Radio noise and auto turned off and on

[mxanotcar]

Monday 11/3/2014.  Weather temp 43F.  Time around 6:40am. Driving on highway.  Radio has been on since the car started 30mins ago.  Around 6:40am, there as some kind of static or sound like from firework sparking stick that was coming from the speakers for serveral minutes.  I thought may be the radio channel need to change.  But before I changed it, the radio screen was turned off and blank, and the radio channel still was playing.  And then the radio screen was back to normal being on again, the radio channel was still playing, but the sparking noises from the speakers were gone. 

 

This has happened one time.  Bizzare?

 

And yes yes, I only have the basic model with radio equipment only. :)

 

[SilverSurfer]

Had a similar sound coming from my SE Hybrid no nav package, although with the radio off.   Personally would have described the noise as light scratching or feedback static, but if it had been much louder the sparkler sound could have applied.

 

Not very loud and went away (or to quiet to be decernable) when radio turned on.  Never isolated where exactly the noise was coming from and seems intermittent at best, since I've been unable to make it happen on demand.  My concern was it might indicate a short somewhere in the speaker wiring, but have not had much luck nailing down if it's coming from one/all speakers, initially thought it could have been some kind of vibration / road noise as it seemed to coincide with ICE on and a certain RPM range when puttering along on the last leg of my return home, from what little troubleshooting I've been able to do the 2 or 3 times I've thought I heard it.

 

Kinda wrote it off as a mysterious Gremlin I'd only have to chase down if it became a regular occurance, much more noticeable than the vague scratching noise I 'thought' I heard a few times, or fell victim to 12V battery issues.

 

My thinking is:

1.  Possible EMF interference from a specific RPM / split mode combination, either from some kind of ignition timing sweet spot or power levels on MG1 or MG2 running close to idle easing back into the neighborhood.  Although I would expect this to be more of an issue with AM reception, not creating some kind of static coming from speakers with radio off.

 

This thought is due to issues with my 94 Ranger and AM radio.  Engine on vs off would seem to weaken the strength of the incoming station, although climate control fan speed seemed to cause the most interference when traveling and starting to lose the station.  Hi speed fan would crackle much more than the low speed setting.  Engine off would eliminate all interference and give the strongest/clearest signal depending on station.  (Lights on/off seemed to change things as well, but think that had more to do with AM stations reaching farther at night, cant recall if there was something in the radio that changed to allow you to pull in those far flung stations at night with the lights on.)

 

2.  Some kind of harmonic vibration from that particular low RPM / low load state.

(Seemed to be coming from close to the windshield on one/both? sides and to vary with gas pedal input or disappear with ICE off)

 

3.  Speakers bleeding some kind of odd capacitance that had accumulated in the circuit or left over in a capacitor somewhere after turning radio off.

 

4.  Biggest fear -  Some kind or transient short in the speaker wiring.

Since it was present with radio off, primary concern was that if there was a short, 12V battery drain while parked would be an issue.  Mainly just from paranoia over the other battery issues from MFT not properly shutting down, etc. 

 

Haven't really thought about it in a few weeks, like you seemed like a bizarre freak occurance. So will try to remember to keep an ear out for it.  Only seemed to occur for me at night with radio off and ICE on for me, but may have still been there when I turned radio on as well to check.  Was barely audible to the point I wasnt sure I wasnt just hearing things or possibly hearing some faint 'new' engine noise that the hybrid makes that would eventually be an audible que, like the manual shift point hums of the old Ranger.

Edited November 9, 2014 by SilverSurfer

[SilverSurfer]

Found this tidbit on the energi forum when googling my way around the squeaky block.  Found a few TSBs for other Ford models that had similar points of squeak that may sound like they are coming from speakers fixed by placing the tape in just the right place, but nothing CMax specific yet.

 

 

The dash rattle, they took apart the dash and found nothing loose like fastenerS, glove box, scuff molding etc.  What they did find was (this is taken from my work order) "found window washer bottle base number 17618 rattling on the right front fender. Used PVC tape part #164-R4901 to pad between bottle and fender. Noise no linger present). They used the tape to wrapped around the wires/hoses that were right up against the fender to the left of the washer bottle. It didn't happen a lot but I will keep an eye on it and let you know if it appears again.

 

Other suggestions were pushing on glove box when heard to see if it's the culprit and/or something in the glove box vibrating.

Climate fan speed was also mentioned, but I hear the dash noise with climate completely off.

 

This seems like the probable source of my sound given recent top off of washer fluid during my last visit to the dealer and only hearing when engine is running (generally only heard at zero/low throttle and goes away with a little more foot or engine cutoff).  May take me a few days to try the fix on mine due to chilly weather curbing my enthusiam for ghost hunting for noises with the engine idling in the yard and no PVC cushion tape lying around the house. 

 

Still hunting around to see if I can find a TSB specifically referencing where to put the tape, how big a piece is needed, and will check to see if the dealer will take care of it for me, if I cant find something handy around the house to serve this purpose.  Sounds like if this is the problem the tape needs to go down around the base and not the filler neck which was my first thought when seeing the issue may be related to a full washer fluid bottle.  But will have to take a look when the sun comes up tomorrow.

[mxanotcar]

So far my CMAX has two different noises with the first one sound like the one you SilverSurfer posted above.  That first one has been around for many months now, and I have not been sure what cause the rattling noise.  It seems coming from the passenger side dashboard, and it not always rattling but may be it always does that but the radio volume cancelled it out if the volume on hi.

 

I have not heard the 2nd one "firework sparking stick" coming from the speakers since that day.  May be the solder or welding parts finally soldered and welded electronically from short circuting :)