Using the EFI Correction Box

[Wade Nelson]

I worked for Motorola.

[EuroDat]

Please tell us more about how you got your final value using the driving by feel method? I think it would also be important to see what resistance works bets with long-distance driving, which is what I do. Perhaps there is a way to set up a correction box for both situations?

It wasnt rocket science, just doing acceleration tests in 4th gear (1500 to 4500 rpm) and adjusting till I got best results. Its running a little rich. I did the testing on a long straight stretch of road. It has made the engine run a lot better.

I would like to fine tune it on a dino, but first I need to upgrade the old exhaust and change some dodgy connectors in the EFI wiring.

I was thinking on making a box with a doulble circuit like your diagram to create a Econ/Power. Then a switch to make an Econ/Power function that you see on some modern systems or a contact that would be activated by the gas pedalpassing a certain point.

Chas

[Captain Obvious]

Then a switch to make an Econ/Power function that you see on some modern systems or a contact that would be activated by the gas pedalpassing a certain point.

Chas

You've already got one of those... It's called the throttle position switch.

That's exactly what it does.

[TomoHawk]

For reference, I will submit what the expert on HybridZ said about using this diagnising gadget:

For seat-of-the-pants tuning, with POT at say 250 ohms, you can then flip the switch at WOT and feel/hear/see any difference in how the car ran in real time. You would just narrow down the resistance value to what the engine likes best using that method and then once you narrowed it down, you would just add a resistor with that value in series to the water temp sensor. After that WOT tuning is done, only then do you move on to fiddling with AFM spring tension for part throttle cruise. On the dyno, just turn the dial till the engine makes max power.

[TomoHawk]

Thanks EuroDat, for sharing your technique. Unfortunately, my "seat" must be less sensiive than yours, so I can't really tell any difference when small resistance changes are made. I would need to some a technique that is more quantitatve or uses something you can measure- like dynomometer tests. Large changes are obvious, as the engine is over-rich and gets less smooth..

[Zed Head]

If your stock AFM and ECU and engine components are "in tune" and working well together you won't notice any improvement from the potentiometer. It's only a benefit if you have a lean condition that needs fixing.

[TomoHawk]

Then my stuff is probably working just fine. Aside from an occasional treatment of the electrical connectors, nothing more is necessary. "ll keep the box for show or if I go to to a race track.