Air/Fuel Ratio suggestions

[Rukus]

I've been messing around with the air/fuel ratio on my BMW, and i was wondering if anyone had any suggestions. So far, i moved the air flow meter a couple notches looser. I also removed the cat, and adjusted the TPS. I plan on installed a freer flow exhaust and a cone air filter.

I have heard of people throwing in resistors on different things to "trick" the ecu. Such as the O2 sensor, air temperature sensor and such. I am not really indepth into those things and articles are but few.

I was wondering if anyone had any suggestions for me, considering that my ecu is a non chippable L - jetronic.

 

[KC Ron Carter]

Hmm,

To test for anyting other than the normal 14.7 to 1 ratio requires a wideband o2 sensor and the associated equipment. Yep I have one.


http://www.innovatemotorsports.com/lm1.php

Wideband o2 sensor.

With FI you want about a 12.5 to 1 AFR.

Normal narrow band 02 sensors will just do a lean rich signal for 14.7 to 1 ratio.

On cars with forced induction, FI, adjustments to AFR can be made by regulating the fuel pressure. Most just get a RR FPR, Rising Rate Fuel Pressure Regulator.

On cars without chipping the addition of a resistor in the ECU coolant temperature sensor will provide for a richer mixture.

Install an external resistor in the wire for the temperature sensor that feeds the Motronics (should be the one with the light grey connector) Resistor type is 270 ohm, 1/2 watt, "Gold Band" metal film resistor for Motronics Control Units with a Bosch code date of 342 or higher (production date after 9/83) and for Motronics 341 and lower, it is a 560 ohm, 1/2 watt "Gold Band" metal film resistor.

Third, the external resistor may be the source of a "no run" condition, if the solder connection breaks from handling the temperature sensor connector. This resistor is usually soldered just behind the connector and may be concealed under the rubber boot. A broken or bad solder connection will mean that your car will not start or run, and this could be an intermittent problem because of engine vibration. It may be better to carry a short wire with small insulated alligator clips on both ends in your tool kit to do a roadside repair.

You can measure the o2 sensor on the car by taping into the :black wire" from the o2 sensor.

Use a VOM, Volt Ohm Meter.

.6 volts is dang rich .3 volts is dang lean.

Here is an explanation on fuel control systems.

http://www.kemparts.com/TechTalk/tt07.asp

Yep, I have a Dyno TOO.


Later,