Del, a question for you.

[RustyRatRod]

Non Mopar related, but could be used to help Mopars too.

2004 Ford Ranger, 3.0 V6, auto. Stock non pioneer Ford radio. I am experiencing ignition noise especially at idle. If I tune it to a frequency where there's no station, it's pretty loud. It is also very noticeable on somewhat weaker stations.

It is not "one", it is all six. After I did the heads this last time, I added new NGK plugs and wires. Gapped the plugs to factory spec. All the wires are routed away from manifolds and through the stock wire looms and clips.

There are no broken wires and no sparks that I can see at night under the hood. The truck does not skip and runs flawlessly. No codes or pending codes in the computer.

Here is the possible culprit. The only thing not stock on the ignition is an MSD coil pack. I put that on with the plugs and wires. It is hotter than stock. By a good bit according to MSD. I got it because it was about the same price as a stock coil.

Is the coil possibly the culprit, or should I look elsewhere? What other possibilities could be causing this? I double checked all of the grounds and they are all hooked up from when I did the heads and all clean and tight.

Any insight is greatly appreciated.

 

[67Dart273]

I'm not familiar enough with these to be too specific. MSD makes a lot of energy, but so would have the factory stuff

What do you have for an antenna? A broken coax shield could do this. Another is poor hood grounding. Try running at least two ground braids from the hood to the firewall, leaving just enough slack for the hood movement.

Two-way shops normally have add on springy contacts that you screw to the hood or fenders so that when the hood closes, ground shield is improved



Where is the actual ignition "module" if you will? That is, whatever actually generates the pulse and feeds to the coils. If this is poorly grounded, could be a problem. So could wire routing, "lay." Just running wiring "close" to ground, IE cable dress will affect noise radiation.

So will two conductors improperly routed too close, as in power going to some interior device. If you have any added wiring, tach, stereo, CB take a good hard look or temporarily disconnect.

Sometimes bypass caps help on power leads. The old old "standard" used to be "coaxial feedthroughs." You don't need those, but wiring in wire lead ones, need to be careful as to not cause shorts

I haven't seen any for years, and had a hard time finding a photo, LOL

 

[clhyer]

Hey Rob,
Did this noise just start after your last "head job"…
C

 

[RustyRatRod]

Hey Rob,
Did this noise just start after your last "head job"…
C

I am not sure. It is not noticeable at all once engine RPM is at 1500 or above. I cannot remember if it was there before or not.

 

[67Dart273]

Darn that would be a help, indicating of course something that's changed

 

[TrailBeast]

It could even be the new plug wires Rob.
Are they stock suppressor style or some "performance" style?
One easy thing to do that could also make a difference is a condenser connected into the power supply side of the coil.
You can temporarily connect the condenser to the positive terminal on the coil, then ground the canister end anywhere you can and see if that clears it up.

This was the old school way of dampening ignition noise with most points ignitions.

 

[RustyRatRod]

These are my plug wires:

http://www.summitracing.com/parts/ngk-52014/overview/make/ford

This is my coil:

http://www.summitracing.com/parts/msd-5529/overview/make/ford/model/ranger/year/2004

Thank yall for the ideas. If it is the plug wires, I will just live with it. It runs very good and like I said has no codes.

 

[SpikeWills69]

What do you have for an antenna? A broken coax shield could do this. Another is poor hood grounding. Try running at least two ground braids from the hood to the firewall, leaving just enough slack for the hood movement.

Two-way shops normally have add on springy contacts that you screw to the hood or fenders so that when the hood closes, ground shield is improved.

:glasses7:I haven't thought about this in years, but your comments reminded me. My sister had a 67 Mercury Cyclone 390 back in the day. The radio would have a similar interference at idle. They came with fiberglass hoods with a metal mesh/screen in the fiberglass (if memory serves me) that was supposed to prevent it, but it didn't work 100%.

She took the car back several times, but the dealer didn't have a fix.

Hope you find the culprit Rusty.

 

[67Dart273]

Yep. Remember the shielding for Corvettes?

 

[SpikeWills69]

Yep, on the corvettes.

 

[RustyRatRod]

The antenna is stock, the coax is untouched and perfect. Everything is stock except what I mentioned. I guess it may be the nature of the beast.

 

[67Dart273]

I would not think so. I don't listen to AM much at all anymore, all there are is radical right or radical left politicos. But I would not expect what you describe