Casual_John

iTrader: (8)

I am seeking photographic clarification of the wires and connectors outlined in the FC parts manual, section 6684-1, as shown in the attachment. The sketch is too vague for me to resolve my issue. I'm having intermittent radio reception problems.
RX7 FC S4 6684-1 Noise Suppression and Ground Cord - Audio Systems.pdf

(And could someone repost this PDF attachment as a JPG image, somehow, please.)

Casual_John

iTrader: (8)

So, I believe there is supposed to be a connector from the left side strut tower to the starter motor, right?

And a connector from the left muffler to the chassis?

And from the top of the clutch cover/transmission to...the firewall?

Does anyone actually still have these in place? I hope so.

Prove it with pictures.

FührerTüner

iTrader: (5)

jjwalker

It's talking about the Oil pressure sending unit condenser (capacitor) and the ground strap for the exhaust.

Ignore the ground strap for the exhaust because it's useless.

The condenser for the oil pressure gauge is just to smooth the voltage coming from the sending unit and has nothing to do with radio reception.

First of all, are you using an aftermarket radio? Did you do the appropriate relay mod for the powered antenna?

I ditched my power antenna and made an adaptor to use the antenna in the windshield. The windshield antenna actually works better than the mast antenna.

Casual_John

iTrader: (8)

Thanks for the image, Fuhnortoner.

JJ, I am totally oem...stock radio, cassette, speakers and retractable power antenna. Since I have all the stock components, I should be able to trust the shop manual for a solution, I figure.

I noticed the problem since my engine rebuild. Maybe the installer missed a ground somewhere. I just don't know what they all are suppose to look like.

By intermittent problem, I mean the radio reception can be fine initially when I start the car and drive a bit, but as it warms up, it cuts out and gets quiet and staticy. It rarely recovers while i'm driving. I don't thing it is related to a bump or bounce. It seems to be impacted my a warmed up engine...strange.

jjwalker

I have seen so many FC's and FD's with radio issues in my career after engine rebuilds and I still haven't been able to figure out what they are doing to cause the issue. My belief is the engine ground doesnt get torqued correctly and it gets loose. I recently fixed an FD with the same issue by pulling the radio out and re-grounding the radio harness to the metal dash support. I have fixed FC's before by running a new ground to the driver side kick panel area.

The engine ground for the S4 is a complete bitch to get to as it is under the intake manifold, but I bet it has worked its way loose. As the engine heats up, the nut will loosen itself. You will need to pull the intake manifold and make sure that sucker is tight. If the engine ground is marginal or bad, the ignition system noise will interfere with the radio. During the trouble of taking the intake manifold off to get to that grounding location, I would move it to a more accessible location for the future.

It doesn't hurt to upgrade your engine and chassis ground either while you're at it. The stock FC grounds suck and I dont really know as an automotive technician what the hell mazda engineers where thinking but, you can easily improve the chassis grounds. Running a 8 or 10 gauge wire from the stock engine ground to the passenger side firewall will help with ECU and sensor grounds. As far as chassis grounds, run an 8 gauge wire from the negative battery terminal to the driver side shock tower where the fuse block bolts in. The factory chassis ground is bolted on the bottom of the shock tower but suffers from corrosion due to it being exposed to water.

Casual_John

iTrader: (8)

Yes, I am aware of that. I'm hoping not to go there. That's why I want to verify the other noise suppressor points first.
Thanks

Casual_John

iTrader: (8)

I believe this is a connection point on the firewall, for FB01-55-970 to attach to, from the top of the transmission. What else could this be used for?

jjwalker

John, PM me your number and I will call you and walk you through this.

Casual_John

iTrader: (8)

Or does the lead, from the top of the tranny connect to a point on the right strut tower?

jjwalker

I PM'd, you could just call me :P

There is supposed to be a ground going from the top of the transmission to that ground point you posted in that picture. It usually breaks off during removal but you can reground that to the passenger side bolt of the slave cylinder without any issue.

Casual_John

iTrader: (8)

ok, thanks. Now I finally know why that thing is on the firewall. It IS a ground. And it SHOULD go to the transmission.

I knew I could count on southern hospitality to help me out.

It's much too cold for me to actually work on this in January. And the car is in storage for now. But I figured a southern guy would have better access under the hood, without a coat and gloves on.

misterstyx69

iTrader: (142)

all that crap is either for Oil pressure (smooths out signal to the sender) or ground (straps from the exhaust and the trans to firewall).
It has Zilch to do with the Stereo.
Have you tried a Radio shack suppressor in between the positive of the stereo to the feed of the harness?.That would be the easiest thing to do.
Another thing to try would be a another ground attached the stereo to say the Floor,or even the bolt that holds the dash to the hump on the floor(under the triangular plastics..on each side of the dash)

IF You really get frustrated John,I got like 3 decks here..all aftermarket you can take your pick..free.