List of factory ground connections

lunchbox3

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I've been getting such bad alternator whine on my CB it's unusable when driving. I'm trying to figure out if maybe a ground connection installed at the factory has been removed or has broken off. So far I've freshened up the ground points and bolts:
-on the hood
-in the top center of the firewall
-the bolt where the hood strap goes to the block (this was dirty and didn't seem like it would make a very good connection...)
-Where the two ground straps from the battery run to (I forget where these were)

Where are other places that I should check?

If it helps, I'm not getting much noise with the antenna unplugged, but haven't done a true test of that yet. Does that suggest that my rear tail light mount isn't grounded well enough? I believe it was installed correctly - I followed directions here and elsewhere, and it tested fine, but this whine has always been a problem.

Edit: the power and ground for the CB is run through the firewall directly to each battery terminal.
 
I too am fighting this problem. I've checked my coax and changed my power lead but still no luck solving it.
  • 😕
 
Most of the noise is the fuel pump on mine. I have a handheld CB and it makes no difference with totally isolated power and ground. I moved my fixed antenna to the front bumper and it's a bit better but still not great. Even with chokes and a new fuel pump it still makes a huge amount of RF noise, you can detect the fuel pump from a few feet away using the handheld. It would be nice to know why some people have trouble with this and others don't.
 
Page 1048, this is for the 1998 service manual though because we don't have the 1997 listed here (it's a later model for some reason). Basically look at the screenshot of the table below in the PDF for anything that starts with "G", e.g. "G103".

Also on later pages you can see pictures of the locations mentioned, the last column in the table refers to which figure.

Good luck, there's only 14 ground locations (probably) for you, most seem fairly accessible. I'd just go through them all and clean off the surface and the contact thoroughly then reattach them starting from the easiest to the most difficult.

77097


77098
 
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Most of the noise is the fuel pump on mine. I have a handheld CB and it makes no difference with totally isolated power and ground. I moved my fixed antenna to the front bumper and it's a bit better but still not great. Even with chokes and a new fuel pump it still makes a huge amount of RF noise, you can detect the fuel pump from a few feet away using the handheld. It would be nice to know why some people have trouble with this and others don't.

You can tell if the fuel pump is a problem by turning the ignition on but not starting the engine. The pump will run only until the fuel is brought up to pressure (about 2 seconds) and then shut off. So if you get a 2 second burst of noise when the ignition is turned on followed by nothing it is likely due to the fuel pump.
 
Funny thing is that the same mount was quiet with an SF-2 antenna on 2m. Most of the time I use 2m or 440 these days so I haven't looked into it recently. The pump really howls at 27mhz, have no idea why.
 
Funny thing is that the same mount was quiet with an SF-2 antenna on 2m. Most of the time I use 2m or 440 these days so I haven't looked into it recently. The pump really howls at 27mhz, have no idea why.

If you think the fuel pump is bad, install a Banks turbo with intercooler. The intercooler water pump lights up the red overload light on my CB. I have quieted it down somewhat with chokes, capacitors and grounding, but it is still the dominant source of 27 MHz noise.
 
Page 1048, this is for the 1998 service manual though because we don't have the 1997 listed here (it's a later model for some reason). Basically look at the screenshot of the table below in the PDF for anything that starts with "G", e.g. "G103".

Also on later pages you can see pictures of the locations mentioned, the last column in the table refers to which figure.

Good luck, there's only 14 ground locations (probably) for you, most seem fairly accessible. I'd just go through them all and clean off the surface and the contact thoroughly then reattach them starting from the easiest to the most difficult.

View attachment 77097

View attachment 77098
Oh man this is great. Thanks!

I’ll have to do the fuel pump test. It seems to vary with my RPMs so I assumed alternator whine, but now I have another possibility, so thanks!
 
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Brushless intercooler pump! Probably the most expensive way imaginable to reduce RF noise.

I did a quick search for "brushless intercooler pump" and came up with one for a shade under $1k. I'm not going there. I'll just live with the noise.
 
You can tell if the fuel pump is a problem by turning the ignition on but not starting the engine. The pump will run only until the fuel is brought up to pressure (about 2 seconds) and then shut off. So if you get a 2 second burst of noise when the ignition is turned on followed by nothing it is likely due to the fuel pump.

A good fuel pump will only run for 2 seconds whn key on on position? or would it continue running?
am trying to figure if my pump is bad. crank no start