PROBLEM 1:

Looking for any advice here. I obtained a 98 4runner 3.4 donor vehicle with front end damage. It still ran and i drove it into my garage with no problems to yank out the engine. For the swap the only thing I replaced on the 3.4 was valve cover gaskets, timing belt and water pump. I then swapped my 3.0 oil pan and 3.0 pick up tube. I cut off the extra leg of the pick up tube that was not needed, installed a brand new gasket on the pickup tube and slapped it all back together. After getting no oil pressure on start up, I confirmed my gauge was good, went through 3 electric gauges then finally hooked up a mechanical gauge....Turns out I have ZERO oil pressure!!!! When it fires up it sounds good. I've only ran it for about 10 seconds or so each time because of this oil problem....I can't think of anything i did that would cause no oil pressure. Sounds like reusing the 3.0 pickup tube is a common thing and it fit like a glove. yes 5.2 ish quarts of oil are in engine.

Is it possible that i need to pack the oil pump with petroleum jelly so the pump is primed???

PROBLEM 2:

I'm using an Offroad Solutions conversion harness. When i turn the key to crank the engine the power dims as if juice is being pulled from the battery but the starter does nothing. If i keep the key in the on position and jump the starter exciter (solenoid) wire if cranks and fires up. When i hook a meter up to the exciter wire from the ORS harness I get about 11.6 volts when turning the key. When i hook the exciter wire back up and turn the key nothing happens... Why isn't 11.6 volts good enough to make the starter solenoid activate??

Thanks

 

Well I pulled off the oil filter and oil came out so it looks like oil is moving.... I fired it up and let it run for about 8 minutes. never got any pressure from the mechanical gauge. I later fired it up again this time reving it up a bit with the gauge disconnected to allow the pressure to escape. with it revving I finally got oil to start moving through the plastic mechanical gauge line. But at idle the oil pressure drops back down and doesn't even register on the mechanical gauge. I've seen some threads talk about how the 3.4 has low oil pressure at idle but not registering on the mechanical gauge is crazy.... This motor has 206K miles but seems to run fine otherwise. There is no knocking or unusual noises at all.

 

So my oil pressure is low at idle but still most definitely registers about 1/4 the way up on the factory toyota gauge that came with my 3vz truck. At speed it's halfway or higher on the gauge. I would be wary of driving it and try to diagnose what might be causing the low pressure before driving it too much, could be as simple as an issue with the pan/pickup.

Have you reached out to ORS about the harness? They should be able to give you some troubleshooting steps. Thinking maybe your starter solenoid might be on its way out which is why it doesn't work with the 12v signal but you can jump it.

Goodluck!

 

Put a mechanical gauge on it and I have zero oil pressure. If I rev it up i could see the oil start climbing super slow through the gauge tubing but when you let off it falls back down. Even tried cracking open the tube to gauge connection to make sure there was no air pressure. I can't think of anything I did that would effect this. Yes I am using the 3.0 oil pan and pickup tube on the 3.4. I had to cut one of the braces off the 3.0 pick up tube and then it fits perfectly. I have a new gasket from toyota for the pickup tube. From all my searches this setup should work. I removed the plugged port just below the oil sending unit and cranked over the engine and got no oil flow.

Since I have a 4" suspension lift I think I can get the pan off without pulling the motor. I'll start there to inspect the pickup tube. But I guess I will be changing out the oil pump. Which totally sucks because you have to pull off the whole front of the engine. And after searching everywhere I don't see anyone talking about how these pumps go bad. Some may experience low pressure, but i can't find anyone talking about zero pressure or a complete oil pump failure.

As for the wiring. ORS has been helping but I think the biggest problem is the poor Toyota design as explained here:

https://www.yotatech.com/forums/f116.../#post52422426

 

The only question I have is what was the range of the gauge you used? The reason I ask is that a high pressure gauge will read zero, when a low pressure gauge may read only a few pounds.
Additionally, (although not entirely necessary) it is better to cutout the baffle to allow the oil pickup to mount properly, than to cut the pickup mount.

 

you have to use the oil pressure sending unit from the vehicle not the engine. the conversion harness has nothing to do with the starter. verify the wire from the sending unit is connected to the oil pressure gauge.