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Help.. Choosing wire size for flex fuel sensor

EFI Wiring Fundamentals

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Discussion and questions related to the course Motorsport Wiring Fundamentals

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Hey everyone.

So I am wiring in a flex fuel sensor and I have decided to make this my first of two wiring projects for the car I am working on. Small steps. I purchased what should be the proper size tools, pins, plug, etc.. (this proved to be alot more complicated than I imagined to properly source each individual part).

I am not sure what size and type of wire to use. Starting with size.

I have the wiring diagrams for amps vs length of wire but I am not sure the amount of amps this sensor requires and I cannot seem to find that info anywhere. All I have found is it uses 9 - 18v. So how does one go about finding the amps of a sensor to properly choose the correct size wire?

As far as the type of wire I am just looking for recommendations. The websites I was looking at have cross link, primary, and hookup wire.

I have run the Continental Flex sensors using 22g Tefzel in a vehicle, with the cable run to the sensor from the ECU around 4m. I have used 26g Tefzel for them on the bench without issues as well.

Most Temp and Pressure sensors have very low current draws (otherwise they would overload the 5V rails on ECU's) so can be used with quite small wire diameters. As an example, the common wire size for sensors used in Supercars is 24g, One of the guys that I work with used to do wiring for Williams F1, and most of their looms used 28g and 30g for sensors.

I appreciate the help. I have come to find one of the hardest parts of getting into wiring is getting the proper information to make educated decisions. I am the type of person that wants to know why something is done a certain way not just go with the crowd. I guess that is how I ended up on this forum and buy alot of education type courses. HPA - You guys need more in dept wiring courses. I am ready. =)

When you say low current draw, what are we talking?

The run from my sensor to the ecu is probably about 5 feet at most. You would run 22g for all 3 wires?

Low Current is typically less than 1A, most sensors are a lot lower than that.

I have 22g wire for my sensor, and that is mounted about 4m from my ECU.

As I am still working on getting a grasp of the basics.

Now before I get started I understand that most connectors are designed for standard automotive wire and you are limited to how small you can go awg because of the pins used by OEM connectors. I am simply trying to get the idea for what would be the best wire if I could use it.

Looking at the injector example Ryan gives in the course.

I have a set of I'd 1700's say they are 9ohms.

Ohms law



1.5x20% =1.8amps

I don't have a foot to resistance chart for tefzel wire. Looking Ryan's tefzel wire specs chart. I could be 22awg or even smaller

I am running this wire about 4 feet so I am not sure how that plays in and when you look at other charts most represent wire at 20c not 100c.

Most Race looms that I have seen, use 22awg for the injectors, some even have 24awg. The issue with using these thinners wires is usually related to who wrenches the car, some mechanics are pretty brutal with looms, and this can cause more issues in a smaller gauge loom than a larger on.

What about coils BlackRex? 22 for the triggers and 20awg for the power and ground?

Depends on the coils, but the LS "Truck Engine" coils that I use are all wired with 22AWG wire, and I don't have an issue with ignition.

apologies i was referring to denso / toyota 1zz 1nz coils.

22 can be used as the duty cycle is low on coils, especially sequential fired, but if you are concerned about it, then 20 or 18 is not going to cause any issues if you use it.

Hi all,

Sorry for posting on an old thread,

does anyone have a link or image of a Tefzel Resistance chart?

Thank you

Hello Joshua,

Attached is Motec's specifications for M22759/16 and here is a link for M22759/32... although they are essentially the same electrically.

Attached Files

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