Sputter

95 lesabre 3800 SI, drives smooth untill i press the gas down hard, the sputters to gain speen. at high speed it is either unnoticable or not sputtering. I'm thinking plugs and wires? any suggestion to test this theory or any other theories. ps, i went to the beach toay.:banghead:

Use an ohm meter to check your plug wires. They should be around the midpoint on the scale. The most important thing is some continunity through the wire. As you have the wire touching both ends wiggle the wire hunting a minute break.
Pull the plugs and check gap and for any small cracks or oil covered plug end.
This would be a good place to start.

My dad taught me this little trck to detremine if the wires are bad.

At night, make sure its dark, start the car and put it in drive, engauge the e-brake.

open the hood and press the throttle cables, adding stress to the engine will cause it to skip and thus i saw the spark jump out of the cable.

this is dangerous but sorta fun.:icon16::evillol:

On a token note, the same oculd be accomplished with a spray bottle of water and the same conditions, less the vehicle in drive. :2cents:

Bad news.... stipp skips on the 4th cylinder. i've replaced the plugs, wires, coil packs, ignition module, and cleaned the injectors. i'm going to get a compression test tomorrow to see if thats. could an o2 sensor or an EGR valve be the cause? the check engine light dosnt come on, so my obd1 puts out no codes, or so i think because i havent checked. anyone know anything i should check?:banghead::banghead::banghead::banghead:

After you replaced all of those things does it act up exactly the same as it did before when accelerating (skips, sputters when pressing hard on the gas) or is it just now missing on one cylinder (#4)? In other words, did the repairs change anything? How can you tell it is cylinder #4?

Might check to make sure all of the plug wires are on tight. I have one work loose now and then and there is a miss. Usually records though and can be picked up with the OBDII reader. Once, after changing the plug wires, I did not get one on tight and there was a miss on that cylinder.

Does it have good fuel pressure? Also, when was the fuel filter last changed? Maybe the filter is getting clogged and it is starving for fuel when pressing into it.

I would use a noid light and check for power to the injector. Then I would use a stethoscope and listen to the injector. Also ohm the injector. The ohm one next to it and compare values.

now ive changed the EGR valve, and o2 sensor. 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. he also has another engine i could swap. just wondering if its possible to fix this problem buy putting in new vlaves and gaskets. also how much would the total cost be in parts i need to fix this problem.

After you replaced all of those things does it act up exactly the same as it did before when accelerating (skips, sputters when pressing hard on the gas) or is it just now missing on one cylinder (#4)? In other words, did the repairs change anything? How can you tell it is cylinder #4?

Might check to make sure all of the plug wires are on tight. I have one work loose now and then and there is a miss. Usually records though and can be picked up with the OBDII reader. Once, after changing the plug wires, I did not get one on tight and there was a miss on that cylinder.

Does it have good fuel pressure? Also, when was the fuel filter last changed? Maybe the filter is getting clogged and it is starving for fuel when pressing into it.

before i replaced all those things, it would skip when i heavily accelarated. after changing it would skip no matter what. i deliverin that car and as the night went on, it started ideling smoothly and only skiping when i heavily accelrated.

today it ideled fine and drove smoothly, i even punched it and it took offf, not even a 1/4 mile after i did that, it started skipping. this would explain the compression i think.

Pull the spark plugs and pump some oil into the cylinders if the pressure comes right up you have worn rings. If the oil doesn't do any good you may have a leaking valve or worn valve spring. I would pull the valve cover and look for broken or worn springs.
Tell what you find and we will go from their.

Pull the spark plugs and pump some oil into the cylinders if the pressure comes right up you have worn rings. If the oil doesn't do any good you may have a leaking valve or worn valve spring. I would pull the valve cover and look for broken or worn springs.
Tell what you find and we will go from their.

how do i pump oil into the cylinders? do i just pour oil where the plug goes in? how much oil?

ive never seen a new, or worn valve, or spring, so i basically wont know what im looking for. any basic detail wouuld be helpful.:icon16:

WOW what a pain... sounds like EGR related like its not closing at higher RPM. ..

or gas... have you tried a different gas distributor or octane.

Or your harmonic balancer wheel has a flaw..

Geez... Im watching this one.

Good Luck.




..

WOW what a pain... sounds like EGR related like its not closing at higher RPM. ..

or gas... have you tried a different gas distributor or octane.

Or your harmonic balancer wheel has a flaw..

Geez... Im watching this one.

Good Luck.




..


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?

the harmonic balance was taken off about 4 months ago and i sorta bent it, but i bent it back so it might not be factory perfect.... how would this cause anything to lower the compression?

i did a pressure test on #4, #6, #1 cylinders, all read just above 60 psi in ark ideling.
I agree with your uncle, if you have only 60 psig on the cylinders you tested, and the compression test was done correctly, you have an internal engine problem and all the parts you are putting on the outside, are a total waste of time and money!

Another thing, if you had a bent or burnt valve, that would usually be confined to one or two cylinders, not all of them. If the cam lobes were worn out, you would also see a drop in compression, but usually, not on all of the cylinders! Check the compression on the other three cylinders! If all are that low, you must have blow-by like crazy! It would be better if you could find someone to do a leak-down test rather then the compression test. With a leak-down test, you can tell exactly where the cylinder is leaking. i.e. Valves, rings, head gaskets etc.

Pull the oil fill cap off and start the engine. Place your hand over the fill hole in the valve cover and see if it sucks in, or blows out. Remember, 60 psig is only 1/3 of what the compression should be! One more question, do you know if the engine was overheated?
WTF is a gas distrubitor?
A distributor is somebody who distributes something, in this case, someone who buys and sells gas. You don’t have one on your car!:grinno:

it hasnt over heated,not to my knowlage, it had very low mileage when i got it and only 2 previous owners and one wreck in the rear. but, i did notice a few months ago that the upper radiator hose was flat and worn out like it was sucking the hose flat.

it has no temp gauge and the light has NEVER came on, except for the start up so i know it works.

i replaced the thermastat and the hose, now its doing the same thing so i duno if it gets hot enough at idle for me to see the water circulate.... maybe i just get a lower temp thermastat?

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).:uhoh:

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.:uhoh:

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.

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.

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.

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

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.
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