'99 Boxster Tiptronic not firing after engine overhaul

[78F350]

Originally Posted by Kice

Thanks! Is there a chart for the pins in the DME plug? Or is it best to go by the color coded cables from the CPS?

Maybe pin 78..?
I have a link to this in my folder of DME stuff, Says it's DME 5.2.2: https://www.renntech.org/topic/28597-porsche-996-dme-pinouts-and-connectors/

[Kice]

Thanks. I checked the relays in the trunk per Bentley manual and they all seem ok.

I also measured the voltage directly from the CPS connector when cranking the engine and it clearly produces a signal. So the CPS seems to be fine.

I am however unclear how to check if that signal reaches the DM, because when I disconnect the DME connector to check for the signal on the respective pins the car will not start at all. I guess need to jumper the starter for that test?

[blue62]

Originally Posted by Kice

Thanks. I checked the relays in the trunk per Bentley manual and they all seem ok.

I also measured the voltage directly from the CPS connector when cranking the engine and it clearly produces a signal. So the CPS seems to be fine.

I am however unclear how to check if that signal reaches the DM, because when I disconnect the DME connector to check for the signal on the respective pins the car will not start at all. I guess need to jumper the starter for that test?

Use a Multi Meter to check continuity and for short to ground on the respective pins

[JFP in PA]

Originally Posted by Kice

Thanks. I checked the relays in the trunk per Bentley manual and they all seem ok.

I also measured the voltage directly from the CPS connector when cranking the engine and it clearly produces a signal. So the CPS seems to be fine.

I am however unclear how to check if that signal reaches the DM, because when I disconnect the DME connector to check for the signal on the respective pins the car will not start at all. I guess need to jumper the starter for that test?

No, the CPS is a Hall Effect sensor, it only has to turn over to generate a signal, it does not need to run.

[Kice]

Originally Posted by JFP in PA

No, the CPS is a Hall Effect sensor, it only has to turn over to generate a signal, it does not need to run.

Understood, but how do i get the flywheel to turn with the DME (and hence the starter) disconnected so i have access to the DME connector pins?

[JFP in PA]

Originally Posted by Kice

Understood, but how do i get the flywheel to turn with the DME (and hence the starter) disconnected so i have access to the DME connector pins?

The starter should still turn over with the DME unplugged, but if not, reconnect it and back probe the pins on the DME harness plug.

[Kice]

Many thanks for the good advice !

I checked continuity for the CPS wires on pin 20 and 78 on the DME connector and there was none. I then realized that the connector for the camshaft position sensor has the same profile as the CPS connector -- and sure enough they were swapped. With the right connector on each sensor the engine started up rightaway!

For now its only runs on cylinders 1/2/3 - but i guess I should revisit all connectors on that side as well and then take it from there. Thanks again!