Radio Interferences with RPM and Blinkers

[Jorge Silva]

On 8/31/2023 at 3:05 PM, visionaut said:

Are they supposed to all wire up on the bulkhead in para-serial like this? Is the coiled telephone handset wiring for dealing with the rotating axle caps?

 

How many ground locations are there? Divide and conquer isn’t for electrics…

 

Srsly I don’t believe that even @John76 can decipher what this all does. All that extra electrical stuff has gotta either turn the car into a early-style flux capacitor or into an un-earthly (pun intended) EMP pulsator…

 

Simplify grasshopper…

 

 

Well, I also don't know the purpose of all of this stuff, anyway I know that the telephone cables relay are for the auxiliary beams and I have in the dash a button where i can choose if I want to have these auxiliary lights with the normal beams or high beams or off.

 

The yellow strapped one is the voltage regulator (this one is easy)

 

Then the black next to the regulator is for the horn.

 

The other ones I have no clue what they do...😅

[Jorge Silva]

12 hours ago, Mike Self said:

In 54 years of 02 driving I've not experienced any interference on my FM band, only AM.  And I don't even have a capacitor on my alternator, the usual villain when there's "hash."  

 

Just out of curiosity, is the ground wire that runs from your alternator frame to the engine block in place, and in good shape?  Absent that wire, the alternator's ground path is pretty tenuous.  Might be worth checking.  

 

mike

 

Hi, yes the cable is properly connected from the alternator to the engine block. Thanks

 

10 hours ago, NickVyse said:

 

Like this..

 

My car doesn't have that one. Not even the lower bolt / hole.

 

It is a 1502 from 1975, European. Thanks

49 minutes ago, 66Vette said:

Jorge:

 

There are two mechanisms that could be causing your radio interference problems.  One is conducted noise, which is noise coming in on the power lines of the radio.  The other is radiated noise.  In a car, the ignition and charging systems have sharp spikes in voltage and current.  These spikes can create high frequency components that your radio can receive just like a radio station.

 

To separate the two, run your radio (while still mounted in the car) off an external battery (use separate ground and +12V connections) with the car running.  If the noise disappears, you have a conducted noise problem and you can fix it with a power line filter.  (Take Dudeland up on his offer.)  Put the noise filter right at the radio, with the ground side connected directly to the radio chassis.

 

If it is a radiated problem, grounding is your friend, resistive spark plug wires and plugs, and maybe some additional shielding of the radio may help.

 

 

I believe that should be a conductive problem, but I don't have enough knowledge about cars electricity... Thanks 

[ray_]

Of course, to acknowledge the elephant in the room, the real problem is....

 

...the radio!

 

[66Vette]

Jorge, if you have one, try connecting the radio to a separate battery, not the one in the car.  From the tests you have run it does sound like it is coming in on the +12V. 

[Jorge Silva]

6 minutes ago, 66Vette said:

Jorge, if you have one, try connecting the radio to a separate battery, not the one in the car.  From the tests you have run it does sound like it is coming in on the +12V. 

 

I will try it tomorrow, but the radio works 100% if connected to the car battery but only without the engine running or blinkers on. Nevertheless, I will try tomorrow to let the radio connected to the car antenna inside the car but connected to a different battery. Which conclusions can I take from this test? Thanks.

[66Vette]

If the noise goes away with an external battery with the engine running, your problem is noise conducted through your +12V line.  The noise on the +12V line gets into the radio and through various processes, is received as another radio signal. 
 

The fix is to use a filter like Dudeland recommended. 

[Son of Marty]

It seems to me it must be coming in on the 12v supply because the interference is still there while using the tape player which to me pretty much drops the radio and antenna out of the question leaving a internal fault on the amp or a dirty power supply as the cause. You might see if you have any a/c voltage off the alternator by putting your meter on low a/c reading and going from the alt output to ground it should be less than 50 mv 

[Jorge Silva]

13 hours ago, 66Vette said:

If the noise goes away with an external battery with the engine running, your problem is noise conducted through your +12V line.  The noise on the +12V line gets into the radio and through various processes, is received as another radio signal. 
 

The fix is to use a filter like Dudeland recommended. 

 

Hi, I tried to do this test but mayne I was not trying the proper way. I tried with an external battery but only connected the positive wire, and the negative / ground wire remained connected to the car. In this case, there is no power on the radio, is doesn't work.

 

Then I tried with + and - connected to the external battery and the antenna cable connected to the radio. In this case there is no interference with the radio and with the cassette. Neither from engine or from the blinkers.

 

 

[Jorge Silva]

11 hours ago, Son of Marty said:

It seems to me it must be coming in on the 12v supply because the interference is still there while using the tape player which to me pretty much drops the radio and antenna out of the question leaving a internal fault on the amp or a dirty power supply as the cause. You might see if you have any a/c voltage off the alternator by putting your meter on low a/c reading and going from the alt output to ground it should be less than 50 mv 

 

Hi, 

 

I followed this suggestion, could you please check if I was doing it properly as the image below? My multimeter doesn't have much scale options for AC voltage. Lower value is without the engine running. Higher value is with the engine running.

 

Thanks!

 

[slowbert]

30 minutes ago, Jorge Silva said:

My multimeter doesn't have much scale options for AC voltage.

 

Switch the multimeter to DC - about 7 o'clock on the switch dial.  

[Jorge Silva]

2 minutes ago, slowbert said:

 

Switch the multimeter to DC - about 7 o'clock on the switch dial.  

 

Like this right? Did that a couple of days ago, the voltage was within the parameters and according to the values taken directly from the battery.

[slowbert]

1 minute ago, Jorge Silva said:

Like this right?

 

Yes.  This is a good voltage reading - 12.58 volts.  I don't know what the output of your alternator should be, but normally, alternators output about 13.5 volts +/-.

[slowbert]

25 minutes ago, Jorge Silva said:

Did that a couple of days ago, the voltage was within the parameters and according to the values taken directly from the battery.

 

I missed the fact that your voltage was with the car off.  Check it again with the car running.  Should be a bit over 13V (which is the output from the alternator that charges the battery).

[Jorge Silva]

3 minutes ago, slowbert said:

 

I missed the fact that your voltage was with the car off.  Check it again with the car running.  Should be a bit over 13V (which is the output from the alternator that charges the battery).

 

Correct, with engine running seems to be everything ok.

Engine running at around 1,5k and 2K rpm. All electrics off. If I raise the engine rpm to almost max rpm, the value will not go above 14,4 Volts which means the regulator is working good.

 

With high beams and auxiliary lights on (55w each bulb) plus heater at full speed, engine at idle:

 

With high beams and auxiliary lights on (55w each bulb) plus heater at full speed, engine at 3k rpm:

[slowbert]

6 minutes ago, Jorge Silva said:

Correct, with engine running seems to be everything ok.

 

Agreed.  Your charging system appears to be functioning.  Maybe the output from the alternator is a bit weak, but that may be within specification.  (I am in the process of restoring my 2002, so I don't have an example of a running car to compare.)

 

As far as the interference problems, you can check the charging system off the list...