Can't find good ground in trunk mustang 2017

[g3lo]

Hi,

I can't find a good ground. I am using a multimeter in coupe mustang 2017 2.3l. I sanded down to metal. When I put battery on and touch with multi meter I get 0.08 ohms consistently throughout the points I touch. The way I check it is, one probe negative battery, the other probe touches the grounding spot.

Any suggestions?

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[stang1971]

Hi,

I can't find a good ground. I am using a multimeter in coupe mustang 2017 2.3l. I sanded down to metal. When I put battery on and touch with multi meter I get 0.08 ohms consistently throughout the points I touch. The way I check it is, one probe negative battery, the other probe touches the grounding spot.

Any suggestions?

i used the spot where the spare tire would go.... sanded it down and put my ground there... not a single bit of engine noise.

 

[g3lo]

It's not about the noise. My sub shuts off after a certain amount of minutes due to bad ground and amp protection. I sanded small spots all over the area where the spare tire is. All show readings of 0.08. I need 0.02 or lower for good ground I assume?

 

[mikes2017gt]

It sounds like you sanded sufficiently. What gauge power and ground cables are you using? How many watts is that amp and/or what size fuse(s) does it have?

I used the same ground point stang1971 did. Here's what mine looked like after sanding.

And the ground attached.

My amp doesn't overheat or shut down. It's weird that the amp overheats after just a few minutes of running. Maybe your power wires aren't of sufficient thickness (gauge) and the amp is starving for power? Also, are you 100% positive that your power running running to the battery isn't nicked (cut) somewhere and grounding out before reaching the trunk? Sometimes if a positive wire is making just a slight amount of contact with ground, it's not enough to cause a direct short circuit, blowing the fuse. It just takes a few minutes for the connected device to fault out.

Also, check the + and - power terminals on the amp and make sure you don't have any stray pieces of wire touching the opposite terminal. Happens to the best of us sometimes.

 

[g3lo]

Here is my current set-up and the trouble shooting steps I took. Maybe I'm doing something wrong.

I have Alpine type r 12" subwoofer. LC2i line output convertor on bypass mode with remote wire. Remote lc2i to Alpine MRV-M1200.

Every once in a whole the Alpine amp light goes from blue to red. I beleive it's protection mode. If I turn off and on the car. It works again, until the next time it goes protect mode. Not sure what the issue is. Dead amp? Bad sub? Bad ground?

Alpine told me to test ground by using multimeter. Put on ohms. Put one probe on negative battery terminal, the other on grounding point (long wire for probes- from trunk to hood). I get reading of 0.08-0.10 when car is on. I was instructed to find a 0.05 or lower. Can't find it.

I should note the LC2i has a 1amp fuse. Could it be the fuse is loose when I drive and causes a short? If that's the case, shouldn't amp go fully off?

Hope that provides enough info for further feedback. Thank you.

 

[stang1971]

my setup is a kicker kx800.1 with a kicker cvr 12"..... my loc is a SNI-35... as you... i dont have cheap stuff and i have had ZERO issues......does it shut off at random or at higher volume?

 

[Legionofone]

Behind the carpet on the left side there is a wall that is entirely internal to the car, it has a BCM attached to it. Drill a hole through that panel clean off the paint and run a bolt through it with a lock washer and a nut.

 

[mikes2017gt]

Trying a different ground, ala what Legionofone suggested is definitely a good idea. I have some other questions though.

Does the amp only shut down after blasting for a few minutes? Does it only shut down when playing at high volumes? Years ago, I had a JBL sub and the tinsel leads were too long. When the sub would go into high excursion, it would pull the leads taught, and they would touch and short out. This is a super-rare thing, though. I'm wondering if maybe the driver itself (sub) is causing the problem? I doubt it, but it's worth checking out.

If the amp gets it's turn on signal from the LC2i, and the LC shuts off for whatever reason, the amp would shut down too, not go into protect. So we can take the LC2i out of the equation.

Still curious what gauge your power and ground wires are. That amp has 100 amps of fusing on it, so it should be connected with 4-gauge power and ground wires at a minimum.

And finally, do you have the dual 2-ohm or dual 4-ohm version of the Type R sub and how is it wired? If you have the dual 2-ohm and you are paralleling the voice coils, you're presenting a 1-ohm load to that amp, which it is not rated for. I'm betting you've got the dual 2-ohm and it's wired for a 1-ohm load and that this is the issue.

 

[SQ_S550]

It's not about the noise. My sub shuts off after a certain amount of minutes due to bad ground and amp protection. I sanded small spots all over the area where the spare tire is. All show readings of 0.08. I need 0.02 or lower for good ground I assume?

What kind of amp is this? Sounds like it might have some bad caps! .08 ohm should be fine for ground, hell that is tighter tolerance then the factory grounds.

 

[g3lo]

Hi,

A bit more info. I am running a SWR-12D4. Wires should be good as I purchased a kit recommended by crutchfield. The power and ground are a nice thick 4OHM.

It cuts off randomly. Music is playing and randomly I notice the subwoofer isn't hitting as hard. I look in the trunk and theirs a rectangle red light on the amp. The LC2I is still powered.

Could it be the 1 amp fuse losing contact in td holder, causing the amp to go into protect mode?

Running out of ideas. I looked into the left side recommendeD, but the grounding levels are the same as where I have it now.

 

[Legionofone]

My R250X1 is doing basically the same after 30 mins, I am upgrading to a R500X1 since mine is an overheating issue.

 

[SQ_S550]

Hi,

A bit more info. I am running a SWR-12D4. Wires should be good as I purchased a kit recommended by crutchfield. The power and ground are a nice thick 4OHM.

It cuts off randomly. Music is playing and randomly I notice the subwoofer isn't hitting as hard. I look in the trunk and theirs a rectangle red light on the amp. The LC2I is still powered.

Could it be the 1 amp fuse losing contact in td holder, causing the amp to go into protect mode?

Running out of ideas. I looked into the left side recommendeD, but the grounding levels are the same as where I have it now.

How is your sub wired? what amp are you running? Scratch the bad cap idea, I'm thinking your sub is wired to a 2ohm load, your amp might not be stable for the load!

 

[g3lo]

I mentioned the details above. And wired as advised by crutchfield.

Amp: Alpine MRV-M1200
Sub: Alpine SWR-12D4
LOC: LC2I

Sub wired: 4OHM to 2OHM Load

Here is a picture of how I wired it;
https://images.crutchfieldonline.co...9/ca/learningcenter/articles/1319/dvcmono.jpg

 

[mumbles]

Try to isolate this in sections. You say that you are playing music and then the subs stop playing, so...

1. Disconnect the subs from the amp and play music for a while.

• If everything is fine, then I would start measuring your subs impedance and check the wiring from the sub to the amp.

Try to get to a point where the amp stops going into protect mode.

EDIT... just looked at the wiring diagram from Crutchfield. That does NOT accurately portray your setup. Your sub has dual 4 ohm voice coils, if you wired it like the diagram (series), you will be presenting an 8 ohm load to the amp... how you connect the speaker leads to the amp will be important, and that amp might not like an 8 ohm load.

https://images.crutchfieldonline.co...0/1950/products/2016/30/500/g500MRVM120-B.jpg

In the link above, notice that there are two positive & two negative speaker terminals on your amp... you want to wire your sub in parallel (positive to positive and negative to negative) for a 2 ohm load at the amp. Consult the amp manual to see which terminals to connect the speaker leads to.

 

[g3lo]

Ok I will do that. Thank you for your help. Genuinely appreciate it. By disconnecting sub from amp you mean just pull the rca cables that go to the amp from the sub?

Thank you

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