How many owners have noticed engine vibration (around 2500 rpms)?

[89Vette]

The most common cause I can think of for this is an out-of-balanced motor, bad motor mount, and/or failing harmonic balancer.

How many of you have noticed your VX having an engine vibration that's most prominent about 2500rpms? (Hint: If it's really the motor, you'd be able to feel the same symptom when stopped and in PARK!)

Thanks!
Gregg

P.S. Bonus points go to anyone who's seen/solved the problem. (There's a VX I'd like to buy, but with a vibration and the 3.5L black-cloud, I'm hesitant. OTOH, engine vibrations aren't always the short-block.)

Is there a TSB for this?

[RamAirZ]

I have the same thing, I feel it even more now that I fixed my tranny mount (I had NO bolts holding the mount to the tranny lol). I'm not toooo worried about it as it has oil, runs smooth, just has a bit of a vibration, which could just be engine design for some cars (some engines just vibrate, even in perfect running condition). I looked at it this way, no check engine lights, no other symptoms, I'm ok with it lol. I've driven a small block 350 with solid valvetrain and solid motor mounts with a 4K stall converter as an everyday driver before, so this is plush for me lol.

[VX crazy]

i have so much vibration that I cant stop driving it around......especially since Moab.....vibration AND grinding!

[SuperBoomTurbo]

i have so much vibration that I cant stop driving it around......especially since Moab.....vibration AND grinding!

You must be a nurse, right?

[SuperBoomTurbo]

For the actual post: especially in the body on frame cars of japanese origin, the motor mount Spacers were made of soft squishy rubber that all came from the same supplier. These are not like the indestructible urethane aftermarket type. After lots of hard revving or even just years of weather exposure (high heat, road salt, etc) they break down like wiper blades.

With that in mind, its easy to test. With the engine off, go push on it side to side and see how much wiggle you get. With the engine on, leave it in park (of course) and blip the throttle body through short rev ranges. Bet it moves a lot if your mounts are trashed! As the rpm's climb, the engine movement settles down as all the torque presses the engine down on the mounts.

I drove a '90 240sx for years with this same issue and didn't notice a problem mechanically til I swapped the transmission. It'd shake and shimmy at stoplights like it had a blown hemi under the hood, resulting in the occasional 'seat wood'. (TMI!!) though the lady passenger of the time didn't seem to mind.

Now if your motor vibrates when doing highway speed like something is about to explode under there (ie under load), that sounds quite a bit more complicated, and in which case, you will soon see money flowing down the street behind you in the form of engine internals becoming externals...

[RamAirZ]

lol, saves money on toys huh

[89Vette]

Is the crank pulley integrated with the balancer? Have these been known to fail? How about motor mount failures?

Are these internal/externally balanced motors?

[RamAirZ]

I remember someone talking about the 3.2's having balancer issues (balancer coming apart) awhile back. I'll ask Jerry for ya. I'm pretty sure the puller and balancer are one

[Triathlete]

Seems to me that if there was a balance issue that it would be worse as the RPMs increased and not specific to just the 2500 RPM area.
Is the engine running smooth otherwise?

[89Vette]

I remember someone talking about the 3.2's having balancer issues (balancer coming apart) awhile back. I'll ask Jerry for ya. I'm pretty sure the puller and balancer are one.

Thanks! (BTW: Who's Jerry?) FWIW, I've also heard of balancer issues in whole companies. Pioneer balancers have a bad rap after lots of failures from 2003-2008. Some even say it's still going on. (Don't know what "brand" Isuzu uses.)

Edit: If Jerry's a tech, could you (or I) ask him how to determine if the balancer (or mounts) are failing?

Seems to me that if there was a balance issue that it would be worse as the RPMs increased and not specific to just the 2500 RPM area.

Is the engine running smooth otherwise?

The engine runs VERY smooth below 2k rpms. There is no miss. Vibration does continue to exist above 2500 rpms but it seems slightly less pronounced. When I let off the gas, there is a slight stumble/vibration as it passes below 2k rpms. It almost feels like a miss. OTOH, maybe it could be the balancer "settling" back into a slower rythm. (Or if caused by a mount, maybe it's torque rebound contact/vibration.)

This could be described as harmonic vibration. The level is similar to a lawn motor above 2200 rpms. But I expect an automobile motor to feel smooth until redline.

[SlowPro48]

But I expect an automobile motor to feel smooth until redline.

Then don't buy a vehicle that has a 75 degree V6 with no balance shaft! The 6VE1 is always going to feel a little uncivilized...

[89Vette]

Then don't buy a vehicle that has a 75 degree V6 with no balance shaft! The 6VE1 is always going to feel a little uncivilized...

Are you sh'ing me? Motors (cranks) don't have a balance shaft. They have counterweights on the crankshaft.

Should I check my muffler bearings too?

[RamAirZ]

I'm thinking it's more engine design, certain "frequencies" make it worse. Mine does it but runs smooth as heck

[RamAirZ]

Jerry is like the GOD of the Isuzu world (he hangs out on the Planet alot as well as 4x4wire and a few other forums I think), he's been an Isuzu Master Tech for, well i think forever lol.I'll let you know what he says, I sent him a PM.

[89Vette]

Jerry is like the GOD of the Isuzu world (he hangs out on the Planet alot as well as 4x4wire and a few other forums I think), he's been an Isuzu Master Tech for, well i think forever lol.I'll let you know what he says, I sent him a PM.