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!

[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?

[RamAirZ]

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

[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.

[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.

[MSHardeman]

Glad to hear that it's not just me. I tend to get a harmonic/vibration right around the 2500 rpm range that isn't really there before or after that. I just changed my timing belt, water pump and spark plugs so I know everything is good there but the vibration was there before and after all that. Hmmmm....

[RamAirZ]

Here is a response from Jerry:

THEY ARE ALL INTERNAL BALANCED , THOSE BALANCERS /DAMPNERS DONT GIVE THAT MUCH TROUBLE UNLESS THEY HAVE BEEN PULLED ON BY THE WRONG PULLER, YOU NEVER WANT TO PULL ON THE EDGES ,

IF THE VIB,S YOU ARE TALKING ABOUT ARE THE KIND YOU CAN FEEL IN THE STEERING WHEEL OR BODY , YOU HAVE MISLOCATED ENG MOUNTS , VERY COMMON, ON THESE OR THE MT,S HAVE COLLASPED , I HAD THE SAME THING ON MINE


Then I asked him what he meant by mislocated mounts:

THE FRT MOUNT S SOME TIME CAN GET TO SAGGING OR TWISTED , AND THEYA ER HARD TO SEE , BUT TAKE A LOOK AT THE FRT MOUNTS WHERE THE TOP PLATE IS BENT OVER THE MOUNT ITSELF , IT SHOULD HAVE A GAP THERE THAT YOU CAN STICK THE ND OF YOUR FINER IN BETWEEN THE TOP PLATE AND THE MOUNT ITSELF, I BET IT IS SAGGED AND TOUCHIONG USUALLY IT IS THE PASS SIDE BUT THE DRV SIDE CAN DO THE SAME, THE REAR TRANS MOUNT SHOULD BE THE SAME WAY TAKE A LOOK AT THE MOUNT AND THERE SHOUDL BE AT LEAST A 3/4 IN GAP BETWEEN THE UPPER AND LOWER PART , IN THE MIDDLE OF THE MOUNT , THIS ONE CAN BE FIXED , BY JACKING UP THE BACK END OF THE TRANS AS HIGH AS YOU CAN GET IT AND PUTTING A PIECE OF FLATTEN 3/4 IN HTR HOSE IN THE MIDDLE AND THEN LET IT BACK DOWN, THE FRT CAN BE DONE THE SAME WAY BASICALLY BUT IT IS HARDER TO DO , NOT VERY MUCH ROOM TO WORK WITH

(he's not the best typer lol)

[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...

[RamAirZ]

Like I said, for me it's plush lol. I've driven things that shook the crap out of you at idle, mostly due to camshafts and solid mounts, that and I had a Harley for awhile lol