Intermittent electrical issue

Besides my laundry list of brakes and squeaky poly bushings... I would like to troubleshoot my electrical issue this weekend and need help. I think it's correlated to how the engine runs rough one time and smooth the next. I discovered that something in my electrical system is noisy when I put a new kenwood HD radio in a few months back and could not pickup HD radio while driving and TONS of static on regular radio. After checking the antenna and it's cable for routing around electrical devices I discovered the issue only happens when the engine is running but not all the time when it's running though. I decided to try twisting the power and ground (not the conductors) and run straight to the battery with no change. I'm curios if this has happened to anyone else? HELP I'm going crazy chasing this down.:biggun:

duh, it's coming from your distributor or you don't have R rated plugs!!! jk... does the interference change pitch with the RPM? If yes, the resistor diode in the alternator may be at fault... Low voltage can also cause your engine to run rough. If the pitch stays constant regardless of RPM, it may be related to the fuel pump(you will hear interference with just the key on while the fp is running), blower motor(if that's it then it will change on various speeds), or it could be related to a short somewhere... my guess with the rough running correlation is that you have an under valve cover harness(UVCH) short which is causing the intermittent rough running. Also I've heard you shouldn't run to the battery with the ground, the closer to the battery the better with a shorter wire. hope this helps

Check your grounds. You would be amazed the stuff we see at work caused by a bad engine ground or body ground.

I knew I shouldn't have been cheap and bought the R rated plugsoke:
I only get the electrical noise with it running. I turned the key to run with the fuel pump running, blower motor and headlights all on and no static on the radio. Start the engine and it's back. Yes it does change with rpm. It almost sounds like the static on the radio follows the injectors firing.

alternator or uvch would be my guess

I will check the uvch for anything obvious today along with proper shielding. Can some point me in the right direction to checking alternator diodes? I do appreciate the help from every one so far. I will also look at ALL the grounds for a good solid connection. I'm gonna go have fun and I will update everyone tonight if I find something.:joy:

Thanks,
Jetfxr

It would not be hard to disconnect the alternator to rule it in or out.

I tried to troubleshoot but it didn't want to create the issue, then I got called into work. I will try again in the morning.:drool:

Using a Digital Multimeter (DMM) set to AC volts, measure the voltage directly at the alternator. There should be no more than .5 AC volts.....any more and you have a bad bridge rectifier (diode).

907DAVE said:

Using a Digital Multimeter (DMM) set to AC volts, measure the voltage directly at the alternator. There should be no more than .5 AC volts.....any more and you have a bad bridge rectifier (diode).

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I will try this when I get home. I have listened every day from home to work and back. Now it's mocking me and I can't get it to reproduce the issue. But then again I like when chit fixes itself!!

Sorry this has taken me this long, as I greatly appreciate the help. I measured AC volts and came up with .1 volts. Took the alternator out of the loop and it's still has electrical noise. UVCH are all new, gaskets are new, and external harness plugs are new. So now where do I look?