Hey guys.. i'm going to post this in the carb forum to.

My LG4 '85 trans am is runnin pretty rich... I can adjust my computer-controlled carb, correct? A special tool is neccessary? Any help on this topic would be hot.

thanks.

 

No, not really. If you were to uncap the mixture screws anytunning you could do would almost all be undone by the ecm.
If you havent got a check engine light on yet try self cleaning the o2 sensor and see if it helps. Theres a wire by the heater blower motor (should be green or white) with a little connector on it. If you ground this wire you will hear the MCS click closed the carb will run very lean cleaning the 02 sensor and some deposits on the valves. Dont do this longer than 5 minutes and make sure the car is fully warmed up first.

 

Yes, you can adjust the E4ME, and it sounds like you probably should. However, you need to adjust the TPS and mixture control solenoid instead of the idle mixture screws as you would on a standard 4MV or MC. This will require a voltmeter and either an old style dwell meter or duty-cycle function on a multimeter (or an oscilloscope).

Here's how:

http://216.121.161.76/files/E4ME.pdf

 

Interesting, but wont the ecm undo the adjustments and go back to its base values?? Thats what Ive been told by people on this board and school.

 

Once the mixture conrtol screws are set to the proper range (as they should have been at the factory before they were capped) the main metering circuit mixture control is accomplished by the duty cycle rate of the mixture control solenoid. This control is done by the ECM based on TPS, MAP, and mostly O² sensor inputs. As long as the MC is adjusted to a base position that is within the range of operation of the ECM, the ECM will use teh MC to control mixture to satisfy the O². If the MC base position is out of range (or the TPS or O² inputs are faulty), the ECM can default to a full open MC as "limp" mode.

Ususally the TPS setting and MC adjustment is all that's necessary. There are some rare instances where the mixture control screws need adjustment, as with reman carbs, carbs swapped to a different engine, major modifications, etc.

 

Ok thats what I was thinking.


SSC