What's going on, working on a 2003 2.3 dohc b2300

Started by checking hoses and cleaning iac because rough idle due to suspected vacuum leak. Removed intake manifold and doubled down on previous valve cover gasket job (performed with minimal instructor supervision during shop class) to double check work. Cleaned out oil in spark plug gap best I could (microfiber and carb cleaner) and used weatherstripping seal before setting valve cover gasket like Scotty Kilmer suggested in youtube video (https://youtu.be/LeH4h0aEmsI).

Also, i was curious about cylinder condition and removal process was started but had trouble with half exposed camshaft sprocket not budging for brand new 13mm open wrench. How do we remove cam sprockets not in the open? Can't get a socket in there. Looked all over youtube and only identical engine videos are for valve cover jobs (https://youtu.be/YvL5HnigopI). Would like to inspect cylinder condition and remove grime before performing compression tests after reassembly! Don't want to have to go back in after reassembly! First time on forum.

also prior to work idle was high. autozone scantool was throwing p0171 p2004 and p2195 codes. Recommended new o2 sensor but decided to bundle work on engine together. Possibly due to 3 or 4 missing vc bolts?? Tube between maf and vc being loose?

 

Welcome to the forum

Never tore down a Mazda L engine, aka 2.3l Duratec so can't help with that part

O2 sensors are the only sensors that have a mile/time limit, they have a chemical coating that reacts with air(oxygen) in the exhaust and that reaction generates a voltage, 0.1v to 0.9v
And they simply run out of the chemical coating after 100k miles or 12 years which ever comes first
And the bad thing is that as they get older they cost you Money, the voltage drops bit by bit so computer runs the engine RICHER than needed, so lower and lower MPG and that costs you money at the pump every time you fill up, its not drastic just a slow drain on your wallet, lol

 

Remove the crank pulley, you will either need a piston/flywheel stop or an impact.

It is ON there. Do not, under any circumstances, attempt to use the small hole/threaded boss in the timing cover to hold it in place. You will only break the timing cover.

There are no keyways or pins to hold the crank or the cam sprockets in place. The crank uses diamond encrusted washers, and you cannot lose them. If you do, they need to be replaced. There are 3, and if any one of them is not put back on, you will lose time, and bend valves. They are only on the crank. If there is no need to remove the sprocket from the cam, leave it on there.

You can release the timing chain without disassembling the front of the engine by removing the small bolt on the front of the timing case. From there, you will have access to the timing tensioner, which you can use a pick/screwdriver to release. Once released, you use a large plastic tipped wedge tool to push the tension side over, which gives enough room to remove the cam(s)

The bolt/plug I am referring to is shown here, its the small circular thing in between the idler pulley shaft and the crank snout seal, to the left. The tensioner is directly behind that.



More info and other things not mentioned can be found HERE