Low oil pressure but engine runs great

[Ricko1966]

That switch being bad would not cause an extended crank. What that switch does is takes over if you lose your normal fuel pump power. Then if it is,say your fuel pump relay is bad that switch will close when you have oil pressure. It is a back up
In case you lose fuel pump power. That's why it causes the extended crank, if your relay isn't working you have to crank until you have oil pressure,which closes the switch and provides an alternate power supply.

 

[bucket]

That switch being bad would not cause an extended crank. What that switch does is takes over of you lose your normal fuel pump power. Then if it is,say your fuel pump relay is bad that switch will close if you oil pressure as a backup.

That's what causes the long crank. If the pump relay doesn't make contact, the fuel pump won't run until the oil pressure reaches 9-11 psi or so.

 

[Ricko1966]

Yea,went back and reread my post between typos and spell check it looked like a drunk wrote it,it's fixed now. I was trying to make things clearer for @geocrasher I hope the last 2 posts help.

 

[Rusty Nail]

Are you  certain the correct sender is installed? Worth looking into.
There is more than one possibility.

Yeahhh .. I thought the "pre metric" sender reads different than the metric sender but they will interchange in the block.
Much like the difference between the "amps" and "volts" gage... Im not yankin your chain.
Parts stores are likely gonna shelve the latter, it's EASY to get the wrong one.

 

[DoubleDingo]

Not related to the OP's original post, and I see he figure it out.

In high school an underclassman got a hopped-up '69 El Camino. Nice car, ran very strong, and never had any engine problems, but. Having rebuilt my 350 for my '56 and having a solid 60 psi cold and 40 psi hot, when I saw his oil gauge reading 10-15 psi whether idling or revving, I asked him if his pump was bad. He told me having high oil pressure on a high performance engine was not a good thing. I nodded in agreement, but never agreed with that. I want some pressure in the engine to keep things properly lubed.

 

[Ricko1966]

Rule of thumb for oil pressure is 10psi per thousand rpm. Lots more than that isn't necessarily good either.

 

[Johninbc]

Geocrasher, just he aware that modern gasoline turns the little rubber hose of the in tank fuel pump to jello. This can cause an internal tank return path allowing both backflow of the feed line and reduced feed pressure. The TBI pump is only 13 psi. The intake screen also turns to jello. That was the cause of my crank time. Pump itself can still be good.

 

[79dentside]

I have the same issue. My guage shows 7 psi and barely moves. I hooked a manual guage up and instead of 7, it read 52 psi. The guages are not always accurate.