Doing compression test on tacoma

Hello ima be doing a compression test on my 96 Tacoma 4x4 2.7l auto. What kind of compression could I be looking for? And I was told that I need to take the fuse out for the fuel pump to do the test can anymore confirm?

 

Myself I disconnect the ECM ground .This is just easier for me.

Nothing worse then the engine starting when doing a compression test.

The range of compression should be between 178 to 127 PSI engine warmed up throttle body wide open.

I crank between 5 and 7 compression strokes I tend to lose count

 

If I do get 125 Is that really bad?

 

Not to the point of total panic. But maybe time to think of your options buy an engine to rebuild lower mileage engine swap.

If time is not a factor think of rebuilding what you have.

At that point squirt a few drops of oil in the cylinder and see if the numbers come up if they do the rings are worn .

Better to have 4 cylinders close in readings then numbers all over the place

I had a 22R engine I could turn over with my hand on the crank pulley with the plugs in I drove for years .

It comes down to when performance degrades to a point you no longer find acceptable .

 

Just out of curiosity, why you checking your compression? How many miles on the engine, do you know history, etc?

Have the valves ever been adjusted? My understanding from others on this thread the 2.7 commonly gets tight exhaust valves, so if you get any low readings, you may just have exhaust valve(s) not closing completely.

 

325k but had a rebuilt and the owner before wasnt sure on it so I did it anyways came out that the cylinders were in the 180s all with in spec