FerdinandF150

I'll do my best to keep this short.

2011 5.0

Awhile ago I posted a video of my truck making a high pitched whistle sound only when the accelerator is pushed and I thought alternator troubles or vacuum leak. However I didn't have any of the typical symptoms. When I checked my batteries indicator it was green.

Video is here, you'll have to crank up the volume:


I recently purchased an OBDII device and Torque Pro app which reads vacuum and voltage.

I'll start with the voltage and battery:

The truck sat for about 4 days, I however didn't check the battery indicator before starting it and driving it this AM. I've been messing with the Torque Pro app and noticed the indicator on the battery is now red after driving it about 4 hours ago, but the truck starts and drives.

Here are my voltage readings

This is seconds after startup
Voltage (Control Module): 13.8
Voltage (OBD Adapter): 13.2

This is after a minute or two and with me revving the engine (roughly same voltage after a minute and not revving the engine)
Voltage (CM): 12.6
Voltage (OBD): 12.1

I think these are two different issues, but here are my Vacuum readings

The Vacuum seconds after start up:
3.2 in/Hg

Vacuum a minute or two after start up:
14.8 in/HG

I noticed it tends to bounce around a bit at idle with the cabin air on, but never really gets over 18 in/HG. It drops quite a bit when I turn on the air inside the cabin, a/c or heat, down to 10 in/HG and then shuffles between that and 16 in/HG.

Any input would be most appreciated.

RLXXI

First of all, do NOT trust that battery indicator, it's more of a gimmick than anything and completely unreliable, to test a battery properly you need to use a load tester.

Trying to hear/diag a noise over the internet (unless extremely pronounced) is a virtual impossibility.

If you suspect an engine accessory such as alternator, belt tensioner, etc... get a mechanics stethoscope http://www.harborfreight.com/mechani...ope-69913.html. That will help you pinpoint the noise.
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JCR 56

Does it make the noise with the belt off?

FerdinandF150

I'm definitely going to test the load myself and see what the numbers are.

The stethoscope is a good idea, except I only can hear it while in motion and only when i push down ok the accelerator. Doesn't mean I can't get a good listen while parked and idle.

I haven't taken the belt off.

I guess I was mostly looking for what's typical as far as numbers when it comes to the battery / alternator and vacuum.

I drove it for 20 minutes and while at speed if I let off the gas I could see the vacuum go to max 19-20.

RLXXI

There's nothing typical where the charging system is concerned as it is computer controlled, the alternator is not always charging like older vehicles, there is a strategy used to amplify economy where ever possible.

You mention you only hear it while in motion, is the sound proportional with vehicle speed eg: changes pitch or frequency with vehicle speed? Does the sound change when turning?
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FerdinandF150

Thanks, I did read that the alternator should know when to cut off and that high output readings could indicate an issue. Just have to see what the actual values are.

The sound is always the same pitch. It gets harder to hear as I pick up speed simply because things just get louder. The only consistency is that I don't recall hearing going below 25mph and I can't hear it unless I give it just a little bit of gas. Gunning it at high speeds won't recreate it.

FerdinandF150

How accurate is the red/green indicator on the actual battery?

I know I've seen it green and now it's red, will try to see if it's the original.

Scratch that. Just checked it again and now it's not a color at all. Weird.

FerdinandF150

Battery read at 12.79 and 100% chatged which is what the torque pro app was reading.

I saw a video of a guy testing for a vac leak with the MAF cleaner vs carb cleaner. Is it adviseable?