No noise from CD box
 

I finished the rebuild - then had to perform partial drop to correct leaks. Before the drop I heard the sound of the CD box -- now I don't. I checked the connection at the box and it is on . . thoughts?

You didn't drop the CDI unit from six or eight feet onto hard concrete, did you???

I can tell you positively that your CDI didn't 'die' while you were working on the engine ... I am quiye certain they don't suffer from 'parking lot death syndrome' like many Ford ignition modules did during the '80s and '90s!

If it was working before and all you did was an engine R&R ... then you don't have good continuity somewhere in your electrical system, now! Your challenge is to find thge problem with one or more ground straps, or the 14-pin connector, etc.

Unless you have verified the precense of 12 Volts at the connector terminal #15 of the CDI unit itself ... then you HAVEN'T 'checked the connections!!!' You may need to build an extension cable of six wires, six male 1/4" Fastons, and six female Fastons ... but don't ASSUME your CDI is bad until you have verified good grounds at terminal #31/1 and #31d, and good power at terminal #15!

http://forums.pelicanparts.com/porsche-911-technical-forum/158541-ignition-troubleshooting.html

I turned the ignition on and used a wire tested and I'm not seeing a charge at the red wire on the six pin. I'm not seeing light on the green wire connected to the distributer. Will a regular wire tester work here?

I just noticed the brown connecter on the end of the signal wire is cracked. Is this repairable? at least enough to see if this is the problem can I bypass the connector, safely?

If you lose ground at the grounding post behind the fuel accumulator...the CD box will not run. Check your voltage to the unit.
Rick
'78 930

There is ground behind the accumlator??? I'll check that. I'm not getting voltage to the unit. I had to reach my arms in the back of the engine to attach crankcase breather hose -- Is there any electrical back there that would cause this?

There is a large terminal behind the fuel filter and accumulator which acts as the grounding post for about 5 to 6 grounding wires.....impossible to really service without taking out the filter. The brass rings on the grounding wires will build up corrosion with time. Sometime you will get voltage to the CD box but as the engine warms up, you get resisitance at the connection to the point where the voltage drops.
Rick
'78 930

Ok, I've tested the following wires.

With ignition off
number 14 pin (from wiring harness) -- hot
no others are hot

With ignition on

fuse block hot 1 -2
red pin on cd connector is not

It doesn't seem to be an issue from the front -- the problem seems to be between the 14 pin connection and the cd Box

Would the trigger wire cause this?

No. It is only an input signal to terminals #7 and #31d ... AC waveform.

If the green coax coming out of the distributor or its' connector is discolored or damaged, it should be replaced, it's only atround $26 from Pelican.

Here is the relevant wiring ...

http://www.pelicanparts.com/ultimate...hematic-1s.jpg

Does your car have a factory alarm system? If so, the following thread may be instructive:

http://forums.pelicanparts.com/showthread.php?s=&threadid=59329&highlight=wont+ru n

with ignition switch on what is your reading on cd box connector supplying power to the CDI box...I think pin #15? If it's not 12 volts the CDI box will not work.

Rick
'78 930

Thanks for the diagram -- Rick, I only have a tester light and it does not light on any of the pins. I think I will go buy a voltmeter in a little bit.

The voltmeter would be good. That way you could check to see if you are getting any voltage tothe box.
Rick
'78 930.

Radio Shack (yecch) actually sells a little digital one for about $25. Cheap and pretty good. fits in a pocket. Great for travel and occasional use.

No Fluke, but a great add to any non sparkies toolbox.

New wrinkle -- went to radio shack and bought the tester, the six pin CD box connection (red wire) is showing 11.6v. to check the grounds where are 31/1 and 31/d are the terminals on the cd unit?

Scratch that -- I'm only reading .6 volts from the 15 terminal -- Does the source come from the engine harness. I'm assuming so. At this point, I guess it is time to cut the black tape off and trace all the way back.

It just started though, the CD box whined right before the partial drop. Am I missing someting easy?

I checked the
transmission strap
All of the starter wires

According to the schematic wire 15 connects to fuse 17 ( i think the schematic is in the garage). Is this in the fuse box or somewhere else on the car?

It has been a year, I'm really looking forward to driving this car HELP?????

The Terminal #15 switched power wire comes from the ignition switch, via a 6-pin connector and bus junction at fuse location #12 ... power into junction is Red/Black wire, and out & back to engine it is Red.

http://www.pelicanparts.com/911/911_...SC_Part3-2.jpg

Please confirm that you have good ground as I previously described. I too only had .6v at #15 until I cleaned up tye terminals at the grounding post. Car started right up afterwards. You might have a break/short in the harness.
Rick
'78 930

Thanks guys -- I'll start again in the morning

Through pure genious, hard work and dedication, I fixed it -- it was th friggin fuse.

New problem, still won't start, I pulled the injector did not see (I disconnected it at the two nuts) fuel ejecting. I do smell fuel. The car sat for a year. Thoughts

<b> I fixed it -- it was th friggin fuse.</b>


What do you mean???

-- the CDI isn't fused anywhere in the car!!!