I used to know how to fix this back in my youth but my memory has failed me again. My truck has some, but the Vdub which I find myself having to drive more and more it's just horrible. I think a filter goes somewhere but I don't remember what or where. Any help will be very much appreciated.

 

they have them that go into the power wire..cheap as walmart to higher price in a electronics shop..its one them parts you get what you pay for...

 

are you getting static or engine noise?

 

Besides filtering the supply voltage, which can be done with a large value capacitor, right at the input to the radio, be absolutely certain the shielding on the antenna co-ax is electrically grounded at both ends. Usually, all that's necessary is to be sure that the antenna mast mount is secure and tight on a metal body part, and the plug is properly plugged into the back of the radio.

If that doesn't eliminate the noise completely, ground wires may need to be added to "movable" body panels such as trunk and hood lids, jumpering their hinges to insure good electrical grounds for those panels. Those ground wires should not be attached at painted places, so a little scraping may be needed. Also, use "star" washers under the attach screws wherever you can.

It's a start...

Pop

 

your on the right track I have normally found with static issues it was improper ground normally at antenna mounting or body ground
Since his VW nas been sitting dormant could be corosion on coax plug
One other thing is clean antenna mast

 

I'm only getting the static when the engine is running. So that sort of eliminates a problem with the antenna ground. Does it not? Thank you all for the replies, I've been gone all day.

 

No. Not at all. That's when you WILL be hearing it.

What you're hearing is the radiated energy broadcast by the spark plug wires.

I'm assuming you're using resistive plug wires? If not, change to the "radio-suppression" type of plug wires for it, too.

Pop

 

Mark I found this on the Popular Mechanics website. i don't know if it is of any help to you.


The engine bay is usually the best place to start. Pick up a cheap AM radio-one that doesn't contain much in the way of RFI-reducing circuitry. Turn the radio on and wave it above the engine bay to scan for noise. You don't need to tune in to a particular number on the dial. Today's ignition systems can create magnetic pulses between .5 million and 1.5 million hertz, which is the same frequency range as AM radio.

With older conventional ignition systems, these pulses would emanate wildly from the coil, distributor, spark-plug wires and spark plugs themselves were it not for modern RFI-suppressing components.

Years ago, spark-plug wires were 7mm in diameter because they had a thin core, minimal insulation and little resistance. Today's spark-plug wires are a fat 8mm, with more insulation protecting a thicker graphited aramid core. This has a high resistance that changes the frequency of the still-present magnetic pulses. The same thing is true for resistor-type spark plugs. They still put out RFI, but at a hertz range that your radio doesn't pick up.

To check new or old spark-plug wires, simply take an ohmmeter to them. Remember that the aramid-core type carries a resistance of 2000 to 5000 ohms per foot, which makes them poor transmitters of electrical noise. Such RFI chokers need routine maintenance, and if they don't get it, they tend to go kablooey. Spark-plug-parts catalogs also list resistor and nonresistor plugs. For purposes of RFI reduction, always choose the resistor type.

RFI-reduction tricks

When installing a fresh set of spark-plug wires, be sure to pay very close attention to the wires' routing. Depending on the engine's firing order, the manufacturer may arrange the wires in the clips seemingly out of sequence (2-6-8-4 on one side of a V8, for example). Incorrect routing can contribute to a misfire as well.

Those plastic or metal plates that often highlight wide cam covers sometimes do more than just dress up the engine. They can also help contain any RFI that is produced by the coils and wires sitting directly beneath them. If a careless technician neglected to reinstall a cover, your sound system may not tolerate the bombardment of interference.

Capacitors and diodes

Many electrical devices on the typical vehicle have their RFI suppressed by a capacitor wired in parallel-as close as possible to the component-from the positive side of the power supply to ground. In this way, the capacitor will pass AC (noise) to ground but block DC so the performance of the component that's being silenced won't be affected. If an external mount was used by the manufacturer, the capacitor can be replaced. Internal mounting generally means the entire component needs to be replaced. It's common to find noise-suppression capacitors mounted on the inner fender wells. Sometimes there is one hanging off the primary side of your ignition coil. The key thing to look for is a good connection on each side of the capacitor.

If you suspect your fuel pump as a source of RFI, listen for radio noise just after turning the ignition on. The pump is designed to run for several seconds to build fuel-system pressure and then shut down if you don't start the engine. If the radio noise goes away when the pump shuts down, your diagnosis is complete.

Before throwing in another pump, however, try the capacitor-in-parallel trick. Depending on the pump's location, this method may be easier and cheaper. Just remember to wire the capacitor as close as possible to the source of the electrical noise.

Voltage spikes can easily cause popping noises in your sound system when certain accessories-such as the air-conditioning compressor-turn on and off. Diodes do their job by passing DC in one direction while blocking AC (spikes). Too much reverse current will cook a diode, which might be obvious if one of them looks burned. Otherwise, take an ohmmeter to each diode using both polarities. A diode should show near-zero resistance in one direction and no continuity in the other direction to pass the test.


Measure for a zero-voltage-drop reading from body ground to engine ground. Wiggle the wiring to look for intermittent or noisy connections.
RFI is also caused by obstructions to FM waves headed for your car's radio.
AM radio does not require a line-of-sight from the source to your radio antenna.
Solder, then protect, your splices with heat-shrink tubing for an RFI-free connection.

 

Jim,

Other than a bit of ambiguity in the discussion of counter-EMF clamping diode installation, the editors of Pop Mechanics did pretty well, doncha' think?

Pop

 

Yes they did.