cd box failure?

rick conrath · 03-29-2003, 01:03 PM

Went for a fun run today...and my car died halfway out. What I noticed was that the cd box was not humming with the key in the on position. After about an hour...the box started to humm again and the car started right up. Let the car idle for 15 minutes and the car would die again after warming up (no humming from cd box) Is this a bad cd box or a bad relay that is responding to the heat?
If the cd box is bad...I am thinking of an MSD unit.Opinions?
thanks,
Rick '78 930

tryan · 03-29-2003, 01:36 PM

there is a cd box thead on early s. you might pick a spare up. the word rebuildable comes up, but in my hands that my mean something else.

check your power supply and search supermans threads. ( ie relay under passenger seat )

rrcrawford70s · 03-29-2003, 02:10 PM

I have a 1970 S. I had the same thing happen to me.
Check the ground. The braided wire attaching to the clip on the CD Box to the body. Check all GROUNDING points.

If you have to rebuild, call our host for the exchange.

rick conrath · 03-29-2003, 02:37 PM

I thought ground at first....but it dies after heating up, or running for awhile. I will check connections.

RoninLB · 03-29-2003, 02:40 PM

Quote:

Originally posted by rick conrath
I thought ground at first....but it dies after heating up, or running for awhile. I will check connections.

when it's dead check positive at the box

pwd72s · 03-29-2003, 05:15 PM

Quote:

Originally posted by rrcrawford70s
I have a 1970 S. I had the same thing happen to me.
Check the ground. The braided wire attaching to the clip on the CD Box to the body. Check all GROUNDING points.

If you have to rebuild, call our host for the exchange.

Hmmm. Does this mean our host sells rebuilt 3 pin units? I could buy one outright? Please don't say search the catalog...I have a hard time negotiating on line catalogs.

Early_S_Man · 03-29-2003, 05:24 PM

Yes, Paul, thet do ... but, STRANGELY, they aren't in the '65 - '73 catalog!!!

CD Unit, Rebuilt, 911 (1974-77) [Photo]
A-602-702-00R $225.00

rick conrath · 03-29-2003, 05:45 PM

You are referring to positive going into the box I assume. I will have to move a bunch of stuff to see where that is. Intercooler, etc. It makes sense to me that this intermittent behaviour, is due to the effect of years of heat from my turbo on the box. I can only assume that this is the original box('78 vintage), so it's probably seen better days. If there is no power going to the box when it dies, then it's a hunt for a short going back to the fuse panel?

rick conrath · 03-29-2003, 05:46 PM

What about the MSD units.....?

RoninLB · 03-29-2003, 06:06 PM

"You are referring to positive going into the box I assume."
--- Yes.. I'd probably rig some kind of a test wire to the positive so I could check it quickly.. then attack other stuff while the unit is kaput

" It makes sense to me that this intermittent behaviour, is due to the effect of years of heat from my turbo on the box."
--- yep.. probably correct.. do you want to bet big bucks before other things are eliminated.. although I always carry a spare CD and coil..
and for instance, is your ignition switch original?

" I can only assume that this is the original box('78 vintage), so it's probably seen better days."
--- maybe you can borrow a friends

" If there is no power going to the box when it dies, then it's a hunt for a short going back to the fuse panel?"
--- probably not a short

red-beard · red-beard's Garage

I have 2 working CD boxes (used) if someone is looking for one.

PM me for details

James

rick conrath · 03-29-2003, 06:24 PM

Thanks. I would bet that the box is heating up and failing after idling. It was running fine in the driveway just sitting (you could hear the whine from the box). Just as the engine compartment started to get warm, it shut off (no whine, nothing...). I don't think its a short.

pwd72s · 03-29-2003, 07:11 PM

Quote:

Originally posted by Early_S_Man
Yes, Paul, thet do ... but, STRANGELY, they aren't in the '65 - '73 catalog!!!

CD Unit, Rebuilt, 911 (1974-77) [Photo]
A-602-702-00R $225.00

Thanks Warren! Good point, why the hell would I click to look for 1974 and up parts????

dean · 03-29-2003, 07:15 PM

I put an MSD6-AL in my car. It works fine. It is harder to install than the stock unit but it is cheaper if you put the time in for instalation

RoninLB · 03-29-2003, 07:16 PM

Quote:

Originally posted by pwd72s
why the hell would I click to look for 1974 and up parts????

doesn"t the '74-'77 CD fit your car?...LOL ...............Ron

pwd72s · 03-29-2003, 07:19 PM

Quote:

Originally posted by rick conrath
What about the MSD units.....?

I hate to be the guy to say this, but do a search..here and on Rennlist as well. Lots of guys seem to be very happy with MSD, if it's done right. Possibly functions better than the factory unit, assuming the right wires, coil, etc. are used.

pwd72s · 03-29-2003, 07:21 PM

Quote:

Originally posted by RoninLB
doesn"t the '74-'77 CD fit your car?...LOL ...............Ron

HOOT! Something about the number of pins? Besides, I dunno if I like the bigger bumpers they put on the '74 CD boxes...

rick conrath · 03-30-2003, 03:46 AM

Yes...I see that some have been happy. Was not sure about the turbo application though. I know it worked great in my 67S.
Thanks,
Rick '78 930

Rouxzy · 03-30-2003, 04:48 AM

I just installed the msd in my '77 with big noticeable improvements. My cd box worked but had NO whine for the past two years. Go figure. When mine heated up as in real hot weather the car would lack power, it would run but more like lack luster.
Tom

Halm · 03-30-2003, 05:01 AM

Purely in the FWIW catagoy, Otto (Otto's Venice) hates MSD units. When he was preparing my '70 E to drive from LA to Charlotte, NC last year he removed a MSD unit and replaced it with a stock CD system.