Engine Whine when air con is switched on.....

**thewizard** · 04-01-2009, 06:43 PM

I am assuming that you mean 2 farad's on the cap, not amps? Also I don't mean to bust your bubble here, but that cap will do squat for your system. I run two amps in my system, a 4 channel 75x4 @ 4ohms and a huge bass amp that produces 3200 watts RMS, no cap in my system at all. I run a single battery with two runs of 0 gauge wire from the battery to distribution blocks in the back. From the blocks to the amps is also 0 gauge wire. I have absolutely no engine noise what so ever. I also have next to no voltage drop and my bass amp alone can draw 200 amps when the system is really cranked. A cap will not do what most people think that it will, as it will not give you a boost of extra power. All it will do is filter out some AC ripple and that is all. The SPL people will tell you, and keep in mind that these guys spend their lives testing their setups, SPL is always higher without a cap, it is simply another load on the system. Your larger wire, in your case the 4 gauge should run from the battery back to a distribution block, or in your case the cap (same difference as far as I am concerned). Your amps are fairly small so you could use your 10 gauge from the cap to the amps. Make sure your grounds are really good, not just so so. Make sure that the two amps are not touching each other as this can also cause noise. Sometimes even having an amp screwed down to metal can be the source of noise and the source of a ground loop which will cause noise.

**shabz34526** · 04-02-2009, 10:34 AM

hey yall... thankz for all da help... am tryin all sorts of wierd stuff to get rid of this bloody noise....... not successful so far.....i have grounded everything... the noise has reduced but not completely gone...

**merlin12volt** · 04-02-2009, 10:55 AM

There are several things I would look into. Some of them have been gone over already, but I will give you my start to finish on how I would approach this. I have been installing custom car audio and electronics since 1996 so I have a little insight into this issue.

1. What type of car Head unit Amps wires, speakers used. Not looking to brand flame but certain companies are known for certain issues.

2. Check all wiring, make sure all grounds are as short as possible all grounded to together to a good piece of chassis metal with no paint around it. Look where your Headunit is grounded. Sometimes factory ground is not sufficient and using the metal structure of the dash isn't either.

3.check RCA's.
To do this, swap your rcas for sub amp with other amps. Does the whine move to those speakers? If so, bad rcas. If not un hook rca's from headunit and leave them lay. Still there? if so unhook from amps and check. If not issue is with headunit, either the ground for it is still bad or you are injecting noise to it from an external source. Cheap headunits are notorious for this and sometimes it is easier to make them a paper weight and buy a better unit.

If it is not the head unit and all the rcas are unhooked and you still get noise, issue lies with the amp and the wiring to it power/ground wise. Post more and some pictures if possible.

**shabz34526** · 04-09-2009, 05:49 PM

hello everyone... thanks all for ur support n post..... jus a new issue that has come upnow... i hav two amp remote wires runnin frm the headunit to the amps... i grounded all at the same place.. here is my issue... the whine has increased.....it increases all the more if i hold the beam on......after all the hastle i managed to get more whine n ot reduc3e it.. n am so frustrated right nw...;-(i hav no clue as to what i need to try next....

**shabz34526** · 04-09-2009, 05:55 PM

well the system is quite simple.... kenwood head unit... pioneer speakers... 1 x sony xplod n 1 x clarion woofers..... 1 x west coast customs amp 1 x JBL amp....RCA x 2 monster cables.....

all groundz r short except for the amp in the trunk......this is a bit long coz i ran the wire from the front seat to the trunk....

**sectorz** · 04-09-2009, 06:02 PM

I think you're still dealing with a ground loop. Are any of your components (deck, amps) fastened to any metal parts?

**shabz34526** · 04-12-2009, 08:08 AM

Yes one of my amps are under the seat which is fastened to the metal under the seat..... but this amp is connected to the subwoofers and there seems to be no problem with this one...... it is the amp which is in the trunk... this is not fastened to any metal peiece. I changed both my RCA cabcles n found that the whine has reduced to agreat extend.. however it has not completely gone... what I'm going to do next is to give ground to the head unit directly from the battery negative terminal and check if there is a change... will keep updated....

**thewizard** · 04-12-2009, 12:55 PM

What are you using for a head unit, make, model etc? Some head units are prone to this and there are resolutions to the problem for some of them. It is without a question a ground loop that is haunting you and it can be elimintated completely once it's source is determined. The first step in resolving it is to understand exactly what a ground loop is. In most cases the loop is actually your amplifiers pulling their signal ground from your power ground, and in extreme cases your amplifiers actually pulling their power ground from your rca cables (this is bad). The loop can be anywhere in your system from the head unit all the way back to your amps.

**shabz34526** · 04-13-2009, 12:56 PM

Hi there,

I have a Kenwood head unit model: DPX MP5110U. I had no issues with the previous model of kenwood....

I wanna share sumthin that I just noticed the other day... may be this is sumthin normal or am being a bit dum when it comes to wires n stuff... i mnagaed to remove my head unit, i found two wires grounded at two different points... one is a black wire connected to a blackwire coming out of the bunch of wires in the factory wiring set up.... second is a blue wire from the head unit again grounded at another point. I tried disconnected one of these wires n ran the system. I did not have the whine till i turned the ac on. i removed both the grounds n found that the head unit is still running.. i found this a bit strange coz i thot the head unit always needed a ground to stay on....

now there r two wierd things that I'm finally gonna Do...get two power cables n connect the head unit with the battery directly.... n will leave the remote turn on wire as it is so the system will turn on only when the key is turned. I don knw if i shud go this route. may be u guyz cab guide me... coz as of now i hav too many power cables running from the battery to the audio system... n my efforts to get rid of the whine has been very unsuccessful.. am a lil more dan frustrated now.. coz i spend a sum on all the cables getting replaced with the best power cables n RCA i can get in town n still stuck with the dirty noise..

**thewizard** · 04-13-2009, 07:46 PM

You are sending 12V straight to ground via the blue wire, which is your power antenna wire. If you do NOT have a power antenna then that wire should simply be taped off. If it is not factory fused then this would certainly be a cause of noise. The factory wiring should more than suffice for your head unit and you there is no reason for you run wiring all the way back to the battery. And yes your head unit can still operate without the ground wire connected (although not properly) because the unit will pull a ground from your antenna amongst other internal components. You may have just found your ground loop (bingo).