fsd calibration resistor ?

[Jim P]

I would like to install a potentiometer in place of my calibration resistor in my fsd. When I was rebuilding my motor I had the resistor out and it was a #3 so I am thinking that I could get quite a bit more fuel with the potentiometer. My fsd is still mounted to the pump because my pump is still under warranty and I don't want the dealer to someday say that a remote fsd cooler voided my warranty. From reading the article in the members area, I know which wires to attach the potentometer to but I was wondering if I can follow these wires back to firewall and cut these two wires and attach it here. I would also like to leave my original resistor in place. Its looks like it would be a real PITA to get out while the fsd is still attached to the pump. I guess my biggest question is whether these two wires actually attach to anything inside the fsd or if they only attach to the resistor.

Also I know it has been kind of unclear whether the computer would recognize a new resistor without doing a tdc learn. Has anybody tried it to know for sure?

Jim P.

[ucdavis]

1) use of potentiometer would only be "read" by PCM periodically or on loss of memory. Just changing the resistor doesn't automatically change the value stored on computer, i.e. PCM doesn't use the resistor value interactively (WTH not is anybody's guess).
2) resistor shunts between the two wires, that's all. so you could interupt the two wires anywhere & install the new resistor or pot (would now be in parallel w/exist'g).
3) due to PCM periodical check of resist value, using a pot (I'm assuming you are intending a variable pot to account for ambient driving conditions) won't affect the value stored in PCM except randomly, and then only on an instant-read/store basis.

That's my understanding; your mileage may vary.

[ucdavis]

Also, if I were you I'd add a remote fsd & harness. Leaving the PMD for warranty purposes leaves all the bad design of that setup intact. Leave the old PMD, and install new fsd/harness; then if you have warranty issues, unplug remote & plug in PMD, then go for service. This setup also gives you a spare fsd in case of SFD (sudden-fsd-death).