vibration at idle

[romulous]

Hi to everyone,

I'm glad i found this forum, I 'm new to this kind of car stuff and i bought my first car last year (kia pride lx 94 model). Here it is my mechanic told me that the transmission mounts of my car has cracked and need to be replace, so i bought new transmission mount and replaced the old ones. I noticed that since the replacement of the transmission mounts my car vibrates during idle specially when my A/C is on. Could somebody tell me if there is someting to do with the transmission mount? And I'm guessing that the rubber of the replacement that we installed is hard. Is there a work around to soften the rubber of the new transmission mount?

thanks in advance and regards

[FestYboy]

you don't want to soften your mounts, the added movement will fatigue them and cause premature failure. more than likely what has happened is that since you've changed the mounts, you can now feel a vibration that was already there. more than likely, it's a misfire (low RPM, high load). when was the last time you had your engine serviced? plugs, wires, cap&rotor, injector service, fuel and air filters? have you ever had the engine flushed? you very likely have high carbon deposits everywhere causing little problems everywhere, and all those little problems are causing one big problem.

i have 2 words for you (and everyone else on this forum): REGULAR MAINTENANCE

... solves 90% of the problems people have with their cars, except that they're too cheap to do it in the first place.

this is NOT me jumping down your throat, i'm just ranting 'cause i'm a tech and i see it every day ... cheap people suck...

[freshtiva]

All my festy have a little more vibration when the A/C in on.

[romulous]

My car is carburator and was top over hauled last 2 months ago they changed the oil seals and head gasket.I haven't changed the distributor rotor or any wires and I assumed that my engine is now on top condition. The idle speed is on 800 to 850 RPM. Well I'll ask my mechanic to check those wires, distributor etc. to see if it will improve the vib. Thanks for replies. Best regards to all

[FestYboy]

also have him verify the cam timing just for giggles

[ectonine]

"Engine flushes" are a wasted of time. The only way to get carbon off the pistons is to take them out of the block, or take the head off and clean them. I have done several "engine flushes", and broken the engines down right after to disprove this idea.

[kzbill]

Maintenace is for "cheap" people. it keeps "expensive" stuff from happening.

[FestYboy]

^^^^

HAHAHA that's messed up...

"Engine flushes" are a wasted of time. The only way to get carbon off the pistons is to take them out of the block, or take the head off and clean them. I have done several "engine flushes", and broken the engines down right after to disprove this idea.

BTW, flushes aren't for cleaning the tops of pistons, it's for everywhere oil flows (bearings, oil galleys, lifter valleys, etc.) and they DO work. for cleaning the tops of pistons, you need steam. run the engine to opperating temp, and gently spray a MIST of water into the throtle body while running. it takes a bit of time but you'll see the carbon being released through the tailpipe emissions.

if you aren't careful about this procedure, you can hydrolock the engine (this is bad).

[jglutz]

Need a better discription of rough idle. Hunting? Almost stalling? Starts well? Accelerates well, deceelerates well? warms up well? or just vabrates? It pretty easy to eliminate mounts as the problem. Reason I ask, the ECU uses the Mass Air Flow (MAF) sensor to set the fuel injectors. If the ECU sees a rough input, the fuel injectors respond incorrectly causing the MAF sesor to be more rough. Depedin on the make and model not a hard test to determine. Try the Ford vacuum test.

[elcamino1]

^^I agree wtih Festyboy about removing carbon deposits,also being from the old school,back in the day we would pour a small amount of water down the throat of the carburetor with engine running at a high Idle.If you've pulled apart a engine thats had a blown headgasket for awhile that piston or pistons always clean as new.
As for cleaning inside of engine flushes do work, but it helps if yours is very dirty to drop the oil pan to remove heavy buildup of sludge.

[jglutz]

Decarb...i dont know....what would have a carb build up that could prevent the engine from running normally. Oil sludge build up...not good...best way to flush an engine....warm it up...drain the oil....add 2 qts oil 2 qts kerosene... run five minutes max....drain....repeat 2/2......drain....add 3 qts oil 1 qt keroseene. Repeat if necessary....you won't believe the crud that will come out. I usally use cheapl oil when mixed with the kero. Also frequent oil changes (1k) will also aide in breaking down sludge. Make sure the filter is also changed regulary. Most oils today prevent sludge build up.

[kzbill]

I used to hear about diesel fuel and oil, an I know I have tried mineral spirits, but I think the best I heard is auto trans fluid and oil.
all have there own risk.

[FB71]

please permit me to clear up a few misconceptions about engine flushing. Modern engine oils contain more detergents than trans fluid, mineral spirits do not work well as a detergent. Solvent, yes. Detergents remove sludge and deposits, solvents remove lubrication. Kero/diesel also act a solvents, and can be rather dangerous to use. Your best bet is to add some naptha based detergents to the oil, found in products like Seafoam. That's for lube system.

For the combustion chamber side, I agree with FestYboy about steam. That's the most effective method for removing carbon deposits. Now, here's the way I've done it for 20 years, always with great success (proven by both a borescope and engine teardown). Three quarts of hot water in a gallon jug, to which you add a quart of trans fluid. The water is for steam generation, hot to mix with the trans fluid easier, and the trans fluid to lubricate the cylinder walls and reduce the chance of cylinder wash-down. Shake well till it looks like a strawberry milkshake. Find a SMALL vacuum line (1/8inch dia or so). Bring the engine up to operating temp, block the throttle open to maintain about 2500-3000rpm, and stick the vac line in jug. It takes a good bit of time (5 min or so) to suck down the gallon, but it will leave the inside of the combustion chambers nearly shiny clean.

[jglutz]

Kerosene....Deisel Fuel...Jet Fuel....Home Hesting Oil....Are all the same except for a few additives.

ATF compare to engine oil...ATF is the best commercially available lube...hydraulic oil...cutting oil there is. However, it.s not formulated to handle combustion gases.

The water and ATF does work..no doubt seen it. another vacuum injection I've seen work used Liquid Wrench.

My Previous recipe (oil and kero) was for the internal engine excluding the combustion chamber.

But fora commercial engine flush....I still don,t understand the point...I don't disagree that they can clean the combustion chamber...but what's the need? If the rings, valves, ERG, PCV are operating properly, whats the point. If they are not operating properly, the contamination will come right back. Or maybe i should ask...what problem could an engine flusf take care of that won't come back?

One risk of a quick break down in the combustion chamber is the scale that brakes down will get caught in the exhaust valve seat. Most of the pitting seen in an exhaust valve seat is the result of the scale being peeded in.