ECU Sensor Resistor

17.1.4.D.1.a.6. Fuel injected cars may alter or replace the engine
management computer, or ECU, provided that all
modifications are done within the original OEM ECU
housing. Only the stock (unmodified) OEM ECU
connection to the wiring harness may be used. The
allowance to modify the ECU in no way permits the
addition of wiring, sensors, or piggybacked computers
outside of the OEM ECU housing. The stock (unmodified)
wiring harness must be used. The installation of a
resistor is allowed between the sensor and the OEM
wiring harness. Adjustable fuel pressure regulators are
permitted.

I assume the resistor can be adjustable. Can the adjustment be within reach of the driver? I don't see why not, but this would require some wires running into the passenger compartment.

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I assume the resistor can be adjustable. Can the adjustment be within reach of the driver? I don't see why not, but this would require some wires running into the passenger compartment. [/b]

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I'm sure there are those that would agree with your assumption that the resistor can be adjustable, but I do not. IMO, an "adjustable resistor" is certainly not the same as a "resistor"... I'm no EE, but I believe an adjustable (variable) resistor is called a rheostat. If they had intended the allowed use of a rheostat, don't you think they would have used that word? Or at the very least, wouldn't "resistor" be preceeded by the word "variable" or "adjustable", as in the last sentence of the very paragraph you quote, where they specify "Adjustable fuel pressure regulator...."?

Marty, this doesn't prove that it is legal today but in the past I and a number of other RX-7 drivers had a variable resistor in the wire between the water thermosensor and the ECU. It required no more than a couple of feet of wire inside the car because it was spliced into the harness at the ECU. The present wording, however, does tend to indicate that the resistor should be in the wire from the sensor to the main part of the harness.

I think a literal reading of the rule prevents splicing a resistor into the original harness. Seems to me the only way to implement it is to add an adapter cable with resistor that plugs into the stock harness on one end and plugs into the sensor on the other end.

Yet another reason why IT rules are best termed rediculous.

This is the kind of "discussion" that continually makes me remember that for me this racing is strictly a "hobby" more like entertainment actually. Doesn't mean I'm not competitive and don't care if I don't do well it's just perspective.

However, at the end of the day if I don't "place" NAPA/General Mills/Viagra won't pull my sponsorship since I'm my own "sponsor". I realize this perspective is probably a minority view but sometimes it seems to me we're getting way too serious about not much.

The fact that the rules make it "legal" to spend thousands of $$$ putting an M4 MoTec into the stock ECU box but exclude other far less expensive "alternative modifications" seems to me counter productive.

Further, the legality of a particular interpretation of the rules is very much determined by who does impound and what region is sponsoring the race I attend.

The range of interpretation for the two schools of thought, "if it doesn't say you can you can't vs if it doesn't say you can't maybe you can" is limitless.

Fact is I'm guessing we ALL push the limits of rulesmanship until we start winning races and someone in "authority" says no that's illegal.

tbtapper
ITS 19

A variable rate resistor is commonly referred to as a potentiometer. A rheostat is a type of potentiometer.

A strict interpretation would be that the resistor is not allowed to be adjustable as previously posted.

I'd also be interested in an interpretation of the word between. Does that mean you can create a new harness that runs wherever you want and then connects to the stock harness? Or does it mean only so much as need to integrate the resistor?

So if the dash isn't between the harness and sensor you couldn't put the resistor there.

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A variable rate resistor is commonly referred to as a potentiometer. A rheostat is a type of potentiometer.

A strict interpretation would be that the resistor is not allowed to be adjustable as previously posted.[/b]

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I think we'll have to agree to disagree on that one. A potentiometer is a resistor (as you described). There is no qualification beyond "resistor", so any kind of resistor (including potentiometer) is allowed.

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I'd also be interested in an interpretation of the word between. Does that mean you can create a new harness that runs wherever you want and then connects to the stock harness? Or does it mean only so much as need to integrate the resistor?

So if the dash isn't between the harness and sensor you couldn't put the resistor there.[/b]

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This is the part that I'm pretty uncertain about.

"You reap what you sow..."

BWAH-HAHA-HAH-HAH-HAH-HAH!!!

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I think we'll have to agree to disagree on that one.
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I can't agree to that. :D

This might all be a waste of your time. What are you trying to accomplish by the addition of this driver adjustable resistor?

What's the GCR glossary definition of "between?"

The question here seems to be, "If a resistor can be changed, can it be controlled in real time?" If that's OK, I can control it by some other means besides turning a knob, right?

My new wideband O2 controller is a gauge, BTW.

Whee!

K

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I can't agree to that. :D [/b]

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Then you're fired. :lol:

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This might all be a waste of your time. What are you trying to accomplish by the addition of this driver adjustable resistor?[/b]

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I'm getting a lot of heat soak on the air temp sensor - close to 100* above ambient. I'm pretty sure the intake air isn't really that hot. Screws up the mixture - leans it out. So I'm considering my options to compensate for the bad sensor info.

I would try insulating the sensor and/or sensor area before you start playing with the electrical system.

And you clearly fired me for discriminatory reasons, you'll be hearing from my lawyer! :lol:

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I would try insulating the sensor and/or sensor area before you start playing with the electrical system.[/b]

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Yeah, I'm also working that angle.

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And you clearly fired me for discriminatory reasons, you'll be hearing from my lawyer! :lol:
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I'm a very discriminating guy. :cavallo: