Grounding differences

[Legacy777]

This again is sort of a continuation of topics from this post
http://bbs.legacycentral.org/viewtopic.php?t=24723

While messing around with the fuel sender I rechecked the grounds, had found that the grounds coming from the wiring going to the pump and the sender would initially show 100% continuity (0 ohms) when I touched a seatbelt bolt or other similar ground point in the rear of the car. The resistance would then creep up to .7 ohms.

I really found this rather odd. I then ran a wire from the ground point just behind the pass strut and checked the resistance between the grounds in the fuel pump wiring, as well as the chassis points I previously checked.

The ground wires in the fuel pump & sender wiring showed 100% continuity (0 ohms) all the time. When I checked the ground points, they were around the .7 ohms or so I measured before.

So it doesn't look like the chassis grounds throughout the wiring are doing a great job at keeping the chassis at the same common ground. I wonder if it has always been like that, or if it's something that has degraded over time.

Anyone experience something similar?

[skid542]

That's an interesting find. I never checked my chassis grounds beyond the engine compartment. But considering that the 'grounding mod' did show a difference in how things ran for me, it wouldn't surprise me to find that the chassis has small issues as well. I'd also venture to guess that time and corrosion would add to this.

But that's all speculation...

[scuzzy]

This again is sort of a continuation of topics from this post
http://bbs.legacycentral.org/viewtopic.php?t=24723

While messing around with the fuel sender I rechecked the grounds, had found that the grounds coming from the wiring going to the pump and the sender would initially show 100% continuity (0 ohms) when I touched a seatbelt bolt or other similar ground point in the rear of the car. The resistance would then creep up to .7 ohms.

I really found this rather odd. I then ran a wire from the ground point just behind the pass strut and checked the resistance between the grounds in the fuel pump wiring, as well as the chassis points I previously checked.

The ground wires in the fuel pump & sender wiring showed 100% continuity (0 ohms) all the time. When I checked the ground points, they were around the .7 ohms or so I measured before.

So it doesn't look like the chassis grounds throughout the wiring are doing a great job at keeping the chassis at the same common ground. I wonder if it has always been like that, or if it's something that has degraded over time.

Anyone experience something similar?

keep in mind the accuracy of your DVOM. mine is 2% +/-

1 ohm isn't going to affect anything, I wouldn't think.


but yeah, over 12-16 years, it's not far fetched to expect ground degradation

[Splinter]

How about a dual-point grounding mod?

Run another heavy gauge wire to the trunk, and start another star from there

[Legacy777]

Yeah you could do that......it's probably not worth it though. My amp is the only thing I really have grounded back there.....does .7 ohms make a difference for an amp pushing a sub.....probably not.....either way....I think it's more work then it's worth.