Hello all. Does anyone know how to fool the ECU in a 2k1 Accent w/1.6l into thinking it is still cold??? When I first crank the car up and stomp the gas the car has a whole lot more power than when it has warmed up. I figured the would be a way to fool the car into thinking it was just cranked, that way it would run a faster ET.

Thanks in advance.

 

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EDIT: -> Hopefully somebody else has time to expand on that.

 

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Just let the car kool down,... push it towards the line, then start it right before you race

I do not recommend you do this, since the car is designed to work at certain temperatures.

 

The question is... is it faster because the engine is cold or is it faster because the ECU is making changes to the fueling / timing?

If it is ECU changes then you have some options.
1. Generally increase fuel flow by slightly increasing fuel pressure... but OBD II will "adapt" to this and you will get no gain after several weeks.
2. Set up a resistor with a switch inline with the air temp and / or engine temp sensor and switch in on when you need it. Miata boys use this setup to switch on only during boost... to add just a little more fuel only under boost... otherwise the OBD II will adapt.

 

Cheuk has really hit the spot in a tuning aspect BUT i'm not sure that you realize whats happening under your hood.

When you first start your engine... all components that make up your engine are at ambient atmospheric temperature. Well, since it is an Internal Combustion engine, key word combustion, it's gonna heat up everything in your engine bay. Say after 10 min. everything that's going to conduct heat (pretty much anything metal and eventually plastic) is going to be scorching hot and things like plastic are going to be at least hot.

So what does this all mean? A hot engine isn't as powerfull? Well, it's not the hot engine that's reducing power, it's the hot AIR!!

Think about it like this...Why do people with any kinda forced induction run with an intercooler? Well an engine will make more power if the air is more dense like cool air. Compressors HEAT the air due to friction during compression. So intercoolers which are heat exchangers transfer the heat and make the air COOL.

So what this all means is it seems you're making more power when your engines cold but in fact your engine hasn't heated the ambient air inside your engine bay. I'm not saying go buy an intercooler for your NA engine, but perhaps a cold air intake would be nice. It's not the perfect answer but a start. Your engine has temp. sensors that tell the ECU how hot/cool the air is. The stock engine management system will compensate for the change in air temp by adv. or retard the timing and other little tricks to meet factory settings like fuel economy and so forth. Chances are, your ECU wasn't tuned for maximum power.

So what was Cheuk talking about with the Resistor?
Temp. sensors are a type of transducer that take physical/chemical engergy and make it eletrical engery. As the temp. changes, so will the resistance of the temp. sensor. By ADDING a resistor you can offset your temp. sensor resistance and make your ECU think that, hey it's still cold out here. I'm unsure of the parameters that determine more fuel or less but that's the idea.

If you're still reading this then congratulations. You are now the SHOP HERO.

Rich.