Best way to prime engine after sitting 3+ years.

I will be starting my 02 3.4L V6 140K miles after more than 3 years not being started. I did mainly maintenance like timing belt/water pump. Bunch of hoses replaced and suspension work. So many projects and some life challenges has delayed the rebuild for some time. I have new engine oil/filter and new coolant in it now. Put in a new radiator and air filter as well. I dropped the tank, drained out the old gas and replaced the fuel pump and sock filter as well as inline gas filter. Because the engine has sat so long and the engine oil is minimal on the engine internals, before start up I plan on pulling out the spark plugs and dropping some oil into the cylinders for some lubrication upon first start. And possibly pulling the fuel pump relay to get the motor rotating before it fires. Looking for some guidance if I am going in the right direction and open to other things I could do before starting the engine.

 

pull the plugs crank it for 30 seconds. put it back together and let er rip these engines dont require much lubrication on the top end to be happy. the bottom end gets oil quick. you should be fine.

 

Pull the EFI fuse too.

 

I say just start it. It can't be any worse than when they first started it at the factory.

Unless you've flushed the internals with cleaner, it's got oil.

 

It likely is fine (I mean… I know guys that don’t prime fresh rebuilds on Japanese cars.) but it’s just good practice to at least build some kind of pressure

 

Update on the engine start. I removed each spark plug and squirted in some Marvel Mystery Oil with a long skinny hose and syringe into each cylinder. I wanted to be on the safe side. Then removed the EFI fuse in the engine bay fuse box and cranked the motor 3 to 4 times. Then put the fuse back in and started it again with it sputtering the first try and then fired right up the second start. It is running really smooth with no issues after all the work put in. It idles a little high still even after its at full operating temperature. I adjusted the throttle cable and cleaned the maf sensor but that hasn't brought it down to the 750 rpm i want. It sits around 1100 rpm right now.

 

I'd complete a drive cycle as described in the workshop manual to set all of the readiness monitors before I worried about the idle too much at this point. If everything sets to ready and the check engine light doesn’t come on, I’d worry about it then, if it still has a high idle. The ECM’s adaptive memory is blank at this point in your repair. It has to learn the fuel trims and everything, I would expect that the idle being high is normal until the ECM has learned all its adaptive’s. Drive it!

 

This is correct. It’s going to idle weird and drive weird till the ECU relearns the drive cycle.

 

This.

But if after the drive cycle it's still idling high, clean the IAC. Make sure you remove the part with the two screws covered with fipg, and clean that as well.

 

Nice, glad the truck has an owner that gives a shit.

When I was apprentice we started a race mustang from the 60's that had been sitting for 12 years. We didnt even check the oil level, I got in a lot of shit.

 

This makes sense thanks, I didn't think about that. Getting a few things buttoned up and then I will run it in to work a few times on the freeway and go from there.

 

Interestingly enough, even though its not a Tacoma, I was just working on a truck that the customer had disassembled three years ago. It was a Ford 5.4 3V. For him what started out as a cam phaser job ended up being a head gasket job because the spark plugs came apart, like all the other 5.4 3V engines do. He wasn't using the best removal tool, and ended up having to pull the heads. Three years pass, and he gets up with me because he basically can't remember where everything went ( after getting it 80% put back together). He learned a lot on "YouTube University" and actually got some really good information, and had the long block together when it came to me. He replaced what he needed to with the correct items thanks to YouTube. One of those items was a high volume oil pump, that was installed three years ago, and never got primed with oil. I went to start the engine, and like yourself I wanted to get oil flowing through the engine before it started on its own. These trucks have a dummy gauge, its an oil pressure gauge that might as well be a light, Fords are bad for this, and they set the gauge up so that it would not fluctuate with oil pressure up and down at different temperatures. So even though it looks like a gauge, it will go to half scale and stay there at about 5 psi and above, just like a light would turn off. I left the crankshaft position sensor unplugged and spun the engine over....and over....and over, no oil pressure. I then plugged the crank sensor in, and tried it again. It still wouldn't start, or build oil pressure, he had left the crankshaft position trigger ring out of the timing cover. I then decided to retrace basically everything that he had done, including timing the engine. Upon inspection the oil pump was dry as a bone....after I ran the battery down twice trying to get the oil pressure to build, there were no signs of it sucking air in the pickup tube or anything. After packing the oil pump gears with transmission assembly lube, I reinstalled everything and gave it another shot. Crank sensor unplugged, spun the engine and the oil pressure came up quickly. I then started the engine, just to find out that it was knocking. After talking with the customer, we came to the conclusion that it was making the exact same noise that it was before he touched it three years ago..... Knock at idle, going away when the engine revs, just like a cam phaser, only ten times louder. He didn't know that though. After some more digging, I found the flex plate broken, which was his original knocking sound.
I still don't have a clue as to why it wouldn't build oil pressure to begin with unless the small air gaps in the oil pump didn't allow it to get primed correctly, because it was completely dry. I've always disabled the engine in some form to get it primed with oil before starting it, no matter what emblem is on the grille.
Here’s what the flex plate looked like. A little exaggerated as it was lined up on the vehicle, just cracked.

 

A dry oil pump will not prime itself very easily, that's why service info generally tells you to prime it with oil or assembly lube before installing.