Cadillac Repair: 96 caddi stalling /no start condition, oil pressure switch, fuel pump relay

Question
i have a 96 caddi sls 32v northstar. it will start normally most of the time then just stall as if i turn off the key.somtimes it will start back up and other times i have to turn the key off and on several times to start the vehicle. i have replaced the fuel pump and it exhibits the same problem.i tested the fuel pump wiring and found that it is recieving power to the fuse/relay but not always to the fuel pump itself i know it should get power for 2 seconds and when it does the car will run fine till it dies again then i will have to turn the key off and on again several times somtmes only getting just a fraction of a second of power to the relay and somtimes it will get full power again and run. i have noticed many people with a similar problem on here believeing it to be a fuel pump but i know this not to be the case in my situation anyone know the problem??

Answer
Here is how the fuel system works:

when you turn ON the ignition key the computer sends via a relay 2 seconds of battery voltage to the pump to prime the fuel system so the car starts easily.

Once the engine is running the ECM computer bypasses the fuel pump relay and sends battery voltage down to the oil pressure switch  which is now closed due to oil pressure being exerted on the switch due to the engine running and this battery voltage passes thru the oil pressure switch back to the fuel pump.

Possible fault in the contacts within the oil pressure switch.

There is a way to run battery voltage straight back to the fuel pump for TEST PURPOSES ONLY to make the fuel pump run all the time.



If you are mechanicaly inclined or know of someone who is, You will need simple electrical schematics, Test procedures and picture locations of the components within the system that is causing you problems of which can't be done on this website which only allows one picture. I do not have a website so you will have to e-mail: onlineautohelp@msn.com in order to obtain the information.