JG911 wrote:
Hello Jim when i was round helping my friend with it he says the sensors are fine.
So looking towards the ECU then

hi,
Here is a simple test to see what is happening to the coil circuit,,,
Disconnect the wires from both sides of the HT coil, TERM 15 (usually a Black wire +12v ign feed to coil) & TERM 1(usually a Green wire this is pulled low then paused then low again, by the ECU/Amp to give mutual induction thus HT from the coil windings,,, ( leave the king lead in the coil tower)......Put a 21watt (indicator bulb) across the wires that you have removed from the coil.
Carefully insulate the connections you make, get some one to crank over the engine and observe the bulb........as you have said you have no HT, almost certainly the bulb will NOT light at all (please follow the instructions further down on continuity test of the wiring)
if it comes on and stays BRIGHT during cranking this shows a short circuit on the Green wire to GND this will result in a momentary production of HT (WHEN YOU TURN ON THE IGN).... then NO more as the coil is not being sw'd on and off which it requireS to give HT.
try this site for ALL motronic info ...
http://www.frwilk.com/944dmehere is pin out of A 911 ECU
before you condem ECU do a Point to Point continuity test on the wiring
Attachment:
motronic pin out.jpg
Here is a pic of a 911 ECU,
Attachment:
911 ECU PIC.jpg
is your ECU the same part no ?
any probs feel free to ask
Jim,
Are the ign drivers inside the Motronic on this model ? i know they are on my 87myr 944 2.5n/a, i'm not sure on a 911 !, they may have a external ign amp !!
Not sure, I think this era run very similar management to 944s. But I think the earlier cars run electronic ignition via a separate module & mechanical ignition. Then they ran DME 944 type system, in which case the ignition/coil drivers are internal.