2011 jeep liberty big three wire upgrade

So prepping to do the big three wiring upgrade in my 2011 Jeep Liberty soon. Went outside to look under the hood and figure out how much wiring I'd need, but ran into a problem. The alternator positive to battery is simple and right on top. The other two wires I'm struggling with. 1) The battery negative to chassis factory wiring leads under where the battery is mounted into the depths of hell - where's a good alternative to run/mount this wire? 2) Totally lost where the chassis to engine block wire is ran. Can't see, no clue where it is. Any help is appreciated and if any extra info is needed to help, please say so!

These wires do NOT have to use the factory attachment points. Anyplace you can attach the wire to the block is fine. Likewise, the "chassis"... which in the case of the Liberty, is nonexistent. There is no chassis on a Liby, it's a monocoque- the body forms a space-frame, aka "cage". Attach the new lead from battery to block, and from block (same attachment point is fine and even preferred), to body aka "chassis". In the event of a monocoque ("chassis and body in one") situation, there is no ability to run a ground from chassis to body, as they are already welded into one unit."Always listen to experts. They'll tell you what can't be done, and why. Then do it. - Robert A. Heinlein"

burntkat wrote: In the event of a monocoque situation, there is no ability to run a ground from chassis to body, as they are already welded into one unit.

I usually think the opposite tho it does depend somewhat... On my older monocoques, the 'chassis channels' (rails) are still solid enough to tap if there are no existing unused threaded points. And panels are well bolted or welded unlike newer vehicles which anecdotally have insufficient welding for good conduction may need dedicated grounding. Separate chassis to body or cabs & trays can have problems if rubber mounted, but this is usually overcome with extra ground straps. But unless a particular vehicle is known to the installer, IMO it's worthwhile measuring the load voltage (across the load's +ve & -ve supply) and comparing to the battery/alternator voltage. If that is excessive, then measuring the drops from load GND and +12V to the battery -ve & +ve respectively to see which path has excessive voltage drop. (All above measurements are done with the load operating normally.)

I was being blind and didn't see the battery negative to chassis in plain sight either right next to the battery. The picture is the factory engine block ground strap. I'm not quite sure how to get to the engine ground bolt, that circled metal braided wire leads pretty far down and is hard to get too. If I can't get to the engine ground bolt, should I just pull out the fluke and start metering other more accessible bolts on the engine block to test resistance between the factory ground location and various alternative locations?

That GND looks even more pathetic than my neighbors! Forget resistance measurements. Any engine bolt point should do as should the gearbox. I have at times used existing gearbox bolts (bellhousing etc). Use the DMM to confirm that there is no voltage drop across the strap or bolt when reasonabl current is being drawn.

oldspark wrote: That GND looks even more pathetic than my neighbors!

You're telling me! [QUOTE] Forget resistance measurements. Any engine bolt point should do as should the gearbox. I have at times used existing gearbox bolts (bellhousing etc). Use the DMM to confirm that there is no voltage drop across the strap or bolt when reasonabl current is being drawn.[/QUOTE] How do you suggest doing this? I'm familiar with electronics, but not so much on the mechanical components around the engine. Are you saying turn on the engine and like a loud test tone to raise current draw and then meter the engine ground bolt to battery negative and then the ground bolt on the firewall to the battery negative to see if there is a voltage drop? or run a new wire from an accessible bolt on the engine and then check each side of the wire again for a voltage drop under load?

More to the point was that you can't test a good GND using resistance. It might be a good resistance that blows above a few Amps. And few DMMs can accurately measure 0.1 & 0.01 Ohm etc (which are 10V & 1V drops respectively at 100A).

oldspark wrote: More to the point was that you can't test a good GND using resistance. It might be a good resistance that blows above a few Amps. And few DMMs can accurately measure 0.1 & 0.01 Ohm etc (which are 10V & 1V drops respectively at 100A).

Ahhh true, didn't even consider how a small resistance translates to a massive voltage drop with a high current. So when doing voltage testing to find an alternative point, I want to be measuring between battery positive and whatever engine bolt I find until there isn't a big voltage drop (under a bigger load like a test tone/heat going)?

Not +ve. I measure the voltage (under load) between the engine and battery -ve or chassis/body and might then measure engine to the engine-bolted terminal of I have a high reading. [ I once had up to 2V between the block and 2 terminals that were heavily bolted to the block with a 16mm or 18mm (nearly 3/4") bolt! Never assume a heavily torqued metal to metal joint conducts. I disassembled and thoroughly cleaned all surfaces. That was a few years ago and I have had no problem since. Unfortunately tho the problem was detected AFTER blowing the faceplate of my Alpine HU. The bad connection meant my body voltages exceeded 16V (the alternator was sensing the battery voltage). ] BTW - you must disconnect other parallel ground straps when measuring - eg, your intact "pathetic" OEM groundstrap may be shorting your non-conducting new heavy connection. Alas that's where you need to know where (or how many) ground straps are fitted. And you probably can't use a DMM to determine that since other ground paths are likely to exist - eg, throttle & choke cables, grounded/shielded sensors, various linkages.

oldspark wrote: Not +ve. I measure the voltage (under load) between the engine and battery -ve or chassis/body and might then measure engine to the engine-bolted terminal of I have a high reading. [ I once had up to 2V between the block and 2 terminals that were heavily bolted to the block with a 16mm or 18mm (nearly 3/4") bolt! Never assume a heavily torqued metal to metal joint conducts. I disassembled and thoroughly cleaned all surfaces. That was a few years ago and I have had no problem since. Unfortunately tho the problem was detected AFTER blowing the faceplate of my Alpine HU. The bad connection meant my body voltages exceeded 16V (the alternator was sensing the battery voltage). ] BTW - you must disconnect other parallel ground straps when measuring - eg, your intact "pathetic" OEM groundstrap may be shorting your non-conducting new heavy connection. Alas that's where you need to know where (or how many) ground straps are fitted. And you probably can't use a DMM to determine that since other ground paths are likely to exist - eg, throttle & choke cables, grounded/shielded sensors, various linkages.

Ahh thanks this makes sense. So just to clarify, am I thinking about this right. Power flows from alternator positive to battery position (1 of 3 wire upgrade). Then it continues from battery negative to chassis (2 of 3 wire upgrade). The last in the circuit is chassis back to alternator ground (3 of 3 wire upgrade). This last part of the circuit is usually the 'engine block to chassis', but instead of engine block to chassis, couldn't an alternative be the alternator bolt/bracket to chassis?