First, thank you to anyone taking the time to help me. I've searched posts and tried some things, but now I need help about what to do next.
The problem: Low Oil Pressure, as measured at the stock oil pressure sender/sensor on the HPOP reservoir on the L front of the engine.
How bad it seems to be: I get a "no oil pressure" reading at idle, but my truck starts, runs, and seems to drive fine* (I don't know if I'd recognize reduced power since I've not owned a 7.3 before this one I just got).
-At about 900-1000 rpm on the factory tachometer, the dash oil pressure guage registers "on - good oil pressure"
What I think it means: My idle oil pressure is less than 5 psi, and at 900-1000 rpm it's >5 psi, assuming my sender is functioning properly.
What I've heard about it: Read this and other forums. Learned common causes for Low Oil pressure including: failed LPOP, cracked front cover face where it mates with the LPOP. Injector oil O-ring leaks. Failed/cracked/or blocked oil pickup tube, and of course Low Oil level in the pan!
What I've done about it:
1. Replaced the oil sender/sensor* (well, the previous owner did, said it didn't fix anything, so he left the wire disconnected)
2. Made a terminal and reattached the white wire/Red strip to the sender and got the dash reading I describe above.
3. Jumped right in and figured pulling the oil pump was next.
It and the front cover appeared OK to me, but a Melling 208 may/may not be an improvement, so I installed one. The truck has 115,000 and has been driven, towing frequently, for 15K in this low-oil-reading state with no apparent problems.
4.Got a few stitches in my hand (at the kitchen table courtesy of my wife) when the 10mm flare wrench broke loose one of the oil pump bolts and and I nailed the sharp flanged edge of the oil pan
What I'd like: Help!
I have a few questions, first of which is - is it possible that the reading taken at the stock location is inaccurate? Has anyone ever seen an oil galley blockage to that reservoir? The HPOP stays full and the truck seems to run fine, so I kinda doubt that..
What's the MOST likely cause of the low oil pressure? Replacing the LPOP didn't seem to fix it - oh well, at least that's narrowed down and I've got a new oil pump on there - my knuckle will be fine in a couple days - ha!
Seriously- what might folks suggest I try next?
I'm considering, in this order.
1. Put a mechanical guage in place of the sender to get quantitative PSI numbers.
2. Pull the oil pressure filter head, which I believe involves pulling the whole oil cooler assembly. In the head reside the excess pressure bypass valve, and the oil pressure regulator valve proper. Clean and inspect for stuck regulator or missing bypass valve parts, plugged oil cooler?
3.Do the "pickup tube test" - over fill crankcase (How much extra oil?) jack up the rear of the truck, and see if Oil pressure improves. I understand this immerses the pickuptube er, "to the hilt
" and thus confirms a cracked or broken pickup tube, but wouldn't help to diagnose a plugged/blocked tube/screen.
4.Kinda get frustrated about the internal oil leaks that could be going on, and wonder how hard and expensive it might be to find and fix.
5.Seriously think about giving up.
6.Seriously think about driving it until it blows up and put in another used 7.3