what the title says...

 

maybe an oil pump taking a dump....

 

Maybe the main/rod bearings taking a dump....


Maybe just the oil pressure sending unit taking a dump (very common.) If it's not making any knocking noises, replace this first.

 

Have you verified the pressure via mechanical gauge?

 

Nope... havent verified it..

Sending unit is about 6 days old.. previous one was 6 months old..

 

Might want to do that.

i've had a bad sending unit out of the box before. That sucked.

 

I had 3 in a row once. That's when I quit buying GP Sorensen parts.


If the pressure reads the same with the old and new senders, then they're probably accurate. The gauge itself may be going bad (3rd gen gauges are notorioulsy inaccurate) or you may have an actual problem. If the senders read the same I'd check it against a mechanical gauge, to verify the dash gauge's accuracy.

 

Mine was GP, too ...those darn blue and white boxes. Avoid GP.

 

No oil in the pan could cause pressure to be low..

Sorry, someone had to say it.

 

Nah theirs oil in the pan

Smartass...


The car will start with around 30-40 psi, after normal driving it drops to around 15-10......

 

Is this what the dash gauge says or is it the mechanically verified pressure?

 

10 - 15 at idle or at speed?

 

This is what the dash says, im going to assume that it is correct.


idle and speed. As i hi tthe throttle the oil pressure seems to slowly go up...

 

Hard to say the likely causes, not knowing much about your car...other than it has a fancy sig picture so it must be slow...

So...what mileage is on the engine, what brand and weight oil are you running, and what filter brand and part# are you running?

 

That was the main reason that I read this one first at lunch... I wanted to say it.

 

the question though I have is where is the pan?

you can have a full 5 qts of good quality synthetic oil in there and your not going to have much oil pressure if it is just sitting there on your shop floor


might be part of your problem

 

things though that can cause problems
leaks... they are decent at bleeding pressure

don't know if you guys have it but on my car there is a oil bypass for the when oil is cold it doesn't go through the e-shaft (crankshaft) to help with warming the motor up. when the bypass is open it has a low oil pressure. so just think if it sticks in bypass mode you get a constant low pressure


you can also have problmes if places where there are oil holes like the rods mains, piston and such have the clearance worn out

oil pump

blockage in the screen on the oil pump

so might want to check that stuff out

 

10 psi is within normal range at idle. General rule of thumb is at least 10 psi per every 1000 rpm.

The factory gauge is not at all accrurate. Always verify with a mechinal gauge before ripping into an engine for oil pressure problems. Again, there is no need to worry with 10 psi at idle.

 

I was amazed when i went on Mitchell on Demand the other day and saw taht oil pressure spec for my 89 TPI is 6psi @ 1000rpm!!!