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View Full Version : Strange sound at WOT (long post)



RF Overlord
02-03-2008, 11:26 AM
First, let me apologise for the length of this post...

The car is a '94 SC/AT. It had been sitting in my driveway since Sept of '02 when it was replaced with a Mercury Marauder. As luck would have it, several weeks ago my niece smashed up her Contour. My brother-in-law gave her his Taurus, and I gave him the T-bird. It only needed some minor repairs to be made road-worthy.

Yesterday, I got a chance to drive the old girl again. When I stepped on it fairly hard, there was a loud sound from the front that I can only describe as a sharp "clack". I immediately backed off the throttle and the car seemed normal. A little further down the road I had a chance to step on it again and had the same thing happen, only this time I noticed that when the "clack" sound occurred, the boost gauge went from 12 to 15 lbs. I let up again immediately and drove the car back to its new home.

The car sounds and drives normally otherwise. Has anyone heard of anything like this?

ThunderDave
02-03-2008, 11:52 AM
Did the sound you heard also have an affect on the way the motor ran or was it just a noise with no noticeable performance issue? Could be a bad motor mount. If it has seperated, it could just being moving a lot and that could be the sound you are hearing. Just a thought.

racecougar
02-03-2008, 02:47 PM
Is it a single noise, or is it a repetitive "clacking"? If it's repetitive, it sounds like you're experiencing detonation.

-Rod

RF Overlord
02-03-2008, 04:12 PM
Did the sound you heard also have an affect on the way the motor ran or was it just a noise with no noticeable performance issue? Could be a bad motor mount.The sound came in so quickly that I didn't have a chance to tell if performance was affected before I let off. Also, if it was a motor mount, why would that cause my boost gauge to go from 12 to 15?
If it's repetitive, it sounds like you're experiencing detonation.I'm very familiar with the sound of detonation, and it wasn't that. This was a single loud mechanical-sounding "clack". The nearest I can come to describing the sound is if you took one of those flat wooden paint-stirrers and slapped it down on your kitchen counter...

Tim Groth
02-03-2008, 04:32 PM
Have you checked the tensioner and belt to the super charger? Possibly some noises from the car sitting for so long...

Also have you tried looking under the hood and manual reving the motor to see if you get similar results?

Good luck on your hunt.

-Tim

RF Overlord
02-07-2008, 11:42 AM
I checked the tensioner and the belts and all seem good.

The really strange part about this is that at the exact same time as the strange noise occurred, the boost gauge, which has never gone above 12 lbs in 152,000 miles of driving, suddenly pegged at 15...

sinhumane
02-07-2008, 12:35 PM
catalytic converter breaking up? i know i was having some vac/boost issues when my mounts went fuzzy.. have they ever been replaced?

blueblur89
02-07-2008, 12:47 PM
my guess would be motor mounts. not sure why the boost gauge would do that, but i would definitely get under there and checkout the mounts. the clack could very likely be from the oil pan slamming against the k-member.

fturner
02-07-2008, 01:01 PM
The boost gauge measures back pressure, so if it suddenly jumped up, something let go to either plug the intake or plug the exhaust.

sinhumane
02-07-2008, 03:07 PM
hence the cat comment.

Melon
02-07-2008, 04:57 PM
What about SC fluid? Have you checked it? And maybe the bearings in the blower are starting to go out?

-Melon