The Lets Find The Vibration Thread !
- Thread starter TOOLOW91
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I run all poly mounts motor /trans with no problems..no vibrations in the shifter and i run a steeda shifter. I was thinking if your engine is tight and the crossmember is stiff then all of the vibration would be sent to the soft spot. My car has a small amount of vibration but it's not in the shifter or driveline..and that's normal when running poly mounts and bushing. My car handles well but the ride is almost too stiff.
Spaz
Member
I'd eliminate U-joints as a possibility, you said it had a Ford Racing aluminum driveshaft, which comes with new u-joints.
it's used out of a car that had been 9.18 on the back bumper I had to use the input yoke off my stock one because tbe splines were twisted in his so I have another to try in it . I took it from him cuz it was 80 bucks
it's been in there since before I built the car up like I said I think the dyno did it in .
I'm anxiously awaiting the results here. I doubt the flywheel is the issue. The weights are cast into the flywheel as far as I remember, I can't see this being an issue. The trans mounts is also something that I see as a non issue. The ujoints are suspect 1 to me and only take a half hour to swap out. This may seem a little crazy, but have your checked your pinon angle? If you have your pinion pointing to somewhat of an extreme and your ujoints are questionable it can cause some funky stuff back there. Just food for thought. I'm scratching to think of something beyond the obvious you've already looked for.
Damn dyno always breaking cars... I'll tell ya, lol
Damn dyno always breaking cars... I'll tell ya, lol
Just in case it should come up:
If the u-joints come out of this this thing as being the culprit, I would opt for the sealed (non-greasable) pieces. They have consistently been more reliable for me.
If the u-joints come out of this this thing as being the culprit, I would opt for the sealed (non-greasable) pieces. They have consistently been more reliable for me.
Rule #1 when troubleshooting is 'what changed?' and the very first sentence you say car ran great until after the dyno tune. So basically the tune is screwed up, the guy tuned it for peak hp numbers and ignored how it ran at the rest of the rpm range. Most likely spark timing or injector timing is goofed up. Mounts are fine, they dont create vibrations just help dampen it. Go back to the tuner or throw back in the stock tune and report back before you start ripping 
apart.
apart.
I doubt the guy who tuned it is incapable or would have let me leave with a car not running right . what I am feeling is not anything concerning spark or fuel it's a vibration . The first hour I was there was spent doing nothing but drive ability.
@93TRANSAM is the one who tuned it and is a whiz when it comes to the pms and is also who tunes @84ttops car
*Edit - And I never said the car hasn't ran great it does it has since the day it left the rollers . starts no issues and cruises stock . I had a vibration more noticeable after the dyno and I am going through the motions to find out what it is .
Not many things are re used from stock on this car so the few that are is what I am ruling out next . Something was worn and all that force on the dyno made if show itself or there's an error on my part IE maybe the pressure plate backing off on one side or I lose a dowel pin and that's chasing it .
*Edit - And I never said the car hasn't ran great it does it has since the day it left the rollers . starts no issues and cruises stock . I had a vibration more noticeable after the dyno and I am going through the motions to find out what it is .
Not many things are re used from stock on this car so the few that are is what I am ruling out next . Something was worn and all that force on the dyno made if show itself or there's an error on my part IE maybe the pressure plate backing off on one side or I lose a dowel pin and that's chasing it .
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A vibration in the tune... Not a chance. If that's the case I will be having vibrating seats tuned into mine lol
Fair enough, just when I read this part of your opening post:
"Ok so I put my car together as most know it was great I ran it almost 200 miles everything was awesome . Had the car tuned and after the dyno we now have a vibration that comes on about 2200 rpm and up and I get a nasty rattle in the shifter area . "
It definitely points me towards the tune.
That said, I don't know what your vibe 'feels' like. It seems like it's speed independent, happens at specific RPMs, moving or still, can you clarify that ?
The tune could affect the timing, injector timing and air/fuel ratio all that can cause 'vibrations' of sort, so I still wouldn't rule it out based on what I've read here.
I have a wide band in the car if the AFR was out id see it real time . this feels like a drive line based or balance vibration not something that would come from detonation .
it's not horrible unless I have it under a super hard load but it is there 2200- and up and 4th gear seems to be the smoothest at about 65 .
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Did d/s today and it deffinitley drives smoother so I am sure those universals in that drive shaft are junk . but the vibration is there. I am gonna prob pull TRANS tomorrow and check it all out I did doubles back to back last two days so it's time for bed !
oldskolbus
Founding Member
I haven't seen it posted yet. If your only getting it at the certain rpm, have you balanced the tires? If so how long ago? They can come out of balance by hitting a curb, rock, or a big pot hole. Unbalanced tires can give you a vibration at a certain rpm, then go away.
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