Ideally, I think a Y should be used but this arrangement hasn't had any issues.
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From: Florida
ive been running the inlet from the pump in one side of the regulator and the feed to the stock truck rails from the other side for years and its been fine. i have never really pushed any limits but i dont see how that would be a limfac before the stock tbss rails themselves.
Teching In
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From: SE Wisconsin
ive been running the inlet from the pump in one side of the regulator and the feed to the stock truck rails from the other side for years and its been fine. i have never really pushed any limits but i dont see how that would be a limfac before the stock tbss rails themselves.
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From: Louisiana
I actually said it backwards after I looked at it, feed line ito flex fuel sensor, from there to passenger rear rail, rails connected in front, and drivers rear goes out into regulator then, and the return is on the bottom port of regulator and the other fuel port on the regulator goes into my nitrous fuel solenoid
ive been running the inlet from the pump in one side of the regulator and the feed to the stock truck rails from the other side for years and its been fine. i have never really pushed any limits but i dont see how that would be a limfac before the stock tbss rails themselves.
I ran the factory return less fuel system on my 02 Camaro at 700whp for years, literally twin 255's with one on a Hobbs switch, everything else was stock lol.
I actually said it backwards after I looked at it, feed line ito flex fuel sensor, from there to passenger rear rail, rails connected in front, and drivers rear goes out into regulator then, and the return is on the bottom port of regulator and the other fuel port on the regulator goes into my nitrous fuel solenoid
I think with fuels that require significantly more volume like E85 and Methanol, then equal distribution to each rail becomes more of an issue.
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From: Louisiana
MM told me that factory return less style systems start having delivery consistency issues above the 700-800whp mark.
I ran the factory return less fuel system on my 02 Camaro at 700whp for years, literally twin 255's with one on a Hobbs switch, everything else was stock lol.
Identical to mine basically, the only downside I've been told is that when you reach the limits of the pump or pumps, the rail that gets fuel second would see reduced pressure to those injectors, but I think that's a very extreme case and I've never heard of it actually happening to anyone.
I think with fuels that require significantly more volume like E85 and Methanol, then equal distribution to each rail becomes more of an issue.
I ran the factory return less fuel system on my 02 Camaro at 700whp for years, literally twin 255's with one on a Hobbs switch, everything else was stock lol.
Identical to mine basically, the only downside I've been told is that when you reach the limits of the pump or pumps, the rail that gets fuel second would see reduced pressure to those injectors, but I think that's a very extreme case and I've never heard of it actually happening to anyone.
I think with fuels that require significantly more volume like E85 and Methanol, then equal distribution to each rail becomes more of an issue.
