2000 mustang Major Vibration 3.8l
 

Need Help!!!!! major vibration from idle and up. There is no miss, no noise, runs fine if you can stand to be in it. Vibrations so bad that it just broke the pass exhaust manifold. History: Vibration started then the clutch went out a few weeks later. I put in a new clutch kit, problem still exist. Vibration does not change with clucth in or out, so problem is in engine assem. Could the Harmonic balancer, flywheel(for standard trans) cause this? I have been a certified tech for 22yrs and never seen this. I cant run eng without balancer, no timing marks to align too see if it slipped. I have never seen weights on a flywheel, i dont know how that could go bad. If anyone has ANY info i would be grateful!

NOTE: CAR HAS ONLY 54,000 MILES ON IT, NO CK ENGINE LIGHT



Thanks

No check engine light? O.o

Major vibration? Not like the vibration you get from it idling too low? Do you have any more info at all?

Don't know if the 3.8 is neutral balanced but check the flywheel if the weight came off. Harmonic balancer is another place to check. So are the engine/tranny mounts. I also don't know if the 3.8 has a balancing shaft but if it does, you may want to check to see it isn't broken or disconnected from the crank. Does it also happen when the car is sitting still? If not, check the driveshaft and wheels to see if they are balanced.

balancer
 

Take the balancer off and sheck it out. Something seems very fishy here. I don't see how it could vibrate THAT bad and still run good.

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balance shaft
 

Rear wheel drive 3.8's don't have a balance shaft, only FWD.

wow no light, no codes.. differential?

Vibration 2000 3.8l
 

Thanks guys for offering to help! Anyway no low idle, no ck engine,runs totally normal other than a major vibration which started in early Dec and then at end of Dec the clutch blew up. I pulled the balancer yestergay and verified that the timing marks are inline with the keyway...so it should be ok. Does anyone know if there are weights on a standard flywheel or are there hoels drilled out for balance? This engine has NO balance shaft, i confirmed it with local rebuilders and both my Mitchell on Demand and Alldata. The oil is full and super clean. If it stacked a bearing it wouldnt have last this long.

Cant run the vehicle without the balancer due to crank sensor,and cant start the car without the flywheel, isnt that nice!

No only in engine, doesnt matter whether its sitting idling or driving its the the same...bad. Pushing clutch in does nothing to stop it.

Sort of sounds like an engine mount. But that'd make it worse during acceleration...so I don't know. I'll do some thinking and get back to you.

how would an engine mount hurt acceleration? engine he said is running fine..

An engine mount being broken would cause shaking to increase at higher rpms cause the motor would move back and forth faster at higher rpms then lower rpms... if it were an engine mount

Exactly. I can see how I confused you Stephen, I wasn't very clear. Vibrations would increase during acceleration because of shaking of the engine. If you have no idea what I'm talking about, walk out to your car and turn it on, open the hood and play with the throttle. You'll notice that the engine cranks back under acceleration....that is what I'm talking about. You throw that in with the normal vibrations from driving on everyday roads and you'll notice it quite a bit with a broken engine mount.

Harmonic balancer

Just because the marks are OK and the keyway is OK doesn't mean the balancer is OK. My bet would be either that needs replacing, the engine mounts are gone, or if the engine is external balanced, the weight on the flywheel fell off or the flywheel wasn't put back on correctly.

how would the balancer fail? its all there, no missing rubber, when they fail they either come apart or slip. this has done neither. i matched a new one with the old one and its the same. plus i have run 100's of cars without a balancer and they dont vibrate like this. Most engines are externally balanced, few are internally balanced. The engine mounts arent broken ,theres no lift. Its starting to sound like something nobody has seen before.

Thanks Guys I appreciate your time.

First off, you never run an engine w/o a balancer, that's just asking for problems. Secondly, almost all engines now are internally balanced, w/ some exceptions. There's a reason why external was called Detroit balanced. Now, the mounts can look OK and still be shot. In fact, this happened to me last summer where my mounts looked fine but was allowing enough motion so that the headers would bang against the body. Replaced them and problem solved. Now, there's only so many things that will cause an engine to vibrate crazy. One is the balancer, another is if the flywheel's weight fell off or the flywheel wasn't put back on in the right place (if external balanced), mounts are going, incorrect firing order (which is unlikely unless you just changed the plugs), rotating assembly is not balanced (which is also unlikely), or clutch assembly isn't balanced (which could be the case) or something came loose. If something else is going to cause it, it will most likely trip a code.

THANKS FOR ALL THAT REPLIED!
The vibration is GONE! I thought i would pass on this bit of info to you guys. We pulled the trans and the flywheel, which was just fine.... CANNOT fail the weight is cast into it. So the next day right before ordering a used complete engine, we decided to pick up a new balancer..put it on and WOW! its fixed. The harmoninc balancer WILL cause a major vibration! I been a tech for 22 yrs and never once had a single engine that would vibrate from a bad balancer. They come in with balancers missiing, broken, spun and never a vibration but this 3.8l will vibrate to hell with it spun just 1.5 inch from original spot. Note there was no physical damage whatsoever!!! Luck too all
Thanks Again,
Phil
Dallas,tx.
P.S. GO COWBOYS!...MAYBE

hmmmmmmm........
 

that happened to me, the wheels needed balancing, the dumbasses at Sears didnt do it right, took it to a small tire shop and had them rebalance, he said one had too much weight. I think they did it on purpose those bastards. Anyway mine would shake the shit out of the whole car only on the freeway though, took a while to diagnose it. Worth a shot i guess.

Major Engine Vibration
 

I ended up replacing the Harmonic Balancer on my '99 3.8 - It cost me $123.00 from the dealer since it has the pulley attached - it solved my problem... I had tried everything else, including having my drive-shaft re-balanced, tires, you name... She runs smoothly now other than needing her yearly tune-up :Woot:

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My car is doing the exact thing