Maybe bit ott to big of the apple

[Xlexustech]

I doubt any of the pin this and circuit that means much to anyone without a wiring diagram to go with it for us to look at. Maybe the guys that do this professionally can, but don?t I keep this in memory.

Updte, So far ived added a new ground form batt to engine, Removed cleanded and refit both grounds on the back of the Cyl Heads and lower engine drivers side. All tested solid grounds, replaced the FP sensor with a higher pressure part (same unit just supports 3K psi stock on LT4) validated Pins X2-28 and X1 41 to the ecu, these are for the high pressure circut. I also validated X1 pin 2 to the low pressure sensor. I added a new harness on Drivers side injectors which includes the high FP sensor circuit. Next up I am looking for a new OIl pressure sensor pigtail, just to be through, I dont like the way the connector looks, engine installer was not kind to the harness it seems.

EWD for 5v reference circut attached. I ppurchased a susbscritpion to ALLData so I would have access to all docs required. If another EWD is more helpful I can get it

[Xlexustech]

As noted it was not the ECU... For those in the future who have this 95050 issues, please check your 5V referance circut. Its shared across several sensors. SO you may find a short in a compley unrelated sensor that drags down the entire reference circuit.

For example although not in my case the AC pressure sensor shares 5v reference with Fuel pressure. It that Air conditioning sensor is shorted it can kill the circuit.

[edcmat-l1]

OK, so what was it?

[gtstorey]

As noted it was not the ECU... For those in the future who have this 95050 issues, please check your 5V referance circut. Its shared across several sensors. SO you may find a short in a compley unrelated sensor that drags down the entire reference circuit.

For example although not in my case the AC pressure sensor shares 5v reference with Fuel pressure. It that Air conditioning sensor is shorted it can kill the circuit.

I thought that was a problem that you had eliminated when you posted "I traced all sensors that share the 5v, I tried isolating each one". If you are missing 5v to a sensor, one of the first steps is to disconnect the others on the same 5v bus to eliminate one of them pulling it down.

[Xlexustech]

OK, so what was it?

Of the three circuits that share the 5V reference form X1 41 two of the sensor connectors were butchered. I harvested a new oil pressure pigtail from a factory harness I have and got a new D/S injector harness. I also cleaned the grounds behind each head and behind the air pump. Lastly I ran a new ground from the Battery to the block.
SO what does all that lead to... A bad 5V referance signal is the stamp I would put on it. 'Bad' being unstable 5V value.

[Xlexustech]

I thought that was a problem that you had eliminated when you posted "I traced all sensors that share the 5v, I tried isolating each one". If you are missing 5v to a sensor, one of the first steps is to disconnect the others on the same 5v bus to eliminate one of them pulling it down.

I did, what i did not know is any sensor in the shred circuit could short and the ECU would stop sending reference. Thats exactly what happened here. On two circuits the oil pressure and fuel pressor sensors. Both of which had damaged terminals. a comnobation of those two + weak ground to the block.