Ok so I been reading the boards and I put on a three wire o2 sensor on my 1989 iroc 5.7. I noticed that the oil pressure sensor looked a little rough and replaced the sensor above the oil filter. Car was running before I did this and when I tried to crank it after I got it off stands the car would not crank. It will turn over but will not crank. I have the vats turned off with a prom from tpiparts I called him and he said if it was a vats issue it would have a code which it does not. Just shows 12 when I flash the ecm.
I am so confused on the threads as it seems there are so many opinions on this subject.
So i guess what I am asking is and I probably know the answer but would like advice.
I am assuming the switch I bought is bad as it was the only thing I touched yesterday as I have still not wired the O2 sensor. So if that is the case does that mean the fuel pump relay is bad and that possibly I did not know until I messed with the oil pressure switch?
I tried to read threads and my service manuals when I jumped the 2 end terminals the fuel pump came on. So exactly how do you troubleshoot this issue or is it safe to say just get a new pressure switch and get a fuel pump relay then go from there. Has anyone had this problem and where did you begin when fixing the problem.
thanks

 

You could have a faulty oil pressure sensor. If it doesnt detect oil pressure ( I think 4 or 5psi) then it will cut off the fuel pump to protect the engine. Have you tried putting the used one back in to see what happens?

 

No not yet if u am going to do it again probably just going to try another new one. I am 100% sure it will work and if it does run does that mean rhe relay is bad or does one work independent of the other