My wife bought the car used almost ten years ago; though i hate the lowering and slightly noisy exhaust the previous owner did to the car, it used to be smooth running with good acceleration.

At some point over the years it became an automatic massager, with everything inside vibrating when running (If there are any other folks out there that have a few years on them, remember the "Magic Fingers" vibrating beds that were in some of the motels, that you would put a quarter in and the bed wold shake? That is what it feels like!). I replaced all of the engine mounts except the one that is buried on the right (passenger) side about center, as i have no idea as to how to get at it other than taking the dang engine out.

Is it reasonable that this one mount could be the source of all of the vibration given that the others were replaced? I have no doubt it is bad in that the others were. If it is a strong possibility, can anyone provide a link as to just how one can get at replacing that thing?

The vibrations over time have added to the noise of the modified exhaust in that i am fairly certain some pipe fittings have been shaken loose and i will be going after them also, but for now, i just want to find out if there is a way to go after the vibration-

Thank-you for your consideration and thoughts!

 

Did the vibrations begin after you began replacing the other engine mounts?

Refer to the FSM in the in the forum index sticky for your year / model, engine mount replacement & follow to attain the alignment measurements called out there.

Its not clear if the vibrations your feeling is wheel alignment, wheel balance, engine mounts, or some combination there-of. Let us know how it goes

 

Hi again! Are we the only people in this forum???

I replaced the engine mounts (those which i could) in response to the vibrations, which are constant, whether moving or sitting in idle. I would have thought handling three out of four (if i recall; it was a couple years ago. I think there were an upper and lower on the right - with the center being the omitted - and one on the left) would have had significant effect, but perhaps that omitted troublesome one that i could not get to is critical. Just start the engine up and everything rattles!

 

Ok good feedback, so the vibrations are from the engine & were there before the other engine mounts were replaced.
Have you performed a compression test, or cylinder balance test to see if they can shed some light on the situation? My old Actron CP9145 scan tool can perform a cylinder balance test, so if you have, or can borrow one, do that as it's easier & quicker than the compression test & tell us if it flags a cylinder.

 

Hmmmmm. I think i'll first look up "cylinder balance test" and then i will see if i can scrounge one up!

Thank-You!

Edit: OK! Will get on the balance test "old school", but this might have to wait, i "get to" sit on a plane for about 9 hours to LA tomorrow morning and get beck here on Saturday- Big fun.

 

I've done the LAX thing many times, so don't envy your trip at all!!! On second thought, its a holiday week, so business folks will be heading Out of LAX, not into it, so you might have it easier that I first thought.

On the cylinder balance test, the scan tool monitors engine rpm, then disables a cylinders fuel injector & measures rpm drop, so cycles through all the cyls to see if one drops less & if so it's the one to perform more checks on, like maybe its compression is down so isn't making as much power as it should. Anyway it only takes 5-6 min to run on a 6 cyl engine, less for a 4banger, way faster than we can perform a compression test & all we have to do is sit in the drivers seat with the tool plugged into the DLC & toggle through a menu & follow instructions without falling asleep!!!! Its a fast way to find a problem cylinder for further diagnosis.

 

LAX was worse than ever, with major construction going on throughout, though the earthquake added a certain something to the visit.

As to the Neon, i now need to get it in for a proper cylinder balance test. The "old school" method only resulted in two pieces of information:

1. Each time i removed a wire the RPMs notably dropped, and
2. I can still get a nasty jolt (several, in fact) from getting in the way of the current flow...

 

On the cyl balance test, if you don't have, can't borrow, or come by a scan tool like the Actron CP9145, or the like, that can perform a cyl balance test, you might try a "poor mans" balance test by disconnecting the fuel injectors electrical connectors, one at a time as the engine is at warm idle & monitor the engine RPM drop, for say 4-5 seconds, on each cyl, to see if one cyl drops Less than the others. As that would indicate its compression belongs on the suspect list for a valve seating, or stuck, or worn compression piston ring/s problem.

Then you could go to that cyl & perform a cold & warm compression test & if low on compression maybe a squirt or two of oil in the cylinder & cranking it over slowly once ot twice to spread the oil & repeat the compression test.

If compression improves with oil in the cylinder, maybe suspect ring land gum, or varnish, or carbon deposits, causing the rings to stick. Then maybe try a over night, or over the week end piston ring soak with say 2 or 3 table spoons of Marvel Oil in the suspect cylinder. Screw the spark plug in a couple of turns so nothing falls in & so the Marvel Oil solvents don't evaporate on the Warm engine & let er soak, the longer the better.

Then to prevent hydro-locking the engine, disable the fuel pump so the fuel injectors won't wash the cyls down & remove the spark plug & let the starter crank the engine over a couple of times to blow out any excess Marvel Oil remaining. Then repeat your compression test on that cyl & let us know what you find.

More thoughts for consideration, let us know what you find.