Flex fuel sensor install location opinion

[leirch]

So I'm doing a frame off restore and conversion from Alky to E85 and all kinds of other things to my car in the process. I added the Flex fuel sensor above the rear axle and added the wiring for it into the tail light wiring harness to boot(along with the fuel pump hot wire kit) so its completely ninja stealth hidden. Should make for a super clean look.

Do any of you have experience installing the sensor in a similar location? Car is going to be coming back from paint finally so I hope to start assembling it in the next month.

 

[Boost231]

Have mine in the same location

 

[dank GN]

Mine is plumed into the return line and I extended the MAF cable . I put it in the frame rail under the drivers door

 

[ArthurJGuy]

It should be on the return line as close as possible to the fuel rail. Above the axle is WAY to far back.

It should also have a Y fitting before and after, so that it does not hinder flow as they are not the most high flow devices in the world.

 

[Boost231]

It should be on the return line as close as possible to the fuel rail. Above the axle is WAY to far back.

It should also have a Y fitting before and after, so that it does not hinder flow as they are not the most high flow devices in the world.

Why does it need to be as close to the fuel rail as possible? My sensor updates fast enough and the 85 is consistant and not rapidly changing so i see no need. Even when i mix in the e98 to bump of the E contant it takes a while to mix but once it does the fuel energy constant stays the same.

Also it doesn't need a Y fitting in most cars as this sensor flows more then the old GM style sensor. With the old GM sensor we used a Y and with the new sensor we no longer need to. Now if you run a massive pump like i do in my other car then yes even with this sensor it will need a Y depending on the fuel used.

 

[ArthurJGuy]

The most accurate signal is what's coming out of the fuel rail. Placing it at the rear of the car will not give you the same signal as if you place it sensor up front.

I assume anyone that needs E85 has a reason for it, and has a fuel system suitable, so the second half of your statement then applies.

 

[Boost231]

The most accurate signal is what's coming out of the fuel rail. Placing it at the rear of the car will not give you the same signal as if you place it sensor up front.

I assume anyone that needs E85 has a reason for it, and has a fuel system suitable, so the second half of your statement then applies.

It wont, you have data on this? What makes you think the E85 contant changes from the time it leaves the rail to the time it goes back into the tank?

.

 

[ArthurJGuy]

It wont, you have data on this? What makes you think the E85 contant changes from the time it leaves the rail to the time it goes back into the tank?
.

Yes I do, unfortunately I do not have HPTuners anymore or I'd post it.

 

[Boost231]

Would love to see the data if you can post it or how much you think it is and your theory of why it is.

Because imop your not going to lose any and it wouldn't make since to lose any. If e85 is in the tank that's what's coming out of the rail that's the same as what's in the tank.

Unless your talking about having e85 in the tank and going to the gas station and pumping in 91 octane then yes the fuel coming out of the rail will be different as it mixes but once mixed it will stay the same till the next full up.

 

[mtocrs1]

I have mine in the same location above the rear axle. Mine is also plumbed into the feed line. I don't think it will be a restriction but we shall see.

 

[Boost231]

If it's the new style sensor you'll be good. However I would put it in the return line.

 

[turbo89]

The most accurate signal is what's coming out of the fuel rail. Placing it at the rear of the car will not give you the same signal as if you place it sensor up front.

I assume anyone that needs E85 has a reason for it, and has a fuel system suitable, so the second half of your statement then applies.

AGREED !!!!

 

[mtocrs1]

If it's the new style sensor you'll be good. However I would put it in the return line.

Yeah it's the new style.

 

[Wes]

I think putting it that far back would only affect the temp reading that the sensor provides. I don't see how it would affect the ethanol content % output.

 

[evil666]

Have mine in the same location

 

[evil666]

Here's mine.