Diagnosing noise

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DartVadar

DartVadar

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I've been driving around my 73 dart for a while now, and usually I always have the windows open so I never hear any noises on the inside, I can only hear the exhaust (Pretty loud). Today I drove to work with the windows down because it was a bit cold out this morning, and going slow up to about 25mph there are no weird noises, but once I get going above that I hear kinda a humming/whining/slight ticking noise, that increases with speed. Its not my engine, its not that kinda noise, and besides when I stop to listen the noise is fine and the engine sounds perfectly quiet up front.

It seems like the noise is coming from my cluster, speedometer. The needle bounces around pretty good under acceleration and deceleration. Could this noise be a bad speedometer cable? Or a bad speedometer. I think its accurate besides the bouncing and noise.

If it makes a difference I have a 999 trans, and I also wasn't sure If this thread should go in this section or the interior section.
 
Try testing it in different gears and different rpm's.

Does it follow the speed of the car, or engine speed?

Does it come in at one speed/rpm and leave at another higher speed/rpm, or just keep on getting worse?


That can help you figure out where and what to look at....
 
krazykuda said:
Try testing it in different gears and different rpm's.

Does it follow the speed of the car, or engine speed?

Does it come in at one speed/rpm and leave at another higher speed/rpm, or just keep on getting worse?


That can help you figure out where and what to look at....
Click to expand...

It follows the speed of the car and not engine rpms, I would hit the gas a bit and the noise didn't seem to change until the car sped up, Once I let off and the rpms dropped, the noise dropped as the car slowed down. It starts at about 25mph and slowly gets louder but doesn't go away, and its not very loud but its there.
 
DartVadar said:
It follows the speed of the car and not engine rpms, I would hit the gas a bit and the noise didn't seem to change until the car sped up, Once I let off and the rpms dropped, the noise dropped as the car slowed down. It starts at about 25mph and slowly gets louder but doesn't go away, and its not very loud but its there.
Click to expand...

Try disconnecting the speedo cable at the trans and take it for a spin and see if it goes away.

If it does, then reconnect it at the trans and disconnect it at the speedo and see if it is there or not.

If it is not, then it is in the speedo, and not the cable.
 
krazykuda said:
Try disconnecting the speedo cable at the trans and take it for a spin and see if it goes away.

If it does, then reconnect it at the trans and disconnect it at the speedo and see if it is there or not.

If it is not, then it is in the speedo, and not the cable.
Click to expand...

I will give that a try today. But what about the jumpy speedometer arrow? Kinda getting annoying not fully knowing what speed im going, where I live all the intersections have speed cameras and there are photo radar cars everywhere!
 
You can try this with the speedo cable.
Unscrew the cable from the back of the speedo & slightly pull out the inner cable. The end of the inner cable is pressed into a square shape to drive the speedo. Take a small piece of electrical heat shrink & shrink it tightly over the square end. Put a small amount of graphite powder on the speedo connection & screw the cable back onto the speedo.
Check the entire length of the cable to make sure it is not kinked or have any sharp bends. Also route it away from the exhaust.
Cheers. Gaz
 
DartVadar said:
I will give that a try today. But what about the jumpy speedometer arrow? Kinda getting annoying not fully knowing what speed im going, where I live all the intersections have speed cameras and there are photo radar cars everywhere!
Click to expand...


Go to an ACE hardware and get a can of penetrating oil called Tri-Flow. It's Teflon based and works great. Spray some in the back of the spdedometer and also maybe lube the speedo cable also.
 
Rims and caps or rings can make all kinds of sounds that are hard to resolve.
Just a reminder.
 
So I don't know what happened but the noise is definitely worse now. I did some hard accelerations and on the last one it seemed like the cable just let go or something. It started to vibrate and start reading from 40-70 in a sweep and very quickly. Once I slowed down again it caught and read accurately, but occasionally now it does that. Stripped gear in the actual speedometer or something?
 
Did you have your cluster out by any chance?

Does the speedo cable have the screw on end or the push and clip end? If it's the push and clip end, and you did mess with it I would check right there. I had an issue with my speedo jumping around and not dropping back to zero when I stopped.

I had the cluster out and when I put it back in I inadvertently had a bind in the cable which affected it in much the same way. Check the cable up under the dash and make sure it isn't at a weird bend and binding up.

IF your cable is bad, you could try and pull it, pull the cable out of the sheath and clean it. Lubricate it with a dry graphite lubricant, DO NOT use oil!
 
Also, the ends of the strand (inner wire part) are ground to a square. You have to be careful to get it properly lined up with the square mating part in the speedo. If not, it can get jammed and smashed... :banghead:
 
definitely sounds like a loose cable to me , I have had this happen where the cable wasn't in the square drive in the speedo , it pushed itself into the shielding instead of engaging the drive , try pulling it out a little then sliding it into the drive before screwing the lock collar down , it can do the same on the other end as well if your not careful , in my case I have the push on cable and it popped off the speedo but because the cable is a set length it stayed in place but the cable was skipping .
 
I did have the cluster out to clean it up and put new bulbs i. And it is a push and clip style cable. When I first got the car it did the same thing, I pulled the cable out and pushed it back in and it worked just fine. Its been working up this point. I will check again to make sure everything is lined up with the cable, and that it didn't pop out again.

Could a half in cable make it read accurately at low speeds and "slip" and go all weird at faster speeds?
 
yeah if it's not in the hole but up against it it can spin the speedo at low speeds by having pressure against the drive but slip at high speeds as it over powers the friction .
 
DartVadar said:
I did have the cluster out to clean it up and put new bulbs i. And it is a push and clip style cable. When I first got the car it did the same thing, I pulled the cable out and pushed it back in and it worked just fine. Its been working up this point. I will check again to make sure everything is lined up with the cable, and that it didn't pop out again.

Could a half in cable make it read accurately at low speeds and "slip" and go all weird at faster speeds?
Click to expand...

Being dry inside the cable housing can make them jump around irratically, especially at higher speeds.
Mine used to do that as I hit about 40 miles an hour, and the needle would jump all over the place between 40 and 90 or so and make a heck of a racket.

The inner drive cable isn't a solid piece because it is wound and it kind of winds up and releases causing the irratic behavior when the inner cable is dry.
Pull it out and coat it with some light grease (like white lithium) and I'll bet it smoothes right out.
 
I will take the cable out and lubricate everything, hopefully that helps, because it makes such an annoying noise!
 
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