[Dennis944]

Hi all, a little shoutout to the 968 community, hoping there's someone who could help me on my "no start" issue.

 

The situation:

I've got a rebuild 968 engine, complete with original wiring loom and ecu sitting in a 944S chassis. After completing the engine swap, the additional switched 12v to terminal 7 on the connector in the passenger's footwel and the wire for the tacho signal hooked up, I tried to fire the engine. It turns over fine, fuel pump is working, injectors firing, but there is no spark pulse coming from the ecu. 

 

Tested so far:

-Crank sensor tested with a oscilloscope, strong and crisp signal with little to no noise

-DME relay

-Wiring loom from ECU to ignition coil

-ECU tested on an other 968, fired up straight away, running smooth

-Switched and constant 12v and ground at ECU connector

 

Offcourse I understand that there is no way someone can know what's wrong (hooked up incorrectly or defective) by just reading what I've tested and what checked out correctly, but I hope that the distinctive "no spark(no spark pulse at coil), but firing injectors" rings a bell. To my knowledge it's quite uncommen and in the past all my ecu related problems which caused a no spark(and no spark pulse) situation also kept the injectors from firing.

 

Hope someone could point me in a direction.

 

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[Dennis944]

nevermind, got it fixed

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[ds968]

so what was the fix ? 

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[94SilverCab]

He lost me at ...wiring loom and ecu...

 

Jay

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[Dennis944]

Problem was difficult to find, but easy to fix...

The additional 12v on terminal 7 I hooked up was one that switched on when turning the contact switch on... But also one that switched off when I started the engine  :whine:  :whine:  

 

So every time I tried to start the car, power to the ecu was switched off, and was switched on again when I stoped cranking. The moment in which the starter stoped and the engine would still turn a bit caused the ecu to read a signal and fire the injectors once...

 

Now that the ecu is hooked up to a 12v source that is always switched on when the contact switch is on everything is running great

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[Bulti]

Ok Dennis, next time I've got problems with wires or connectors or any of that stuff you can expect me harassing you quite a bit ;-)

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