Rick:

Not sure what you mean by "common grounds", but you don't want common grounds in this case.

You probably have a ground loop, although it could be power line related. You should be able to figure it out and eliminate it with the following guides.

Look at the tips here, particularly at the alternator whine section:
http://www.termpro.com/articles/noise.html

This source has a good diagnostic plan:
http://www.mobiledynamics.ca/resourc...OUBLE-8-11.pdf

This Crutchfield guide might help too:
http://www.crutchfieldadvisor.com/IS...int=1&page=all

Try turning down the gain on your amp. I had a lot of noise on my speedster replica, and it turned out that if I turned down the gain, I could still split my ears, but had to simply turn the radio up more--until the signal I wanted really overwhelmed the signal I didn't.

Bill,
This is what I meant by common ground. Thanks for your suggestions, and also Brian's. When the weather warms on a day off I will see if I can improve on the "professional" installation.

"(A) Prevent "ground loops" to reduce noise from galvanic conduction and intermingled currents:
1. Adhere generally to a "star ground" system design in which the Power Ground, Chassis Ground, and Signal Ground connect together at only one single point at the head unit.
2. Signal Ground should remain relatively isolated within each component, except the head unit.

3. RCA connectors' exposed wiring or shields (Signal Ground) should also remain isolated and not contact power wiring or any chassis.

4. The Chassis Ground of each component should also remain isolated. If Chassis Ground is not internally isolated, that component's chassis should be isolated from the car's chassis.

5. Power Ground wiring from all components should connect only at a common point on the Ground terminal of the car Battery, and not just to the nearest metal point on the car chassis.


Ground Loop Note: In general, all ground wires should be returned separately to a single Common Ground Point in order to avoid noise problems in high-current circuits due to "Ground Loops."
"Ground Loop" is the term used to describe situations in which a difference of potential exists between two "ground" points (which one would be the true ground?). Ideally a ground is a ground, but this would require ground conductors with zero resistance.

Since real-world wires -- including all metal chassis and "ground" wires of any size -- possess finite resistance that increases with length and constriction, any currents running through them will cause finite voltage drops to exist. Therefore, the only true Ground in a circuit is not a "Ground Wire" but a Common Ground Point.

Without separately returning all Ground Wires to a Common Ground Point, Ground Loops may occur as currents unintentionally intermingle and cause unwanted voltage drops and consequent noise. If two or more ground wires connect to different points along a path there will be voltage drops between them. In contrast, if two or more ground wires connect to the same point, that point becomes the "Common Ground" and Ground Loops involving separate ground wires can not exist.

--adapted from National Semiconductor"

Hmmm....interesting...hey, we are hijacking this thread...I will start another audio thread in a bit.

From earlier in the thread, the limp home mode can be disabled using the following according to DR:

The ignition monitoring relay can be bypassed using the bypass relay, part #928.615.175.00, cost $16.23. see... https://www.928gt.com/images/product/medium/25846.jpg

Where does the bypass relay install?

Thanks.

Passenger footwell, next to the LH/EZK brains. You unfasten, unplug and remove the stock relay (clear case with LEDs inside), and insert the bypass relay into the plug.

:_otopic: I have a BMW that keeps frying smallish ground wires when it is trying to start. Once started there is no problem. When I increase the ground wire size from engine to chassis, the wire lasts longer. When there is no wire, the starter will not arc over, and therefore will not turn. Is that what you are talking about kind of?

Frayed knot; my OT (this is a twin screw thread) was about eliminating car "stereo" noise.

Thanks, Bill!

Just comparing a digital gauge with my Analog. The digital boost gauge was VERY SLOW to react. In this picture you can see the lag...Fuel pressure reacts a bit quicker but not like my electric analog.

Hi Tony,

You have talented feet! :-)

Did the digitial "catch up" with the analog? Or did they read different levels altogether?

These are some pics of the Oil breather system in Dariens car. It uses my 1" copper pipe starting from a seperator on top of the oil filler neck (out of view)..it leads out then up across the passenger side cam cover where it picks up the two vents threre. It then makes a 180 at the end wher it comes back to the front of the car and enters the seperator which BTW fits perfectly under he 86.5 throttle bracket. From there the line is sent down by the front passenger side wheel well area where it dumps to the air. You can also dump it to the exhaus stream and actually, with the quality of the seperator, i think you could dump it right back into the intake track with out much worry.

Very nice, clean and logical setup! Does the separator dumps the oil back into the engine or it require periodical draining?

Well, i used to be a prety damn good soccer player and the female skeletons in my closet would say ... :D

When i finally opened my eyes :eek: , the gauge did appear to catch up, but it was a off compared to the anaolg i think, ...whos to say which one was right though? Id lean towards my analog as i have had running with my data logger and it is pretty close. Granted it doesnt accurately read the "POINTS" like a digital would, but it gives a quick easy representation of whats happening. This car, Dariens,acclerating as fast as it frikn does, you really dont have time to look several times or wait for a boost gauge to respond. Eyes out front. The one i use is BAM, right there instantly. BTW, that is the smaller pulley. :rockon:

DR, the digital will catch up, but I was amazed how slooow it is compared to analog:( Looks like I'll be replacing them in the future.

Nice pic's Tony :rockon: