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- - No spark (http://forums.pelicanparts.com/porsche-911-technical-forum/1097581-no-spark.html)

Quote:

Originally Posted by cabmando (Post 11390209)

Easy test for fuel is to jumper the fuel pump. You can do this at the DME relay or at the fuse panel to make sure it works but I'd still focus on the Speed and Reference sensors because they'll cause your no spark and they're what tell the ECU to signal the DME relay to close and bring on the fuel pump.

This.

On my car the sensors were only 8 years old, but they went wonky. New sensors fixed the issue and it is rock solid.

If the fuel pump is in question, squirt some either in the intake. If is sputters and tries to start, it is your fuel pump.

are the Speed and Reference sensors the same i only see Flywheel Impulse Sender for sale not reference sensor

Quote:

Originally Posted by porschedavid (Post 11390278)

are the Speed and Reference sensors the same i only see Flywheel Impulse Sender for sale not reference sensor

Yes they're the same sensor type. They're located on driver's side of the transmission up toward the top of the transmission. If you have to replace them and you're lucky, they won't be seized in the housing. DO NOT loosen the housing bolt that allows for adjustment of the sensors. There is a bolt on top of each sensor that you remove in order to take the sensors out of the housing. Again, make sure you make note of which is the speed and which is the reference when removing so you can connect them to the correct plug up by the intake.

Hi
Do the position and reference sensors control the fuel pump as well as spark

Quote:

Originally Posted by cabmando (Post 11389601)

The DME, not the DME relay, controls spark. The DME relay pretty much only controls your fuel pump. The DME (or the ECU... or Motronic... whatever) under the driver's seat gets signal from the Speed and Reference sensor. The speed and reference sensors let the DME know the engine is spinning. The DME sends a signal to the DME relay closing the relay coil which closes the contacts sending power to the fuel pump. The Speed and Reference sensors deal with spark as do the coil, distributor and the DME itself. The DME relay has nothing really to do with spark as I understand.

Quote:

Originally Posted by mysocal911 (Post 11389961)

There're two stages to the DME relay;

Stage 1 - Ignition switch to alarm module to DME relay - this sends #30 power to DME ECM, injectors, & idle valve
Stage 2 - DME ECM activates this stage to run the fuel pump, when ref & RPM signals occur

Quote:

Originally Posted by cabmando (Post 11390209)

Easy test for fuel is to jumper the fuel pump. You can do this at the DME relay or at the fuse panel to make sure it works but I'd still focus on the Speed and Reference sensors because they'll cause your no spark and they're what tell the ECU to signal the DME relay to close and bring on the fuel pump.

Quote:

Originally Posted by porschedavid (Post 11390674)

Hi
Do the position and reference sensors control the fuel pump as well as spark

Are you serious??

Thanks everyone.
Changed flywheel sensors now running

Perfect! Glad you got it fixed and sorry for the reply at #25.

Thats ok nick.
It got it sorted.Thanks David