Good Morning and Happy New Year to all...

I have a "rescue" thread for this same (beautiful water damaged xkr) and have (thus far) come down to 4 MAJOR problems (JGate adjustment, No Fueling via FPModulation and a terrible Parasitic Battery Drain, intermittent starter issue) and thought I would start individual FOCUS threads on each and update that main thread with findings later.

I have so little time (and sun in these winter months) that every bit of time needs to count - so I like to have something of a plan of attack with the time I do have. This Sat and Sun are my days coming up...

ANYWAYS...Here goes it.

My fuel pump will not run unless I run a ground wire from the YR wire to a ground coming back from the pump. Without it, pump does not run and if running, and ground is disconnected, pump will shut off and car will die, fuel starved. With the temp ground wire to earth, she runs very nicely, considering. Please ignore the circle of the connector in this diagram.





Thanks to folks here I have come to a limited understanding of duty cycle, PWModulation and the controlling unit, FPModule located in the boot and to a degree, the fueling system generally. IF the fuel pump would run and it was over or underfueling, I would get an osilloscope (which I may down the line) to check for pulse and duty cycles. But I get nothing at this point.

There are these 2 White wires going into the FPModule. Running thru different connectors from the ECM to the boot. I can trace all these. They are described this way (see 2nd photo)... IT SEEMS these are all readable positive voltage that,,, for now,,, even if it is a fluctuating DMM value,,, I can just see if I'm getting values, for now??? Will that work? Osilloscope later?



Then,,, and I don't even KNOW what to think about this as I have never seen or checked it,,, the Pressure Sensor on the rail (IP sensor in photo), how it talks to the ECM and how that info is translated and then used to regulate pulse rates... Also,,, where is the PIS1 connector found? It seems like a very important multi-component junction. What should I be looking for in the IPSensor and will a failure here result in a failure of the grounding PWModulation signals from the ECM to the FPModule?


What else do I need to be thinking about?

It's a large file... But I will try and attach the 2003 EG here. All of these diagrams come from sec 4.2 and 4.1,,, Engine Managment...
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