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  • getting a little closer

    i learned a few things from chris sunday and played around abit with some different bin files. there's one problem that comes up every time regardless of the bin file . when the car is cool it runs pretty well . alittle rough in the idle and afr's are just right under boost . after the car gets good and warm it's a completely different car . very erratic idle afrs going from 13-18.5 and it gets super rich under boost . afrs of 9.9-10.3 . i'm really starting to lean toward sensors because of the cool to hot running difference . what sensors play a significant part in the operation of the ecu between cool and hot ? i know chts is a big one what about the coolant sensors or the oil temp sensor ?


    boost. does a body good!

  • #2
    Only CHTS, that's all it uses for engine temp. There is a temp enrichment value in the ECU that can be adjusted... but I've never messed with it very much.

    The oil temp and coolant temp are both only for the dash gauges as far as I know.

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    • #3
      thats what i thought . so the chts is the only tempurature dependant sensor that ecu see directly , right ? what should the output voltage of the chts be ? and what does the ecu look for as far as voltage , temp vs volts ?


      boost. does a body good!

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      • #4
        Actually the ecu also keeps an eye on the fuel temp sensor.

        Chts- Colder the engine is the more timing and more fuel the ecu adds to the base calculations. I dont think it adds any fuel when the chts reads hot though.

        FTS- More than likely the hotter it reads the more enrichement the ecu adds. You might check this sensor to make sure its good and hooked up.

        FSM will help you test both.

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        • #5
          i don't have a fuel temp sensor anymore .


          boost. does a body good!

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          • #6
            well you could always try unscrewing the chts and keep it plugged into the harness

            zip tie it to the fpr or something, the ecu will read the engine as cold at all times but at least you could fix the erratic enrichment

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            • #7
              jjewell wrote: i don't have a fuel temp sensor anymore .
              I would suggest that you try putting it back on if you can. Or maybe rig up a resistor so the ecu at least thinks it's there. Just one more thing to rule out of the equation.

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              • #8
                temp sensor is back in and it is no better i need to get my lm-1's rpm converter hooked up to get a little more understanding about whats going on . 10psi and my afr's are around 10.5 . afr's at idle are around 16-17 and it rough as hell . 17 psi i had afrs around 11.2 but it started to feel rough as well . i keep thinking sensor issues but i don't know . anyone ever do a blow through maf like right near the throttle body ? it would be nice to rule out the intercooler and blow valve system for good .


                boost. does a body good!

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                • #9
                  Ok lets go over the basics.

                  Are you absolutely sure you have no leaks anywhere between the maf and the engine?

                  What injectors and afm are you using. What have you changed in the bin file? Is the o2 sensor hooked up? Lm-1 calibrated? no exhaust leaks?

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                  • #10
                    `

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                    • #11
                      this car has always had a slight miss at idle and at steady thottle cruise . i thought that the romulator would fix much of it but it has only gotten worse . i have changed the engine, fuel system, intake , turbo, all sensors at some time or another or swaped out with parts from other running cars and i still can't find the source . the only thing i have not been able to swap out is the coil signal wire from the ecu to the coil . i have also removed all vacuum from the engine to try to figure it out and there was also no change.


                      boost. does a body good!

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                      • #12
                        all sensors, including the CAS? I don't think that's your problem though.

                        What have you done with the computer? Is it a replacement unit? I had HORRID idle problems until I actually replaced the comp.

                        I've also found on a few cars where some of the wire pins going into the ecu connector are a little loose. One was so bad that it'd stall the motor out if you touched them or hit bumps hard. Thirty seconds with a pin-tool (a flat tip would work too) and it was fixed.

                        I would idle the motor, and push on all of the wires going into the ecu. See if you can tell a difference.
                        vg33et -blew some chunks outta it, then gave it all away.
                        2009 370z touring/nav/sports

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