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2003 Smart won't start after engine rebuild

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  • #16
    Originally posted by Akura View Post
    OK, I've checked the ignition timing today with a strobe light. It looks like the spark comes way before TDC of cylinder #1. Is that normal?
    How far is ''way before ''? Lots of advance isn't required for starting (over advanced, they can be felt kicking back against the starter motor). The exact value will be determined by the ECU but I'd expect it to be close to TDC.

    Originally posted by Akura View Post
    I removed the crankshaft position sensor in order to check the "target" on the flywheel without removing the gearbox again. When cylinder #1 is at TDC, the target is at ~10 degrees BTDC. Does someone know if this is correct?
    Suspect that is wrong. If the ECU doesn't get the signal until 10deg BTDC, how can it then adjust to say, 25deg BTDC? For that, it would need the signal earlier so it could then place the spark at 25deg. At 10deg BTDC it would have to travel back in time!
    Have a look at how to set up a trigger wheel for a MicroSquirt application for more detail.

    Originally posted by Akura View Post
    I also had access to a MB Star computer, it said my intake air temperature sensor is dead (reads 8000 ohms which indicates a -30C outside temperature, instead of 20C). I've ordered a new sensor but I'm not sure it could prevent the engine to start...
    That would make it massively rich. However, if after initial cranking the fuel was then disabled and cranking recommenced, there should be a point where it becomes dry enough to at least offer to fire.

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    • #17
      IAT is part of the electrical system and its firerele it may be defective - possibility large IAT not break down but wire stand you have reached (lowered / increased motor).
      Check that the connectors are installed (sensors corespozatori) - I happened mess and so I struggled to launch engine ,a while.
      IAT is the intake manifold and has 2 wires. It has 5 Kohm +/- 10% / 25 C, it can check by the ohmmeter.
      Last edited by mottofreee; 18-04-17, 09:42 AM.

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      • #18
        Kindly advise your no 1 cylinder timing in degrees when checking using strobe light.

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        • #19
          Can be used for strobe and belt pulley .

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          • #20
            IAT sensor has same connector as coolant and outside temperature sensor. They all use same thermistor so signal will be same if temperature is same. On IAT and outside temperature sensor it is possible to replace the thermistor which only costs a few pence depending on where you order. Resistance at +25C is 3000 Ohm. Beta value 3988K.

            Outside temperature sensor. The white paste is heat conductive grease.
            http://uk.rs-online.com/web/p/thermistors/5288508/

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            • #21
              Originally posted by Akura View Post
              OK, I've checked the ignition timing today with a strobe light. It looks like the spark comes way before I also had access to a MB Star computer, it said my intake air temperature sensor is dead (reads 8000 ohms which indicates a -30C outside temperature, instead of 20C). I've ordered a new sensor but I'm not sure it could prevent the engine to start...
              8000 Ohm is 4.6 Centigrade.

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              • #22
                It is ambient temperatur sensor ,not intake temperature sensor .
                Star detect intake temperature sensor is faulty .
                Intake temperature sensor are 5000 ohm (5Kohm) /25 degrees / +-10% => 4500 ... 5500 ohm .
                The measuring device indicates a value in range(4500 ... 5500) @ 25C (maybe be 24C ) ?

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                • #23
                  If plugs are wet with fuel and you have sparks, then the missing ingredient would surely be air!

                  Are you sure you've reconnected the throttle body?

                  Missed that plug once myself!

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                  • #24
                    Mottofreee is right. Inlet air temperature sensor has different thermistor to outside temperature sensor. I have just confirmed by measuring on my IAT sensor removed from my 2002 Cabrio 450. Resistance at +25C is 5000 Ohm. Beta value 3988K.
                    8000 Ohm resistance is 13.1 C.

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                    • #25
                      Fellows,

                      Problem is solved: http://www.smartcarofamerica.com/for...94-post14.html

                      Thanks to all of you for your support

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                      • #26
                        Originally posted by Akura View Post
                        Fellows,

                        Problem is solved: http://www.smartcarofamerica.com/for...94-post14.html

                        Thanks to all of you for your support
                        So the cause was low compression. 9 bars is way too low. Should be around 12 bar.

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                        • #27
                          ''I guess the first rings sets had a problem, or maybe I've done something wrong when putting them on, I don't know...''


                          Is this a case of the wrong sized rings being fitted?

                          I'm pretty sure engines have fired on compression pressures of 9bar or lower. Was this too low for the ECU to register sufficient angular velocity variation?

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                          • #28
                            +1 with mottofreee

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