Sputter

[HotZ28]

Originally Posted by Andrewhuffman

i did a pressure test on #4, #6, #1 cylinders, all read just above 60 psi in ark ideling. my uncle since the pressure is too low to just drive it until it completely dies.

I just realized that you have tested the compression while the engine was running! The “running compression” test is simply a test of cylinder breathing, not cylinder compression. Running compression at idle, should be 50-75 psi (about half of what the cranking compression should be).

When you do a static/normal compression test, you are checking cylinder sealing, not cylinder breathing. Check the compression again, using the normal (static/ cranking) compression test. This test would eliminate rings, valves, holes in pistons and that sort of things. A normal cylinder balance test is also helpful, so you know which, if any, cylinder is presenting a problem. (The engine should be warm when conducting this test).

To check “static/cranking” compression, all the spark plugs need to be removed. The ignition/module or coils are then disabled. The throttle should also held open. The engine is then cranked for a few seconds using a remote starter switch, or a helper, while the compression gauge is held in the spark plug hole. Note the maximum compression reading on that cylinder, then repeat the process, for each of the remaining cylinders.
As a general rule of thumb, most engines should have 140 to 160 lbs. of cranking compression with no more than 10% difference between any of the cylinders.

Low compression in one cylinder usually indicates a bad exhaust valve. Low compression in two adjacent cylinders typically means you have a blown head gasket. Low compression in all the cylinders, would tell you the rings and cylinders are worn and the engine needs to be overhauled.

[rhandwor]

I just use a pump oil can to put oil in. Also are you using a pressure tester which threads in with an o-ring. The ones you hold in have a tendency to leak.
When the valve cover is off look everything over. You probably need to take the engine out and have a machine shop get it ready for your rebuild.

[Smith1000]

Do you have to add coolant to it? Is the coolant disappearing?


Also, has the fuel filter been changed recently? Just asking because you said it has been running smoother and you could punch it and it would take off smooth, but would start sputtering after about a quarter mile. Sounds like it could be starving for fuel.

[Andrewhuffman]

hey, its fixed, i guess i broke a plug, and now it works great.

still i dont know how its fixed because ive already changed the plug.

also it still has 70PSI of compression in every cylinder. what could be the cause of this?

p.s. it runs juat as good as it did a week before it broke, so it might of always had 70PSI.

i know the gauge is right because it read 120 on a diffrent car.

[Bassasasin]

Originally Posted by Andrewhuffman

ive changed the EGR vlave, eventhought he old one was clean. my next attempt was going to be a higher octane.

WTF is a gas distrubitor?

A gas distributor well theres
.. SHELL, CITGO, Phillips66, TEXACO, BP, EXXON,
LOL.. I bet you dint think that.. heh.



SUPER on the fix... Of course we cant guess on something like that without inferring something,, however a cracked plug can really be a pain..

Honestly I did think of it.. heh

Proudly Drive, Live long and prosper.. lol

[HotZ28]

Well, congratulations on finding the “broken/dead plug”! I am still not convinced, you are following the proper procedure for checking compression. (See post 16). If you did do the “static” compression test and get only 70 psi on all cylinders, then your short block needs major work or replacing. I think this thread has served its purpose, so therefore, if you have any further problems, feel free to start a new thread.