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Discussion Starter · #1 · (Edited)
I've created this Diagram to help you locate the Grounding Points.

Murano Z50 Body Style - 2003-2007 Main Electrical Ground Points
Product Rectangle Organism Font Art



In addition to the Grounding Points, these Muranos have Grounded Condensers (listed as ignition coil condensers when locating parts with NISSAN) that can cause ground issues when they fail.

They look like this.

.47uf P/N 28351-89901
Gadget Musical instrument accessory Bumper Wrist Watch accessory
Digital camera Point-and-shoot camera Camera Camera lens Reflex camera



2.2uf P/N 28351-89902
Brown Rectangle Camera accessory Fashion accessory Plastic
Rectangle Gas Metal Toy Wood

Rectangle Toy Automotive lighting Fashion accessory Cable




- 1 of them (2.2uf P/N 28351-89902) on the top of the engine taped to the wire harness where the ignition coil packs are connected.
Motor vehicle Automotive air manifold Vehicle Automotive exterior Auto part



- 3 of them (2 x 2.2uf P/N 28351-89902 and 1 x .47uf P/N 28351-89901) on the steel bar support under the dash cover taped to the wire harness running along the bar.
Hood Motor vehicle Automotive exterior Vehicle Gas



- 1 of them (.47uf P/N 28351-89901) on the body wire harness just under the carpet of the rear seat near the rear door on the driver's side.
Hood Motor vehicle Mode of transport Automotive design Steering wheel


Hope this helps.
 

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What kind of ground issue will a (capacitor) / condenser cause? The only issue that a failed or shorted cap will cause is to short to ground. They are used to block DC current and will pass an AC current.
So if the cap is on a line that say has 5v DC on it and is there to short noise to ground, and it shorts internally the DC is then grounded and the 5v line is then dead.
 

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What kind of ground issue will a (capacitor) / condenser cause? The only issue that a failed or shorted cap will cause is to short to ground. They are used to block DC current and will pass an AC current.
So if the cap is on a line that say has 5v DC on it and is there to short noise to ground, and it shorts internally the DC is then grounded and the 5v line is then dead.
My understanding is capacitors store energy...

I think you are referring to a diode in this response?
 

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Looking at the wiring diagram for the 1st gen ignition system, it's a single capacitor connected in parallel on the power feed to the ignition coils. Usually, this would be done to reduce radio interference caused by pulses generated when the coils discharge, which I think was what chidog was getting at. DC won't pass through a capacitor, but AC generated by the collapse of the magnetic field around the secondary coil windings can pass through (to ground). If the condenser in the diagram allowed DC to flow through it then that would effectively be a short to ground so the ignition coils would lose power. Likewise, if the condenser were to short internally then that would create a short to ground on the coil power feed causing the coils to lose power. If this is suspected, unplug the condenser (to open that part of the circuit) and the coils should get power back.

Rectangle Font Slope Parallel Diagram
 

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Great explanation!

My understanding of electricity and wiring diagrams is rudimentary at best...
 
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Discussion Starter · #6 ·
Looking at the wiring diagram for the 1st gen ignition system, it's a single capacitor connected in parallel on the power feed to the ignition coils. Usually, this would be done to reduce radio interference caused by pulses generated when the coils discharge, which I think was what chidog was getting at. DC won't pass through a capacitor, but AC generated by the collapse of the magnetic field around the secondary coil windings can pass through (to ground). If the condenser in the diagram allowed DC to flow through it then that would effectively be a short to ground so the ignition coils would lose power. Likewise, if the condenser were to short internally then that would create a short to ground on the coil power feed causing the coils to lose power. If this is suspected, unplug the condenser (to open that part of the circuit) and the coils should get power back.
The my initial post for this discussion was made to help others because
I found a failed (burst and leaking) condenser hidden in insulation of the harness for the ignition coil packs while tracing ignition coil issues. I had swapped in new coil packs thinking they had failed and still no improvements, but after I found and changed the condenser to a new one the problems went away.

This discovery prompted me to track down and examine the rest of these devices in the other harnesses of the vehicle, in hopes of getting rid of some of the other electrical gremlins in the systems. I replaced the ones mentioned in my initial post since they were old and expected to fail like the previously found one and made the initial post for this discussion.

Your explanation "I need Coffee" gave me a clear understanding how the condensers worked. Big Thanks.
 

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Right on "I need Coffee" that is what I was getting at. And Grav could you post some photos of where those capacitors are hiding at? Good catch on that problem.

And MuranoSL2003, no I was not talking about diodes, those are like one way electrical check valves. In analog electronics like audio amplifiers and radio the capacitors pass the AC information and block the DC bias currents.
 

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I'm new to the group. Just took my corroded battery ground cable off car-have to remove battery,battery box to get access. I noticed a small terminal next to big cable frame ground & small terminal on engine ground location. The 4 gauge neg cable bolts to frame & then goes to engine ground. I don't know why a small gauge wire would be needed going from frame to engine ground when battery ground does same thing. If anyone has an explanation, I'd like to know or a picture to show the 2 small terminal wire or wires. On mine,just 2 terminals-no wire.
 
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