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Discussion Starter #1
I am interested in the parameters used in calculating mpg. I believe there are 3, engine load, distance travelled and rpm.

Engine load used to be measured from intake vacuum but after about 91 this changed. My question is how is load now measured? is it from the potentiometer on the maf? I think this must be the case as info from the potentiometer is fed to the ecu and the ecu supplies mpg? However, I have been through the pin out diagram for the ecu and there seems to be no conection to the mfa?

If anyone knows how this all works I would be very interested.

I have a 93 2.0l 16v 9a, owned it for 20 yrs so know it quite well.

Phil
 

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92 Clusters still had a MAP sensor on the back of the Cluster.

93+ gets it's signal from the ECU Directly and a result of the Injector Pulse Wiidth and other calcs.

There is a single Violet 1x connector that comes off of the Cluster and connects to the ECU.

Shown in Upper Right.

 

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Discussion Starter #4
For many years my mfa mpg was spot on. Then the potentiometer on the side of the maf failed. I replaced it with a genuine but used pot from a car being broken for parts. These pots are tricky to set up but I took my time and got it right. After this my mfa mpg is 5 mpg less than actual (tank to tank). I sourced another pot but the difference remained. I would very much like to have a correct mfa mpg and so am thinking of trying to modify the signal from the ecu to mfa.
 

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Odd. Maybe it is dirty, faulty or you really have some other issue and are truly getting 5MPG different.

One thing to also consider is that These calcs never accounted for Ethanol. While the Corrado was able to run up to 10% ethanol, it did nothing to detect content and or account for it.

So, it is known that 10% ethanol can cause 3-5% worse Fuel Mileage.

Just a thought.. Or perhaps failing 02 or other causes?
 
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