Local Ford Stumped

Pliskin

New Member
Jul 27, 2004
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So I was feeling an awkward vibration when driving and took it in to my dealer. They of course told me it was because of the aftermarket exhaust I have (refering to the x-pipe) and sent me on my way. I of course knew it wasn't and went right back to road test with the service manager. We took the car out for a test drive and, well, still couldn't figure it out. But before I tell you what he said I'll explain whats happening.

Around 60-80 mph or so (where its MOST noticable anyway) i feel a vibration in the pedals and floorboards and can hear a sound that sounds like a rubbing or grinding that fades in and out almost regularly. Excuse my stupid fake noise but its almost like vrrrrmmp.....vrrrmmmp.....vrrrrmmmp.

What we did on the test drive was take it to an old long stretch of road, get up to the speed limit of 65, put it in N, turn OFF the engine, and let the car roll. Still felt the problem and heard it. So he said its not the engine or the trans. We got back to the dealership and he told me it might just be my tires. there is a small patch on the center of one of my tires that has no tread left. So I'm inclined to agree with him. But what I also noticed was when they installed my supercharger they forgot to attatch the plastic in the fender well on the front right fender so its real loose but doesn't look like its rubbing. Thought that it could be that.

What do you all think?
 
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Sounds like a tire (or tires) that's either out of round or out of balance, or both. My recommendation would be to take it somewhere that has a Hunter 9700 Road Force balancer, as it can determine if you have a high spot in the tire, rim or both. I ran into that situation w/my 96 Cobra. We had a high spot on a tire directly on top of a high spot on the rim. The machine picked this up, and even showed the tech how far to rotate the tire on the rim to alleviate the problem.
 
Don't rule out the exhaust. If the conditions are right and the exhaust has not been neutralized properly you can have noises like this.. I would start by looking at the stuff you have changed then work your way to the factory parts.

Example...

back in the late 90's we had problems with the 4.0 SOHC explorers making a strange noise like this but at low speeds.. it turned out that the exhaust system was the cause and Ford had us install a brace, neutralize the exhaust and recal the pcm to keep it out of the spot where the vibration was at it's worse.

Lots of engineering goes into cars to eliminate noises like this. when you change the midpipe or any other part you can upset the vibration characteristics of the car. Since the noise can travel and vibrate you may even hear the noise is other parts of the car. They thought us this in the NVH school.

When I installed my off road x-pipe in my 01 gt I picked up some vibrations and I know it was installed right because I did it myself and I am a pro.. the vibrations were not bad but I noticed them
 
svttech76 said:
Don't rule out the exhaust. If the conditions are right and the exhaust has not been neutralized properly you can have noises like this.. I would start by looking at the stuff you have changed then work your way to the factory parts.

He said that the problem was still there with the car in neutral and engine off at 65 MPH. Doesn't that rule out the exhaust?
 
Marine One said:
He said that the problem was still there with the car in neutral and engine off at 65 MPH. Doesn't that rule out the exhaust?


I missed that part :lol: I somehow did not see that. I have to read a lot of threads because I moderate all the s197 forums, all of 4.6, moving pictures and the mid atlantic forum.. sometimes I skim read the threads.


yeah uneven wear in the tires can cause this too.
 
i completely spaced that. I guess it could be the clamps on the pipes. I dont know why all of a sudden they'd just start rubbing though Cause im anal about all vibrations in the car and would have noticed it right after I changed the h-pipe. After this weekend I'll be able to determine if its the wheel well piece or the tires. If its not those I'll turn all the brackets on the x-pipe to a different angle
 
Im a ford tech as well, and my god you know how many times ive had cars that had a vibration do to a tire, a wheel, or both? he said he has a flat spot. wanna correct this problem real fast? get a known good wheel and tire and put it on in the location of the tire you know has the flat spot. if it goes away, you know what your problem is. ps. a flat spot most certainly can cause the condition you refer to.
 
The vast majority of vibration complaints are caused by tire problems. If a good DYNAMIC balance does not cure the problem, go to www.gs9700.com to find the nearest shop to you that has one of these wonderful machines. It not only analyzes wheel balance, but also uses a pressure roller to check what is called Road Force Variation (RFV) which is basically checking for stiff spots.
 
MBDiagMan said:
The vast majority of vibration complaints are caused by tire problems. If a good DYNAMIC balance does not cure the problem, go to www.gs9700.com to find the nearest shop to you that has one of these wonderful machines. It not only analyzes wheel balance, but also uses a pressure roller to check what is called Road Force Variation (RFV) which is basically checking for stiff spots.

I can attest from personal experience that the Hunter machine is a great piece of gear. I had balance problems with my 96 Cobra and watching what the tech could do with that thing was amazing. Made all the difference in the world.
 
Ask your Ford Service department about TSB 0520-2. This bulletin is in regarding a rear axle problem and requires replacement of the ring and pinion by your Ford dealer.

I had a rumbling sound at speeds around 70 to 75 MPH and had my Ford service guy check it out, he knew exactly what it was.

My 06 GT is in there shop as of today, 9-25-06 to have the ring and pinion replaced.

Faspony