Intake Air Temp resistor experiment.

[usedgeo]

Originally Posted by usedgeo

This mileage is just too darn good. It cannot be true. Here is an unpleasant hypothesis.

What is the chance that the ScangaugeII incorporates the IAT temperature into its fuel use calculation?

Ernie

Well I put on a few extra miles and fueled up. 45.5 mpg. The faux IAT temp of 233 F had virtually no effect. It felt wonderful watching that scanguage for the first couple gallons and then I began to suspect the result I achieved. I could make several analgies to things that make one feel good or warm but produce no useful or functional effect but I will leave them off.

I wrote tech support at Scanguage. They wanted to know what I had done but offered no explanation yet. The fellow I wrote to is using a timing tricker himself.

I hooked the sensor back up and cobbled up a crude intake heater system for now.

While I was at it I blocked the throttle at 2500 rpm. I could change resistors without shutting the engine off and the only effect I got lasted less than a second. Leaving the sensor out indicated -40 F and did produce a rich surge at high rpm and set a code. Otherwise there was no effect to timing, load, or rpm.

I also hooked a rubber vacuum cleaner hose to the exhaust and experimented with large amounts of EGR. I could not find a combination that produced a lower fuel consumption than the Scangauge was showing without the EGR. It dropped RPM and to get the RPM back required more fuel. But should I trust the Scangauge for that? I am not sure I trust the Scangauge to evaluate engine mods without knowing exactly how it calculates fuel used.

One saga ends and another begins.

Ernie

[popimp]

So has anyone else tried this? The chip modules that are sold on e-bay, are these just variable resistors?

[diamondlarry]

Most of the chips on Ebay are designed to make the car think it's cold so the ECU will dump more fuel in to make more horesepower.

[popimp]

I see. So did anyone else experiment with resistors to increase FE? If so did it work? I'm thinking about trying this. What resistors should I get, ohm wise?

[fabrio]

Hi boys

this is my first starter post, but I learn this forum from more years because, unfortly my english is very, very bad .

I am'not understand completely all yours posts, but, I want to say something that the IAT sensor have effect not only in the percentual fuel mixture, but also, on the advance of spark advance.

In constant velocity, the ECU to work in closed-loop, and value of the sensor IAT, do not increase and not decrease the fuel mixture, but only increase the spark advance with more eficent combustion and mor mileage.

I hope not to have said null of new

bye

fabrio

[88HF]

Thanks for the information! Welcome to gassavers. Your English isn't that bad. What do you drive and where are you from? You can use: http://www.google.com/translate_t
to translate pages like this to your native language.

[fabrio]

my English isn't that bad?.....haha....

you make me to laugh, thanks for the welcome. I am Italian, and I drive an opel tigra 1.4 liters.
My interests, is the aerodynamic and the fuel economy through electronic control like electric contolled grill blocking, and oxigen sensor signal modification, on which I am working.

ciao

fabrio

[88HF]

There are some "dialects" used here in New Orleans which are worse.

[fabrio]

to write for me, is a lot piu' simple that to read, many things escape to me also using the translator, therefore I hope, you have patience

[brucepick]

Originally Posted by usedgeo

Well I put on a few extra miles and fueled up. 45.5 mpg. The faux IAT temp of 233 F had virtually no effect...

I think maybe I'm missing something here
233 deg. F would make sense (to me) for a coolant temp.
Shocking as intake air temp.
Or maybe tell the ECU the coolant is just a bit less than 233 F, so the computer doesn't think the ICE is in danger of overheating.

Instead of faking the IAT, how about a circuit to tell the ECU that coolant is warmed up to get it into closed loop sooner?