AM Band on Radio Has Ticking Sound

[Dmtaurus]

Have a 2015 Edge SEL with the touch-screen, radio and HVAC controls.  When listening to AM radio with the engine running, I hear a ticking sound from the speakers that varies with the engine speed.  It is not a whine, like the noise that is generated by the alternator, but rather a ticking noise like the noise generated by a bad spark plug wire.  Since it is a 2.0 with coil on plug, I am stumped as to what is causing it.  I was trying to find grounds and I found one under the hood, on the driver's side towards the strut tower.  I cleaned it's ring terminal and applied Never-Sieze, but that didn't help.  I'm not sure where to look.  Any ideas or TSB's out on this?  It has the antenna for satellite radio, but an antenna for AM might be between the roof and headliner.     

[edjunior]

What is this "AM" radio thing that you speak of?  Oh wait.  I seem to remember hearing of this old static ridden radio signal that always fades in and out.  Okay, sorry.  I don't think I can help with this, as I really thought they had pretty much taken care of the interference from engine noise.  I pretty much listen to satellite radio or streaming anymore, so I'm not familiar with the AM.  I'm not sure I have even tried to listen to it in this car yet.  But I am interested in seeing what the issue turns up being.

[Haz]

Partial diagnostic test from the 2015 Edge Workshop Manual, and supplemental document download links below...

 

PINPOINT TEST A: POOR RECEPTION OR CONTINUOUS SEEK OR SCAN - AM (AMPLITUDE MODULATION) / FM (FREQUENCY MODULATION)

A1 CHECK THE AUDIO SYSTEM RECEPTION WITH THE ENGINE RUNNING

• Operate the audio system in AM / FM mode.

• Check the reception with the engine running, and with the engine off.

Is poor reception only present with the engine running?
 

Yes

GO to A2

No

GO to A4

  A2 CHECK THE GENERATOR

• Ignition OFF.

• NOTICE: Do not allow the generator B+ cable terminal to make contact with a conductive surface. Failure to follow this instruction may result in personal injury or damage to the vehicle.

   

  Disconnect: Generator B+ Cable C102C. (3.5L Duratec shown, 2.0L EcoBoost similar)
• 
• Start the engine.
• Operate the audio system in AM / FM mode.

Is the reception OK?
 

Yes

INSTALL a new generator. • For vehicles with the 2.0L EcoBoost (184kW/250PS), REFER to: Generator - 2.0L EcoBoost (184kW/250PS) – MI4 (414-02 Generator and Regulator, Removal and Installation). • For vehicles with the 2.7L EcoBoost (238kW/324PS), REFER to: Generator - 2.7L EcoBoost (238kW/324PS) (414-02 Generator and Regulator, Removal and Installation). • For vehicles with the 3.5L Duratec (212kW/278PS), REFER to: Generator - 3.5L Duratec (212kW/278PS) (414-02 Generator and Regulator, Removal and Installation).

No

GO to A3

  A3 CHECK THE IGNITION CIRCUITS

• Ignition OFF.

• Connect: Generator B+ Cable C102C. (3.5L Duratec shown, 2.0L EcoBoost similar)
• 

• Visually inspect the engine compartment and make sure all ignition coils are correctly and securely connected, and that there are no visible cracks in the coil housings.

• Inspect all the wiring harnesses and connectors for damaged insulation and loose or broken conditions.

Are the ignition components OK?
 

Yes	USE a jumper cable to temporarily ground various parts of the vehicle (examples include: engine, fenders, quarter panels, body sheet metal) to the frame. When the noise is eliminated, PROVIDE a permanent ground where necessary.

No	REPAIR the ignition system as necessary.

 

Document download links>

Ignition Coil-On-Plug - Removal and Installation - 2.0L EcoBoost - 2015 Edge Workshop Manual.pdf

Ignition Coil-On-Plug - Removal and Installation - 3.5L Duratec - 2015 Edge Workshop Manual.pdf

 

Good luck!

 

Edited May 2, 2023 by Haz

[enigma-2]

I seem to remember reading a few years ago where this was traced to a coil where a coil skirt was leaking spark, causing the tick, tick sound in the AM band. (Shouldn't hear it on the FM & satellite bands as the noise is clipped below the quieting threshold).

[Dmtaurus]

All great answers; thanks.

 

If I remember correctly the radio noise problem from my after-market radio days some 40 years ago, there were 2 major divisions between noise interference.  First, whining signified that it was noise generated by the alternator and this would change to a higher pitch with increasing engine rpm.  The second noise was a noise generated by leaking ignition wires or non-resistive spark plugs and the noise would change as engine rpms changed but it would not vary much in pitch.

 

Mine is the second.

 

I'll try to pull off the cover over the engine top and turn out the lights to see if any stray sparking around the ignition coils is taking place.

 

I am stumped, though, how a bad alternator can cause poor reception.  I have a 2013 Taurus and AM works great and pulls in the distant stations with ease.  But the Edge has always been somewhat lousy on AM.

 

And e2, you are right;  it doesn't make noise on the satellite or the FM band.  Their signals are clean.

 

Edited May 5, 2023 by Dmtaurus
Bad grammar.

[DILLARD000]

Not sure about your 2015, but on my 2008 Edge there is a RadioNoiseReductionCapacitor, specificly to eliminate this static problem.

Its wired to the GroundingWireTerminal next to the  main PCM computer terminals on the left FireWall above the Engine.

When electrical connections are removed+replaced, this Capacitor is often mistakenly left disconnected or never reinstalled.

Tornado\StormChasers traditionally disconnect this Capacitor so to listen for nearby LightningStrikes via the AM Radio band.

With Capacitor disconnected, can hear ignition sparks varing with EngineRPM or LightningStrikes with AMRadio tuned between stations.

Older vehicles with single IgnitionCoils have this Capacitor connected between the 12v supply wire to the Coil & frame ground.

Edited May 4, 2023 by DILLARD000

[Haz]

On the 2015 Edge, for all engines, the Powertrain Control Module (PCM) grounds terminate underhood on the vehicle's right hand side at G110, per the below wiring diagram and wiring location illustration...

 

 

 

Good luck!

 

[Dmtaurus]

Excellent hints.  I will check the G110 ground too.  I am curious about the capacitor; what does it look like? And I wonder if the 2015's had the same RNR capacitor.

[Haz]

Looking to DILLARD000's 2008 model year, Ford's online parts site shows this listing for engine-mounted capacitors, though it indicates for Gen1/Gen1+ model years, but not for your 2015/Gen2 Edge...

 

 

 

 

   

 

   

 

Good luck!

[DILLARD000]

@Haz

Yep that's the Capacitor part# 18801, just a little black box about 1"square with a wire pigtail & spade connections.

It's mounted on the FireWall frame ground post next to the PCM, pigtail end connects to the Engine ground,

so no direct connection to the 12 coil supply, kinda weird.

But seems to work as there is no ignition static on the 2008 stock AM\FM radio.

 

Edited May 5, 2023 by DILLARD000

[enigma-2]

On 5/5/2023 at 3:14 AM, DILLARD000 said:

@Haz

It's mounted on the FireWall frame ground post next to the PCM, pigtail end connects to the Engine ground, so no direct connection to the 12 coil supply, kinda weird.

 

But seems to work as there is no ignition static on the 2008 stock AM\FM radio.

 

The capacitor basically filters the Pulsating DC produced by the alternator. Smooths out the ripple to kill a whine on the AM band. Not related to filter out the tic, tic of the Ignition system.

 

On old AM radio sets, the power rectifier tube produced half-wave Pulsating DC and used 2 large filter capacitors. They were electrolytic capacitors which used a wet paste as the dielectric and when the paste dried out, they would open, producing a loud 60 cycle hum in the radio. On cars, the sound is a high-pitched  whine which varies with alternator rpm. Modern cars use a full wave bridge and the ripple is much smaller. But still present.)

 

The ticking should basically comes from the ignition system. Each coil  not only sends high voltage to the plug, but also acts like a transmitter. 

 

On older cars, we used to use plug wires made with graphite cores, which acted as resistors preventing the high voltage from radiating out. Nowadays the cars don't use spark plug wires and the coil sits directly on the plug and uses a shield to block the ignition radiation. (Why I suspected a skirt that's leaking spark).

Edited May 6, 2023 by enigma-2

[Dmtaurus]

My guess is that I should see carbon tracking around coil housing if the leakage is there.

[enigma-2]

Doubtful. Most leakage occurs down inside the socket near the bottom of the skirt.

 

One possible way to isolate the problem would be to remove each coil one at a time and see if the ticking in the audio stops. No problems for straight 4's but a pain on V-6 cyl.

 

Might be easier to disable the coil by  unplugging them one at a time and check audio. Ticking stops, you found the coil causing the ticking. 

[Dmtaurus]

Well, I removed each coil and used a 4X eye loupe to look for carbon tracks over the entire housing and in the receptacle entrance.  I found no tracks or cracks.  Each electrical plug at the harness appears to be in good condition.  What I wonder is why there are three male prongs in the coil.  There must be a dielectric test that is performed on the production line to screen for voltage breakdown, to make sure those coils are rejected before shipment.

 My guess is that one of the prongs is a ground; I don't know which one it might be. 

Edited May 8, 2023 by Dmtaurus

[enigma-2]

Did you check to see if the ticking stopped after you removed each coil? (Isolate coil-by-coil to see if ticking stops).

[Dmtaurus]

No, I did not.  That would be the next step, or, to buy a known good coil as a substitute test unit. 

 

One curious thing I noticed is that when the engine was cold, when I was doing the removing and re-installing of the coils, and next started the engine, that the ticking was gone and that it didn't come back until a later engine start up.  The breakdown of the coil must be taking place when the coil gets warmed up.

 

What I did find when looking into how the three-prong coils work is that a transistor is built into the coil that receives a signal from the PCM through one of the prongs to switch the 12 volts coming to a second prong, that is going to the wraps to build voltage to fire the plug.  The third prong is a ground, my guess for the transistor to function.

 

So what you said earlier makes more sense in that the breakdown isn't something you can see on the outside of the housing but instead takes place on the inside, where it is hidden under the encapsulant, and under a condition where the coil is somewhat warm. 

[Dmtaurus]

Well, I finally got around to performing further testing of the ignition coils.  I reviewed everything that I could visibly see and also by using a DVOM to check across the plug terminals for any resistance differences.  The meter showed meniscal differences in resistance readings.

 

So, I decided to buy new coils and replace the originals from RockAuto after reviewing the offerings and the prices  The spark ticking is now gone.  The new coils are Denso brand and the housings are almost a carbon copy of the Motorcraft coils; even the mold numbers are the same except for 2 blanked number sets.  Maybe Denso makes the Motorcraft units.

 

Thanks for everyone's help. 

[enigma-2]

I always specify Motorcraft, but good to know about Denso. Good cost savings. Thanks for posting this.

[Dmtaurus]

Another couple of things I like about the Denso part is the box says they are made in the U.S.A.; I applaud that!   The second thing is the engine acceleration is so much smoother than when the Motorcraft units were in place.  Now maybe the Motorcraft units were starting to wear out; maybe coils weaken over time rather than just quit; I never got a check engine with them.  Nevertheless, so far I am happy with the Denso performance.