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Old 03-19-2006, 11:50 AM   #1
3v's are slow
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Misc items in regards to EEC tuning..

Found some items on the net today that I thought I would put in one thread.

Feel free to discuss or let me know if it is incorrect info.

Originally Posted by Raymond B
Parameter Name: MAF_Function
Processor : All eec-iv & v
Paramater Type: Function
Bin Location : 6DE2(A9L)
Size : 2 col X 30 rows
X-axis : MAF Voltage
Y-axis : Mass airflow in kg/hr
Data scaling :
Definition : It is a function that allows the processor to determine how much air mass is entering the engine based on a voltage signal from the MAF meter.
Program Context: The meter compensates for temperature and density changes in the air mass. For a given air mass the voltage signal will vary for varying temperature and density. In turn the computer can compensate for these variances. Load can also be calculated based on the MAF function and Engine Displacement. (Actual airflow/Theoretical aiflow). Logically, the MAF function is probably also linked with the data from the MAP sensor.

Tuning Importance: This is one of the functions to tune if you are having driveability problems or have switched to an aftermarket meter and/or larger injectors. The MAF function has been one of the most talked about functions in regards to tuning. It plays an integral part in a vehicle's performance and driveability because this is how the computer knows what
quantity of air is actually entering the engine. It is very important that the function be accurate. So what can be done from a tuning standpoint. Well, if you have a Pro-m meter that is calibrated for certain injectors you can enhance performance by entering the correct MAF function for that specific meter. This is done by taking the 9 pt. flow sheet that comes with the meter and inputing it into a special excel spreadsheet that will convert it to a 30 pt flow curve. These 30 voltage and airflow values can then be put in place of the stock values in the software. From there you can fine tune problem points. If the car is running rich at idle, you can attempt to lean it out by multiplying the airflow values at idle by a decimal number less than one. For example, 23.4462 kg/hr X 0.9 = 21.1016. Entering this new value will cause the computer to think that there is less air entering at a given voltage and initially determine that less fuel needs to be injected. However, the O2 sensors will have the final say in what occurs. Multiplying the y values by numbers greater than one will enrichen.
Even if you have a stock meter, it can still be tweaked in the same way. The eec-tuner basically takes the place of an air optimizer but with an infinite adjustment range.
Originally Posted by fred 4 pt 3
MAF transfer comments:
Simply put, get your MAF transfer curve right first. It gets complicated by the position of the unit in the intake path. The suggestion of setting your adaptive strategy limits to .49 and .51 (along with a neutral mixture) and going for a cruise has merit for finding a bad spot in the maf curve. If you find that your correction that makes the car run right makes for a non-smooth plot of data, suspect that you have a fierce air turbulence near that flow, and try repositioning your MAF sensor in your intake path. A 45° twist can do wonders for a C & L.

Idle comments:

As for idle smoothing, I find the high injector slope parameter a wonderful tool, and wield it just like an idle mixture adjustment. Generally it should be higher numerically than the fixed injector size. Higher goes leaner (shorter pulsewidth figured). I find that the injector offset point (the point that the idle slope begins) is mostly correct if you run a fuel pressure near 42 or 43.

In supercharged cars that stress the fuel pump that way, it's common to run 38 or 39 for fuel pressure, and the big injectors have difficulty tuning up. It's easier to get a FI fuel pump and AFPR it to 43 or so, than to try to tune out the effects of lousy atomization. Also, the injector requirement is less at higher pressure by SQRT(p(1)/p(2)).
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Old 03-17-2009, 07:15 PM   #2
Dale McPeters
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Yep I have Raymond's original post of this printed out in my little black book...his original post went in to a lot more detail about how to actually tune the maf by using lambses...kamref or WB.........

That post was from about 5-6 years ago or so I think..........
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Old 05-08-2009, 08:15 PM   #3
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Wonder if you use the high inj slope parimeter for idle like you would for a carb. And shoot for highest vaccum reading with a smooth idle? Thx clyde
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