I got a 3.4 99 4runner auto thats swapped into a 94 pickup.

I swapped over the 3.0 oil pressure sender and have had it wired up for almost 2 years. I recently drove both of my dads 3.4 t100s and noticed that his oil pressure drops low at idle (like mine does) but at 55 or 70mph its near half the gauge, (mine barely gets above 1/4). Ive had some other wiring issues with my solder joints for the volt gauge and the speedometer (neither one works currently). Before i tear into my dash and try and find out if the sensor is off or if my soldering is bad, id like to find out what my engine with near 200,000 miles is actually putting out oil pressure wise to be sure.

I run pennzoil conventional 5w30 with a quart of lucas year round. (My dads 3.4s have over 250,000 miles each and thats the oil combo he is running and has had absolutely no issues in 15 years so im sticking with it.) I use a purolator gold color filter. My oil is always clean and free of grit and i have zero ticks or clicks or knocks coming from the engine. I change it every 3000 miles or so (no speedo or odometer so i cant be perfect)

I know that at idle once warmed up therea only like 5 psi of oil pressure. What psi should there be at different rpms? Like 3000 rpm or whatever. Under no load of course.

Thanks Travis.

 

Put a manual gauge on and be done.

That is all I run

What does your gauge read on start up after sitting for a few hours.

In your case it could be a bad sending unit diaphragm gets a slight leak allowing oil to get behind it. Reading lower .

I had this happen more then a few times.

Then it could be your engine is starting to wear

around 2000 rpm I run around 40 psi

 

Here you go...36-75 psi@3000 rpm at operating temp.

 

Oh wow big gap. And yeah i am doing a custom cluster soon but i dont want an oil line running into the truck unless i have to. I also didnt know how high of an oil pressure gauge id need.

 

are the rpms the same at that speed? what year are the t-100's ? the oil pressure gauges don't read perfectly in the older pickups.

 

the rpms arent the exact same but close. id just like to know at 3000 rpms which is 70ish in my 94 pickup and prolly the same in the t100s. 55mph is like 2500ish rpm in my truck and close to that in the t100s. the t100s are 95 and 98. the engine i have is a 99 so they should be close to the 98.