Reply To: GT250 EFI DSpec Stalls at Idle after Warm Up
I have not seen an ISC dismantled but from the sound it makes when it is in operation and the fact that the “piston” is fitted to a threaded rod leads me to think that the ISC is a stepper motor with a “nut” fitted to its rotor. As the motor spins clockwise or anticlockwise the “nut” rotates with it, causing the threaded rod to move in or out accordingly. Even though there is a spring which acts to push out the “piston” it is not strong enough to do so. Below is an extract from the manual about the ISC. The manual calls it a solenoid but it does not sound like one.
The reported fault code is a strange one. First of all theΒ manual does not mention any fault code 306. Also that is a fault code from a previous run not this one. I have removed the column containing the current fault code to simplify the chart and in any case because all the entries in that column were zero.
I think the line which indicates an actual misfire is line 102 which shows the RPM dipping to 1515. The injector figures which are actually the time in milliseconds that the injectors remain open seem stable to me and only double right after the engine stalls at around line 111. I think that was a last gasp attempt by the ECU to get the engine to rev up again.
