So there's been people saying that the resistor in a box mod will eventually bring up a fault code and the CEL light due to "a constant fuel temperature value"

But is this the case? Surely the temperature that would usually be sent to the ECU is simply adapted by the resistor by a set amount?

Such as;

Normal reading 10k ohms - altered - 15k ohms

And so on.

Personally I don't think this would bring up a CEL as the value would constantly be changing

The ECU takes readings from multiple inputs, it knows roughly what to expect based on other sensors. When something untoward happens, such as the wrong readings from the MAF then the CEL light comes on, since it is receiving an unexpected reading based on the other sensors in the engine.

The "tuning" box bypassed the fuel temp sensor completely so it gives a fixed signal and hence fault light. Been there done that. To be fair it's a good band per buck. Better spent here than a pd160 intake or exhaust mods.

If it was inline with the original sensor then it wouldn't through a fault.

Ah I see, I thought it was inline, it must throw the reading off by some way then, otherwise in some cases you could loose performace.

Cheers Guys

They force the engine to inject extra fuel, however that has bad side effects including loads of black smoke. Think of it like the old days, driving around with the choke out all the time. Eventually everything including the Turbo will clog up with the excess soot, leading to an expensive repair.

I had two tuning boxes on two different cars...not once did it throw up a fault.....all the ones I have known to throw up faults have been "turned up to 11" ...mine set about halfway never gave any trouble

They force the engine to inject extra fuel, however that has bad side effects including loads of black smoke. Think of it like the old days, driving around with the choke out all the time. Eventually everything including the Turbo will clog up with the excess soot, leading to an expensive repair.

Being just 20, I dont know the old days

I had two tuning boxes on two different cars...not once did it throw up a fault.....all the ones I have known to throw up faults have been "turned up to 11" ...mine set about halfway never gave any trouble

You probably had the ones that plug into the injector section of the loom. Mark was talking amout the ones that bypass the fuel sensor.

Being just 20, I dont know the old days

You'd have loved a choke. Instant powahhh lol

You probably had the ones that plug into the injector section of the loom. Mark was talking amout the ones that bypass the fuel sensor.

First one I had was just a resistor in a box...and again ...no problems....all made by Dragon tuning

I had a resistor mod too that bypassed the fuel sensor. Early car never had a fault but my 2004 vrs did after a while due to the ecu seeing the same fuel temp all the time.