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I've seen them before, there rip offs. usually if the say that their device modify's the air/fuel ratio, its just a cheap resistor in a box, and its definately not worth it. if your looking it into a chip for your car. i would stick with know brands, like diable, jet, etc.... I made the mistake of buying a device very similar to that. all it does is trick your engine into thinking it is receiving cold air. which can be dangerous under the right conditions. Because since your car never knows what the actual temperature is, it may run too lean. so all in all it sounds like a dumb scam.
 

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a resistor mod will actually make your car run richer, not leaner. If it thinks the incomming air is cooler (i.e. more dense) it will think there's more air in the cylinder then there actually is and dump extra fuel. Unless you were running kinda lean in the first place, all you're really going to do is waste fuel and not completely burn the fuel you do pump in, which will eventually foul things up faster (carbon build up). May even mess with your emissions.

When tuning a vehicle, the object isn't just to deliver more fuel, the idea is to find a way to deliver more air and then adjust the fuel mixture to ensure it's all burned without leaning out.

-Dan
 

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Plus, the O2 sensors have the final say in what the air/fuel mixture is, and will readjust if they sense a rich condition. the resistor won't do anything at all. Iv'e tried it on my own car.
 

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Originally posted by silvapain@Jan 5 2004, 06:22 PM
Plus, the O2 sensors have the final say in what the air/fuel mixture is, and will readjust if they sense a rich condition. the resistor won't do anything at all. Iv'e tried it on my own car.
Granted the MAF and the O2 sensors determine the air:fuel mix.

the MAF sends an analog DC voltage to the computer of 0.5 - 5V depending on air flow the O2 sensors send a voltage of 0-1.1V where <.4V is lean and >.6V is rich.

Now if lets say i give the computer 5v dc as the MAF input i think that will give 100% duty cycle for the injectors and ofcourse make it extremely rich (on a prettty much stock setup). I dont know what will happen when the O2 sensor notices thate its rich, if it does have higher priority then the MAF input then it will componsate.

Now what is to stop me from giving the computer a 1V for O2 sensor input and a 5V for the MAF input? This should therefore make the car rich constantly. Yes terrible milalge will result and carbon deposits become a problem. But if one wanted to control the fuel to air mixture of the car manualy then it can be accomplished this way.

Right?

Thought? Comments?

Actually to not take away from this thread i will start a new one discussing this scenerio, please reply to this post in that thread.
 

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Originally posted by qaz-+Jan 27 2004, 10:31 PM-->QUOTE (-qaz- @ Jan 27 2004, 10:31 PM)
<!--QuoteBegin-silvapain
@Jan 5 2004, 06:22 PM
Plus, the O2 sensors have the final say in what the air/fuel mixture is, and will readjust if they sense a rich condition.  the resistor won't do anything at all.  Iv'e tried it on my own car.
Granted the MAF and the O2 sensors determine the air:fuel mix.

the MAF sends an analog DC voltage to the computer of 0.5 - 5V depending on air flow the O2 sensors send a voltage of 0-1.1V where <.4V is lean and >.6V is rich.

Now if lets say i give the computer 5v dc as the MAF input i think that will give 100% duty cycle for the injectors and ofcourse make it extremely rich (on a prettty much stock setup). I dont know what will happen when the O2 sensor notices thate its rich, if it does have higher priority then the MAF input then it will componsate.

Now what is to stop me from giving the computer a 1V for O2 sensor input and a 5V for the MAF input? This should therefore make the car rich constantly. Yes terrible milalge will result and carbon deposits become a problem. But if one wanted to control the fuel to air mixture of the car manualy then it can be accomplished this way.

Right?

Thought? Comments?

Actually to not take away from this thread i will start a new one discussing this scenerio, please reply to this post in that thread. [/b]
Yes and no.

If you were ever seeing 5v, first off all, you would be in open loop, which means the 02's aren't even used. The EEC goes solely off the fuel base table Second, you will probably have pegged the MAF, which means a lot of that air would not be measured and the car will actually go lean.

AND there is one thing not considered: most EEC's have a cap at 980 AD counts, whcih is liek 4.79 volts...so after this point the EEC would set a failed MAF code and the above condition would occur. Now I can make this go away and set the limigt at 5v...

Anyway, the stock O2's are not wideband O2's but rather HEGO or EGO, Heated Exhaust Gas Oxygen sensor. This is a sensor in the exhaust system, before the catalytic converters that measures the content of the oxygen in the exhaust. The output of this sensor is from zero to five volts. The sensor only has the ability to tell if the air-fuel mixture is either rich or lean of stoichiometric. It cannot give feedback as to what actual air-fuel ratio you are running is. Regarless, in open loop, the EEC has NO IDEA how rich or lean you are.

This also has NOTHING to do with injector duty cycle...


Also, the point of teh resistor mod, which yes it does have the sideffect of adding SOME fuel in, is to add timing by tricking the EEC into thinking it is a colder/higher density day...but how then do you compensate for warmer days and what not? The system is set up the way it is for a reason...you may at times end up with too much timing and do some damage, since now you are taking control from the control system...
 
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