RADIO NOISE? High pitch whine!!!

[Buzzard78945]

Ok so I’m a Diesel Technician, not a radio technician I’m working on it.....

My truck, a 07 Dodge Ram 2500 with a Cummins Diesel engine has a high pitched whine noise with all radios ( narrowed it down to the truck Wife’s truck don’t do it ). High pitched whine when I start the truck, worse when I drive, AND stationary when I rev. the engine the RPMS change the noise higher pitched and louder... engine off noise gone... higher RPM more/louder noise


through process of elimination (I have 2 batteries yes I know they are connected together no it don’t change noise either batt ) I’ve tried moving the power and ground to numerous locations no change, I hooked the power and ground to the alternator (see if it’s way worse) no change


THEN! I got to thinking what else is controlled by a signal... the injectors are 80v PWM controlled by the ECM... so I disconnect the forward valve cover plug ( front 3 cylinders only) engine is stuttering running rough (only off of rear 3 cylinders ) and you can hear the noise change... it’s not a smooth sound any more, it sounds like a stutter like the engine is now running....

What can I do as far as a noise compressor?
I’ve seen some bad results in the way of noise compressor causing issues on a scope you can find that video on YouTube idk just what I seen on there

what can I do to limit the noise coming through the power/ ground circuits supplying the radio?


Also I’ve looked into wrapping the power supply in
Ferrite ...

Any suggestions?
Any input is appreciated obviously any knowledge is out weighing mine at this point...

thanks for all the help!

 

[Mustang 131]

The Radio Shack *Flavor Radio" is great for narrowing noise issues.
Usually the fan, fuel pump or wires. Guess you can eliminate some of those already.

 

[Buzzard78945]

Antenna grounded good! Resistance checked from mount to battery negative perfect connection... Also coax routed from antenna @ headache rack (on flat bed) through beer window (rear center sliding glass window), under back seat to under front seat by center console... (not near any electric motors) I don’t know what brand coax most likely not super expensive one... May try different coax and see if it helps

 

[Buzzard78945]

The Radio Shack *Flavor Radio" is great for narrowing noise issues.
Usually the fan, fuel pump or wires. Guess you can eliminate some of those already.

Well fuel pump runs for 10 second when key is first placed in the on position... I would have noticed that noise for that duration only (not it)

the blower motor is 99% of the time not running in my truck ( I’m in Texas it’s February and it’s 75 today)

what other “wires” are you mentioning...? I would understand if it’s a small block chevy with a distributor but no distributor here it’s a diesel...

 

[Buzzard78945]

The Radio Shack *Flavor Radio" is great for narrowing noise issues.
Usually the fan, fuel pump or wires. Guess you can eliminate some of those already.

I’m not really finding anything on “flavor radio”...?

you may have to help me with that one if you got a link thanks

 

[Redbeard U812]

Have same truck. Run a ground from case of radio to frame, can be alligator clips to start. Try bonding the bed to frame, cab to frame. Can use wire to start. A simple RF noise suppressor before radio. Ferrite beads. Here is a good link....

http://www.k0bg.com

Once I bonded my cab and bed. Noise went away.

 

[TM86]

I’m not really finding anything on “flavor radio”...?

you may have to help me with that one if you got a link thanks

Any cheap battery operated pocket sized radio should work.

The "flavor radios" were small AM radios RS sold in a variety of colors. Here's a link about them: https://www.retrothing.com/2010/04/radio-shacks-classic-flavoradio.html

 

[Redbeard U812]

Any cheap battery operated pocket sized radio should work.

The "flavor radios" were small AM radios RS sold in a variety of colors. Here's a link about them: https://www.retrothing.com/2010/04/radio-shacks-classic-flavoradio.html

That's ok for snooping around neighborhood.....but not very good around a diesel truck.

 

[Handy Andy]

But, how well is the Engine bonded to the Trucks Frame?

Any long cable is suspect as an antenna for noises.

Surprised that you hear this noise, but it has not set any Check Engine Light or Service Engine Soon error code.

Because...

With that much noise in the system, it's hard to track down any simple error code due to the sheer volume of noise the sensors have to fight to send their data thru. So if you get poor performance, this may indicate your issue is with noise getting picked up by the system as it has to figure out performance under loading conditions like, knock - pressures, air, throttle position as well as emissions.

What about your SRS (Air bag system) - if you've got that kind of noise I'd be looking into seeing if more than one section of your vehicle needs better grounding. Any false signals can create a trigger you don't want to happen.

• What I've learned thru the years is, is not just how well your system is grounded to the frame. But how well the systems are tied together and grounded properly.
• You can bond parts to the frame, but that does you no good if the Frame isn't bonded to where those parts needs to return their electrical energy...
• You can wire a solenoid using two or three wire back to the board, or to a harness - but that does you no good if that harness or it's tie off to ground is poorly designed. it's the reason why you get noise, from the opposition of flow of current thru your system - a field is generated by it - and if you can't reduce the inductive effects of that - your wire radiates.
• These problems can wreak havoc on CAN systems that are used in newer vehicles these days. For if there is too much noise - it can't communicate.

So you may need to look further into the Tie offs, where the grounds that occur - are tied off without faulty grounding problems like poor crimps or paint under the lug to the frame or body panel.

Ok, let's see if you have any engine chassis to carriage (where the engine mounts to the frame or it's cross member to the frame if you need clearance) - as well as where the engine grounds to the Frame. I'd look for braiding lugs attached around points of Engine Mount cross straps from Engine chassis to Frame Chassis for less inductive and radiative path to battery or frame grounds.

Seriously, for you may show good ohmic readings. However, there is something in there with a lot of inductance making it a good antenna for your radio to pick up as noise.

So it can be from the harness and it's ground points onto the ECM - if it's in the engine compartment, onto a noisy fuel pump and you have to figure out where, and if, and are there, any - good grounds are that you can find that help level the ground plane and eddy currents that form from the other grounding locations not getting thru back to the battery - you can have radiating panels that are grounded by wire, maybe even a bolt but not by shielding - for the panel may re-radiate any noises that the ground point in the section places on it.

 

[Redbeard U812]

Another thought, led lights. Led lights, like headlights, or offroad will make noise.

 

[Buzzard78945]

Have same truck. Run a ground from case of radio to frame, can be alligator clips to start. Try bonding the bed to frame, cab to frame. Can use wire to start. A simple RF noise suppressor before radio. Ferrite beads. Here is a good link....

http://www.k0bg.com

Once I bonded my cab and bed. Noise went away.

ill try the ground to radio case... but I would think not all of my radios have a case ground issue ( my wife’s truck all the radios don’t have any noise )

my antenna which is grounded perfectly to my batteries ohm tested directly to battery with a $350 true RMS SnapOn multimeter

Noise suppressors I’ve seen affect wave form on a scope so I’m Leary of them

 

[Redbeard U812]

) I don’t know what brand coax most likely not super expensive one... May try different coax and see if it helps

Running dual antenna?

 

[Redbeard U812]

Go through the link I sent. Lots of information, Handy Andy describes alot of issues that are related to bonding. Dodge has poor ground straps. I had to add wire braid to mine. Also, braid from exhaust to frame in three locations. Sounds funny but works.

 

[Buzzard78945]

But, how well is the Engine bonded to the Trucks Frame?

Any long cable is suspect as an antenna for noises.

Surprised that you hear this noise, but it has not set any Check Engine Light or Service Engine Soon error code.

Because...

With that much noise in the system, it's hard to track down any simple error code due to the sheer volume of noise the sensors have to fight to send their data thru. So if you get poor performance, this may indicate your issue is with noise getting picked up by the system as it has to figure out performance under loading conditions like, knock - pressures, air, throttle position as well as emissions.

What about your SRS (Air bag system) - if you've got that kind of noise I'd be looking into seeing if more than one section of your vehicle needs better grounding. Any false signals can create a trigger you don't want to happen.

• What I've learned thru the years is, is not just how well your system is grounded to the frame. But how well the systems are tied together and grounded properly.
• You can bond parts to the frame, but that does you no good if the Frame isn't bonded to where those parts needs to return their electrical energy...
• You can wire a solenoid using two or three wire back to the board, or to a harness - but that does you no good if that harness or it's tie off to ground is poorly designed. it's the reason why you get noise, from the opposition of flow of current thru your system - a field is generated by it - and if you can't reduce the inductive effects of that - your wire radiates.
• These problems can wreak havoc on CAN systems that are used in newer vehicles these days. For if there is too much noise - it can't communicate.

So you may need to look further into the Tie offs, where the grounds that occur - are tied off without faulty grounding problems like poor crimps or paint under the lug to the frame or body panel.

Ok, let's see if you have any engine chassis to carriage (where the engine mounts to the frame or it's cross member to the frame if you need clearance) - as well as where the engine grounds to the Frame. I'd look for braiding lugs attached around points of Engine Mount cross straps from Engine chassis to Frame Chassis for less inductive and radiative path to battery or frame grounds.

Seriously, for you may show good ohmic readings. However, there is something in there with a lot of inductance making it a good antenna for your radio to pick up as noise.

So it can be from the harness and it's ground points onto the ECM - if it's in the engine compartment, onto a noisy fuel pump and you have to figure out where, and if, and are there, any - good grounds are that you can find that help level the ground plane and eddy currents that form from the other grounding locations not getting thru back to the battery - you can have radiating panels that are grounded by wire, maybe even a bolt but not by shielding - for the panel may re-radiate any noises that the ground point in the section places on it.

I understand completely where you are going with the ground situation I’ve chased my tail many of times with ground issues... I did run a jumper from battery negative (where radio is grounded at on the battery terminals ) to the antenna mount.. same issue... I also know for a fact the engine ground (block) to battery is good, and the bed to frame ground is good and the frame ground to battery is good

 

[Buzzard78945]

Another thought, led lights. Led lights, like headlights, or offroad will make noise.

No LED’s except light bar in grill but don’t use it unless I’m off road,,, good to know food for thought

THANKS!