I do not remembe who had replied back about my problem maxima but here is the compression readings
1 140 4 150
2 90 5 90
3 150 6 150

i was wondering why is the middle cylinders so low, possible valves out of adjustment or valves not seating. Or possibly bad rings. What can i do from here to tell if my rings or valves are out of adjustment or not seating. The car runs fine on the high way, but has alot of blow by through the dip stick and fill cap. I can see the steam and smoke come thru but it does not burn oil.

I appreciate to those who have tried to help and apprecciate those who reads these postings.

Thanks

Martin

P.s. What should i do next to diagnos my car?

 

Hi,

Why don't you do a wet compression test, putting a small bit of oil into the two bad cylinders and then doing a compression test on them. If the compression gets better then it's most likely your rings. This is just to help you narrow the possibilities. Good luck!

 

Also be sure you're doing all of the tests with the throttle wide open.
Those numbers look more like the ones I got with the throttle closed.

 

cosmos--

After you re-check the #2 and #5 cylinders and if you are still seeing bad numbers, then a cylinder leak down test will help you determine the cause of the weak cylinder(s). A leak down gauge can be purchased from an auto supply store, or you can visit your friendly mechanic.

By the way, when you re-check the low cylinders, make sure that you have cranked the engine enough to get a good reading. If you pulse the ignition and the piston has only gone through one compression cycle, you may see 90 psi, but after a few more cycles it should be pumped up to 150 or so.

You say you're getting a lot of "blow by through the dip stick and fill cap" so it could be bad compression rings if the low cylinder numbers are repeated. Be aware that the symptoms of a faulty PCV valve is poor idle and excessive pressure in the crankcase...

To do the leak down test, remove all the spark plugs, rotate the engine so that the cylinder to be tested is at top dead center and ready to fire. This is to make sure that the valves are closed. Install the leak down gauge in the spark plug hole and apply air pressure. The gauge will register the pressure drop indicating the percentage of leak. By listening to the exhaust pipe, air intake system and oil breather for escaping air you can figure out what's leaking, e.g. air out the exhaust pipe means an exhaust valve leak.
If you remove the radiator cap and see air bubbles in the coolant, you'll know you've got a blown head gasket or cracked head/block.

--SAM