too many grounds

forbidden wrote: You should be seeing a difference. It is all about making the flow of current as efficient as possible. Current starts at the alternator, alternator is grounded to the engine. This is why the tech guy told you to upgrade the ground from the engine to the chassis. Current needs both a + and a - to flow properly. Restrict one and it restrics the flow of current.

that totally makes a lot of sense, but would this improve or eliminate engine noise? I am going to add a couple of 4 gauges to the motor in the engine compartment... I think it would be good, but to tell me that it can affect your engine noise by not having large enough gauge... I need an explanation. Mark "Hamzter" Cinense

1991 Infiniti G20 w/JDM SR20DE

Eclipse CD8445

MTX Thunder 684

Polk DB6750

Polk DB6500

Optima Red Top in the Trunk

I added one more 4 gauge ground in the engine bay... no help with the noise... I will add probably 2 more 4 gauge cables to the motor for ground and call it a day on the grounds in the engine and chassis. I may have to look at another headunit sometime in August.Mark "Hamzter" Cinense

1991 Infiniti G20 w/JDM SR20DE

Eclipse CD8445

MTX Thunder 684

Polk DB6750

Polk DB6500

Optima Red Top in the Trunk

With all the issues you seem to be having with noise, have you insured that your ground point in your trunk with you amp and battery is good? Grounding to the body isn't always the same as grounding to the frame. Often, cars will isolate the body from the frame for road noise / vibration reasons. They should still be tied together with grounding straps, but you never know. Same could be said for the head unit. I would double check the grounds all around. If possible, check continuity between the alternator ground (engine usually) and the components. Just a thought. If this has been covered in other posts already, sorry for the duplication.

I'm just seeing (in your sig) that you have an additional component... the crossover. Have you bypassed this to confirm it's NOT that? You seem to be fixated on the HU and the grounding aspects of all of this, but I can't recall you saying anything about the Memphis piece...

hamzter wrote: I think it would be good, but to tell me that it can affect your engine noise by not having large enough gauge... I need an explanation.

If you have a HUGE power cable, but you don't allow for an equivalent or LARGER return path, if you are using all of the capacity of the power side, the current will try to find ANY WAY IT CAN to get back to the battery, and that means RCA shields, possibly causing noise...It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

haemphyst wrote: I'm just seeing (in your sig) that you have an additional component... the crossover. Have you bypassed this to confirm it's NOT that? You seem to be fixated on the HU and the grounding aspects of all of this, but I can't recall you saying anything about the Memphis piece... noise...

I did earlier in my tests bypass the crossover and go straight to the amp. I have had 2 electronic crossovers and noise is present in the system with both. I see that mjwood0 asked if I had checked the ground on the body, and I have. My battery is in the trunk and I think I am getting a good solid ground. Otherwise I think other components would be failing outside of the audio system. So, I could strap a ground to the main ground point where the battery is and the frame. I will be adding at least 2 more 4 gauge grounds from the engine to chassis. Mark "Hamzter" Cinense

1991 Infiniti G20 w/JDM SR20DE

Eclipse CD8445

MTX Thunder 684

Polk DB6750

Polk DB6500

Optima Red Top in the Trunk

So, the deck is the LAST thing you need to replace or swap? Have you tried powering the deck from the same battery as the amplifiers? By that, I mean actually running a 12 or possibly a 10 gauge speaker or power wire back to the rear battery? You will only need it for power and ground, as the accessory lead is still referenced to the chassis ground, it'll still work with the key. Also, I HAVE seen noise on the accessory lead induce noise in a head unit, but it's exceptionally rare. If you still get noise, try running another wire for the accessory to the rear battery, just for diagnostic purposes. If it fixes it, THEN we can work on getting you a solution to fix the accessory wire. From what I have read so far, it seems you have tried everything, except providing a signal from an isolated source, i.e. iPos, or walkman of some sort, or: Have you tried powering the deck while it's NOT in the dash? Have you actually connected it to the amplifiers in the back, while it is physically located in the back, and powered off the rear battery? Try that, making sure the deck remains isolated from the chassis, and powered COMPLETELY off the rear battery. Beyond that... dude, you've done EVERYTHING I'd've done, in a troubleshooting session.It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

hamzter wrote: So, I could strap a ground to the main ground point where the battery is and the frame. I will be adding at least 2 more 4 gauge grounds from the engine to chassis.

I think there is an important distinction to be made here. The chassis (frame) of the vehicle is not the same as the body (sheet metal) of the vehicle. Nor is the engine ground the same as the chassis ground. Ideally, all these should be tied together properly to make them one ground. I believe your power should be flowing as follows: Alternator --> through cable to battery --> through wire to second battery in trunk -- > through wire to amplifier. From here, the amp, speakers, etc draw power. There needs to be a return path at basically all points here. My guess is that your return path actually looks like this: Amp --> through wire to body (sheetmetal) --> through ground strap to chassis (frame) --> through ground strap to engine --> through alternator mount to alternator. You can verify the relative strength of all of these by measuring the resistance from the amp ground output to the alternator bolt where it connects to the engine. If you have low resistance, your ground path is good. What "low resistance" is really depends. Larger gauge wires are always good for high current applications. Good luck! Hope this all makes sense!

haemphyst wrote: So, the deck is the LAST thing you need to replace or swap? Have you tried powering the deck from the same battery as the amplifiers? By that, I mean actually running a 12 or possibly a 10 gauge speaker or power wire back to the rear battery? You will only need it for power and ground, as the accessory lead is still referenced to the chassis ground, it'll still work with the key. Also, I HAVE seen noise on the accessory lead induce noise in a head unit, but it's exceptionally rare. If you still get noise, try running another wire for the accessory to the rear battery, just for diagnostic purposes. If it fixes it, THEN we can work on getting you a solution to fix the accessory wire. From what I have read so far, it seems you have tried everything, except providing a signal from an isolated source, i.e. iPos, or walkman of some sort, or: Have you tried powering the deck while it's NOT in the dash? Have you actually connected it to the amplifiers in the back, while it is physically located in the back, and powered off the rear battery? Try that, making sure the deck remains isolated from the chassis, and powered COMPLETELY off the rear battery. Beyond that... dude, you've done EVERYTHING I'd've done, in a troubleshooting session.

I have isolated the deck, and I don't get any noise while the car is running. with that said, I have tried the deck when not in the dash. My battery that is in the trunk is the only battery I have. I have done the resistance check on the cable and the devices. I also have a separate 10 gauge set going from the HU to the trunk where the battery is. So like I said, the noise only happens when the car is on. I tried connecting the ground wire back to the chassis of the radio and then mounting the radio to the dash. Keep in mind the dash where the radio mounts is a steel frame then covered with plastic. I can get the noise down to a minimum by disconnecting ground and mounting the radio to the dash/console. I also did an iPod test and with the car on and the source connected to the Electronic Crossover or directly to the amp and no noise present... So, you think it could be the HU?Mark "Hamzter" Cinense

1991 Infiniti G20 w/JDM SR20DE

Eclipse CD8445

MTX Thunder 684

Polk DB6750

Polk DB6500

Optima Red Top in the Trunk

hamzter wrote: So, you think it could be the HU?

Well, if you have done all of that, and with all of the grounding efforts you have taken, I'd have to say yes, the deck is your offending component. Before you actually dump cash on another deck, see if you can borrow one from somebody... (Actually I HAVE an older Eclipse 8051 - the CD doesn't always want to load or unload perfectly, but...) You have PM.It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

Mark, New input from DYohn. I mentioned to him the fact that you have no noise (or effectively no noise) when the radio is out of the dash, but that it shows up as soon as you screw the ears in. He said your ECU is the issue. What he suggested is that you unscrew the ECU from its moorings, and see if the noise goes away THAT way, as well. If so, you'll need to either: 1: Replace the ECU, (possibly a performance programmed item, so probably not a truly feasable option) or... 2: Figure someway to isolate the ECU from chassis ground, and use JUST the ground wire on the ECU's power plug Neither way will be easy, but the isolation route will CERTAINLY be cheaper... :) Knowing that you've got all those performance parts in that car, was the ECU switched or modified in any way that you're aware of, or is it a stock ECU?It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."