Re: A drowning V8 with a G40 error (motronic problem)

Hi Jeremy,

not the Ignition Point Sensor (OT-Geber) needs the teeth of the flywheel but the flywheel sensor does (Drehzahlgeber).

The Ignition Point Sensor needs a small pin mounted on the flywheel passing the sensor at every 360 degree turn of the flywheel. This pin indicates the OT-position of cylinder 1. So the OT-sensor is needed for two things: To indicate when the first ignition has to be done and for a proper indication of the crankshaft position together with the flywheel sensor (in this role the OT-sensor only is a kind of "helping" sensor or error corrector). Without the signal of any of them the engine won't start (or won't run).

So I have another thesis but it has to be noticed that this is quite unlikely: The G40 is, as far as I know, also a kind of error corrector or correction value between the position of the camshafts and the crankshaft position (measured by the flywheel sensor and the ignition point sensor OT). What if the relation between crankshaft and camshaft is incorrect (resulted from a damaged or wrong calibrated toothbelt (sweep)) and as a result the Motronic thinks that G40 is damaged (does it say implausible signal or no signal).

So is Lars sure that there is no mechanical damage at the engine and the camshafts turn as well when trying to start the engine? Perhaps it would be an idea to put the camshaft-coverages away and turn the crankshaft by hand to see if the camshafts are working correctly.

But please notice that this is only speculative.