Been thinking about the "Hot Wire Mod". I don;t know if it is a big thing or not but I believe the Hot Wire Mod works because the truck is in the open loop configuration which fattens the injector pulse. This I assume hurts fuel mileage. What I was thinking is to parallel the hot wire resistor with a straight wire and a switch on the dash. Close the switch and the fuel management goes to close loop configuration. Open the switch and it goes back to the resistor and open loop. I see this as sort of a performance mode that some cars offered years ago.
Just thinking out loud. Give me some input....

 

i thought that everytime you connect or disconnect the "power wire" you have to reset the pcm? if so than the switch wont do anything. if not than it seems like a good idea.

 

Yeah, from what I get from reading you have to reset your pcm everytime you connect/disconnect the wire like jk said. Maybe wrong tho.

 

Just put in a 180* thermostat, does the same thing. And yes, it will result in a little richer A/F, so fuel economy will suffer, slightly...

 

Well yes but you can also tune that out to run a little leaner too, that is if your tuner will allow you to do that. Or throw some headers on it and it'll lean things out a bit too.

 

I am going to say no, the PCM doesn't need to be reset each time. Here's my reasoning, The IAT being a themistor with a range of resistance determined by inlet air temperature and the resistor (hot wire) being within that specific range (20 degree cooler) it would be the same as the IAT reading cooler air when the switch is open (reading the Hot wire). Close the switch and it reads the straight wire and IAT only. I don't have my truck with me but should be simple enough to test. Give me your thoughts...

 

Well mine ran a CEL until I reset it....so I dunno

But technically, the sensor is for determining outside air temp. The temp changes 20 degrees in a day, so it adjusts according to tha
a different current running through the sensor might be the problem

 

Closed loop operation does run too rich at first but then the learning routine tunes it out so you're back to mostly stock mixture at cruise.

At full throttle, no correction is applied and that's where the extra fuel & timing come into play.

 

Yep, closed loop uses o2 sensor inputs and adjusts accordingly. Open loop ignores the o2 sensor inputs.