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Cap to trick PCM?


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Posted

So I was reading the FSM for my vehicle and it adjusts charging voltage based on load and a temperature sensor under the battery. If I where to install a cap and maybe put a resister where the temperature sensor is would there appear to be more load than there is and could I possibly trick the PCM to charge at 14.4 all the time? I don't have any severe voltage drop so I dont think it would be doing anything other than possibly this and slightly stiffening the voltage.

Side question, is putting a small cap on my mids/highs amp a good idea because my sub amp is possibly sucking power from it? EDIT: My guess is no because power is just going to go in the direction of least resistance, but let me know!

Posted

okay so I found this thread:

http://www.stevemeadedesigns.com/board/topic/105427-using-diodes-to-step-up-voltage/

May not need the cap at all, just the resistor where the temperature sensor is. There seems to be some debate on what value resistors to use. I found some specific values for my vehicle on a Jeep forum but what if i just put a variable pot knob there instead so I can change it myself in case it starts doing something wacky? I suppose I could just measure the resistance of the sensor with a DMM and then find a pot that has that value in it's range right?

Posted

More information! It appears the sensor is given a 5v signal and the PCM adjusts voltage depending on how many volts it gets back between 0-5v. So basically I need a pot that can handle 0-5v at what I am assuming is a pretty low amperage. Having it adjustable will be great because if something goes crazy with the alt/battery/belt/etc. I can just pull over and adjust it where with a resistor I would have to take it out.

Where do you guys think I should start? 10kohm?

EDIT: Can't wait to get home and try this. I think what I am going to do is run some wires to the dash that go to a switch so I can go back and forth from the potentiometer (possibly also in dash) and the sensor so I can have a "normal" and "adjustable override" setting.

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