Is that okay for it to be at when Its been runnning for a while and at idle. It goes up to 45 when i drive but just curious as to the idling at 30psi

 

Should be fine, according to my manual.

 

I've heard that a smallblock only needs 5-10 psi at idle, but I am not sure if there's any truth to this.

 

Hey kowboy59, 30 PSI at idle is fine. Now 5-10 PSI I think is stretching it.
If my '88 GTA ever drops below 20 PSI, a switch on the oil sender shuts
off the fuel pump thus saving the engine from oil starvation.


" The secret of life is honesty and fair dealing...
If you can fake that you've got it made. "
Groucho Marx

 

Mine was reading between 5 and 10 psi at idle for a long time , one day at a stop light it shot up to over 60 and stayed there , I replaced the sending unit and now at idle it runs around 35 .

 

My oil pressure jumps all over the place, it has never got down to 5-10 psi though. Is the needle jumping around normal for these cars? It doesn't jump around constantly but it does range anywhere between 25-60 psi.

Where is the sending unit located? Do you think I need to change it and how hard is it to change?

 

I don't think that's true. As far as I know, the switch keeps the pump running as long as there is oil pressure, but it's only there in case the relay fails. If the relay is good low oil pressure won't kill the pump.

 

My sending unit is located right above the oil filter , apparently their notorious for being inaccurate and are prone to failure .

 

What he said may very much be the truth. You can purchase the sender thru most auto parts / racing catalogs as I did. In my case if the pressure drops below 20, a super bright light (simular to an autometer shift light) comes on and the pump shuts down. It's not a plug and play deal though. You have to wire it in that way.

 

Ya... He could have wired it this way, but the stock configuration is exactly how jv9999 stated.

 

Let's see here, are you saying the purpose of the switch is to protect the fuel pump relay from low oil pressure ???? If the relay fails, the pump shuts down regardless of oil pressure - high or low. The engine needs protection from low oil pressure ( in my case below 20 psi ) not a failed fuel pump relay - No?

" The secret of life is honesty and fair dealing...
if you can fake that,you've got it made. "
Groucho Marx

 

GM wasn't worried about your engine. They were worried about leaving you stranded if the FP relay failed. I realize it's odd, but that's the way they designed it.

 

+1.

I did my whole wiring harness. That is how it is from the factory, no question about it. The oil pressure switch is only there in case the relay fails.