Proper timing mark position needed?

Do you need the instructions on setting the timing, or just the ignition timing spec for the crank pulley? The spec with a timing light is 3-7 degrees BTDC @ idle. The timing mark on the crank pulley should show 15-5-0 for degrees on the timing cover and then the notch on the crank pulley needs to at the posted spec *Note with certain pins jumped out at the Data Link Connector (which I'll post a picture of).

This is the spec and the pins to jump out to set Base Timing, once the timing is set, you can shut the engine off, remove the jumped pins, and the timing should advance by the ECM to the spec on the 5th diagram. 4-17* BTDC.

This engine is listed as an interference engine. Meaning if the timing chain jumps, breaks, or the camshaft sprocket broke off while the engine was running, then what happens is the pistons hit the intake or exhaust valves and bend them. I would pull the valve cover off first and check for damage, Ill post the service info on this still though for you,
It's listed as a "1998 Toyota Truck Tacoma Regular Cab 2WD
L4-2438cc 2.4L DOHC MFI".
But there are 2 timing chains in service info here. One in front of the other, the front one is for the camshafts.
This is also very old service information as well.
The 13th and 14th diagrams are for the oil pan and list the oil pan installation before removing the old gasket material, so take that into note.
But if you pull the valve cover off and remove the camshaft, you might find that some of the valves don't look right if they were hit by the pistons when the cam sprocket broke off. If the valves are bent, the cylinder head has to come off to replace the valves and whatever else might have been damaged.
With the camshaft out, all the valves for each cylinder should be closed, so there should be no cylinder leakage if you do a cylinder leak down test, by putting compressed air into each cylinder to check for leaking valves, so you're not doing a compression test, just seeing if any air leaks by the valves, if they are bent, they will leak into the intake or out the exhaust. A search said this was an interference engine, but service info have any tests like that.

But this is all the timing chain install information, and marks, but check for cylinder leakage before you go through all the time of pulling the engine apart.

Okay, I found some other diagrams, look at the last 2 diagrams first. They show how these dual overhead camshaft engine is set up, both cams are driven off of 2 gears meshed together with timing marks on the back on each cam gear and then 1 timing chain, so this is going to be a very difficult repair, you might want to look into finding a used engine instead.
You may drain the oil and find metal particles in the oil, and the engine is no good if that's the case.

Okay, when you take the valve cover off, let us know what the damage is. I'm wondering if one of the cam bearings seized up or something along those lines, it would take quite a bit of force to break the cam sprocket right off.