Getting my 81 911SC back on the road

[Kool-aid-82]

So I have taken my 81 911SC out of storage and am working to get it back on the road. I have owned the car since 1985 and am the second owner. So any issues it has are my fault… It was a daily driver until 1994 and has 132,000 miles and I rebuilt the engine back in 1990 at about 128,000

It has been stored “pickled” since 1998. Life and kids take a lot of time.

I have basic mechanical skills and have already replaced the fluids, Cleaned the tank, Filters and Rebuilt the brake calipers, new lines, rotors and pads packed the bearings. Replaced the Plugs, Wires, Cap and Rotor while I was at it. (Pelican is a an amazing resource for information and parts)

New tires are on order, and I have been chasing CIS gremlins while I was waiting. I did have to replace the fuel pump but have been just checking the other components as a precaution.

Anyway, today was a slow day and while I waited I thought I would fix an old issue. Back in 1991 The fuel pump fuse holder became loose and I was forced to improvise in the field. I had to move the wires over one terminal and left myself a note for reference.


21 year old reminder

So today I thought I would fix this issue by installing a new fuse panel. (I had purchase parts in the past (199?) and had them on the self.


New Old Stock...

I took each wire individually off and put it back on the new panel, taking pictures as I went for insurance.


1989 Rewire


2012 Rewire - New Fuse Panel

But now after hooking everything up I no longer have power to my fuel pump relay?
Jumping 12v to Term 30 runs the FP.
But no power at any terminal in any ignition position.
Somebody tell me these fuse panel have no internal wiring and this is a simple swap out.

What am I missing.

[jeffs9146]

I don't see the larger red wire from the last fuse that is in the before photo but not in the top space of #6 in the after photo?? And the green and blue wire that was your jumper wire is not in the bottom of #6 slot! It is in the bottom of the #7 slot. Where in your before photo it is in the last spot!

[Kool-aid-82]

Jeffs9146
The large red wire moved back to top of the #4 fuse
Large green wire was a "fix" to get the Green w/Blue stripe and Black wire from the bottom of #4 to the bottom of #8 this large green wire was removed and GRN/BLE & BLK wires are now on hte bottom of #4.

FYI
There is some internal conection going on behinde the panel, but I used the correct panel as a replacment.
Verification photo.


Pulled the tops back off to verify.

Still no power to Fuel Pump Relay & Still looking...

[Kool-aid-82]

This time with the picture



Backside of Fuse Panel

Break is in the top panel but the flash covers it up...

[Kool-aid-82]

OK, after thinking about this all night I have concluded that the problem was not what I did yesterday. But what I did 21 years ago. The fuel pump was not running and I thought it was the fault of the bad connection on the fuse panel.


Olf Fix reviewed

This got the car running but did not address the root problem It just supplied power to th FP.


Bad assumption

Backside Bridge

So back to searching,
The system worked prior to installing the new Fuse panel.
I can jump term #30 to power and the FP runs.
But have no power at the relay.

How do I trouble shoot this?

[jeffs9146]

I can't keep track of your numbering system!!? When you say #4 you have #6 boxed in on the front side photo????

[Kool-aid-82]

Sorry ,
I am refering to the number of the fuse panel slot.
There are 3 Fuse panels on the car.
From left to right on my photo...
First has 3 slots numbered 1-3
Second (the one I replaced) has 10 Slots, numbered 1-10
third has 8 slots, numbered 1-8

So my Fuel Pump fuse is on the second Fuse Panel Slot #3

[Jdub]

Sorry not to be of help with the wiring, but would very much advise that you replace all of your old fuses with new ones, being sure to cross-check that the correct fuse rate is being used at each position. Empty positions should be used to store extra fuses.

Blister packs of the red, blue, white, etc. can be found at Pelican.

[BMWonly]

Make sure to use ceramic 25A fuses, they can get pretty hot and the plastic ones can melt (especially the A/C fuse).

[Tremelune]

If you're not worried about originality, use a blade-type fuse panel. They are superior in every way.

Edit: I guess you already got the panel in...Probably not worth it at this point...

[Kool-aid-82]

Thanks, Got the fuse panel back in but stil no power to relay.
Reading through the CIS Pimer, I see
"Relay Connections:
The fuel pump is connected to pin 30 of the relay socket. (Note that you can't jumper power to the fuel pump by jumpering +12 Volts to a fuse on the fuse panel. The fuse which protects the fuel pump is in the wiring that goes from the NC contact to the ignition switch)."

where is this fuse?

[boyt911sc]

Originally Posted by Kool-aid-82

Thanks, Got the fuse panel back in but stil no power to relay.
Reading through the CIS Pimer, I see
"Relay Connections:
The fuel pump is connected to pin 30 of the relay socket. (Note that you can't jumper power to the fuel pump by jumpering +12 Volts to a fuse on the fuse panel. The fuse which protects the fuel pump is in the wiring that goes from the NC contact to the ignition switch)."

where is this fuse?

Kool,

To test run your FP using the FP relay socket, just follow this basic procedure:

Condition #1:
Ignition switch @ OFF position (FP relay removed).
87a..........no power
86............no power (note: 87a and 86 are bridged at the socket side).
87............no power
85............presence of ground contact.
30............no power, but has ground reading

Condition #2:
Ignition switch @ ON position (not start).
87a...........has power
86.............has power
87.............no power
85.............presence of ground contact
30.............no power, but has ground reading.

The difference between these 2 conditions are the presence of power at terminals 87a & 86. If you could satisfy these conditions, the wiring connections at the FP relay is on par. If you don't get the power expected to be present at these terminals when the ignition switch is @ ON, the problem is the power supply. Either the fuse is not allowing current to pass thru or the ignition switch is not supplying the voltage. These are easy to check. And I'll give you more detail procedure to locate the problem. But you have to be systematic in looking for the culprit/s. Keep us posted.

Tony

[Kool-aid-82]

Boyt,
Thanks I have defined the following;

Condition #1:
Ignition switch @ OFF position (FP relay removed).
87a..........no power -True
86............no power (note: 87a and 86 are bridged at the socket side). - Ture
87............no power- True / 87 & 85 are bridged
85............presence of ground contact. - True also 87
30............no power, but has ground reading - True

Condition #2:
Ignition switch @ ON position (not start).
87a...........has power - No Power
86.............has power - No Power
87.............no power - True / but has ground reading
85.............presence of ground contact - True
30.............no power, but has ground reading - True

I am thinking Ingnition Switch, what do you think?

[timmy2]

Kool-Aid-82
1. With ignition switch in on position, do you have power to the top of fuses 11 thru 15?
If there is power there, the switch is working.

2. Is there a red wire jumper from the top of fuse terminal 11 to the top of fuse terminal 16?
If not, you have wired your fuse block incorrectly.

Download the '78 diagram and the '82 diagrams, print them and figure them out. The light lines between the S (fuses symbol) on the '78 print are the connectors on the back of the fuse panel. Once you figure out what everything is and where it goes,Then start wire checking/tracing.

Pelican Parts - Porsche 911 Parts Listings & Diagrams

This will help:
http://www.thesamba.com/vw/archives/info/wiring/Understanding_Euro_Wiring_Diagrams_Motor_Magazine_ April_2003.pdf

I am an electrical technician by trade and will answer any questions you have. You can PM me anytime. (I've trained a lot of apprentices over the past 25 years!)
I've even helped a few members on the phone with troubleshooting their electrical systems.

Good luck and keep posting your results.

[timmy2]

My version of a good electrical print!
Kinda big, but easy to read...

[timmy2]

My car looked a lot like yours in the wiring department when I bought it.
With a bit of work mine now looks a lot better and works as designed.
Notice the wire markers from tracing and removing all wires.
Who am I trying to kid, it was a lot of tedious work....
Heck, there is even a headlight relay kit wired in there somewhere...
(Ignore the stuff on fuse 1, my custom wiring for some extras...)

[Kool-aid-82]

Dennis,
Thanks for the reply and offer.
That is one of the things that makes this forum so great.

I feel confident with a wrench but wires and charts confound me.
I have been looking over the current flow diagrams for my car and am slightly lost.


1981 Fuel Pump

But the Answers to your questions:

1. With ignition switch in on position, do you have power to the top of fuses 11 thru 15?
If there is power there, the switch is working. True

2. Is there a red wire jumper from the top of fuse terminal 11 to the top of fuse terminal 16?
If not, you have wired your fuse block incorrectly.
No - See Picture below for clarification



For clarity I have Numbered the fuses.
I must have wired the box wrong by jumping this to #1 21 years ago...
The pump ran because of the backside bridge

Current flow shows Red on Red as well


Curious what does the #17 and the 2 in the circle stand for on the other end of this run?

Thanks again for your help

[Kool-aid-82]

Pictures of #17???

[timmy2]

The 2 is a ground lug point, probably some others running to that location.
The red wire coming out the top of 16 is marked 15 at the end of the page, The next page carries it on for a couple of pages (marked path 15) until it goes to fuse 11.

Print out all of the pages and line them up side by side, then you can follow it better.(All will become clear)
The original prints were "fold out".

From your fuse panel picture, try the following:
Remove the red wire from top of fuse 15, put a piece of electrical tape on the bare conductor, test for power on 11 to 15 again.
If you have power, then connect the removed wire end from fuse 15 to the top of fuse 16 and see if your fuel pump runs normally.
Diagram shows red on top and bottom of 16 as you stated, there's a red coming off the bottom, nothing coming in the top.

[boyt911sc]

Originally Posted by Kool-aid-82

Boyt,
Thanks I have defined the following;

Condition #1:
Ignition switch @ OFF position (FP relay removed).
87a..........no power -True
86............no power (note: 87a and 86 are bridged at the socket side). - Ture
87............no power- True / 87 & 85 are bridged
85............presence of ground contact. - True also 87
30............no power, but has ground reading - True

Condition #2:
Ignition switch @ ON position (not start).
87a...........has power - No Power
86.............has power - No Power
87.............no power - True / but has ground reading
85.............presence of ground contact - True
30.............no power, but has ground reading - True

I am thinking Ingnition Switch, what do you think?

By just looking at the data you have collected, it is obvious that the problem is the power supply side. There is no power getting to terminals 87a & 86 at the FP relay socket. You could not even test the FP using these terminals. So the big question is why? The answer is very simple. What reference manual do you have? A Bentley or factory shop manual?

I'm away from home baby sitting my one-year grandson and when I get home tonight, I'll lay out a simple procedure to detect where the missing link is happening. Relax, the problem is easy to fix and you could do it!!!!!! There are plenty of help available in this forum. How do you test for power? Test light or VoM! Or something else?

Terminals 87 and 85 are not bridged!!!!!!! Double check it. Terminal #87 is the terminal with yellow wire going to the starter's solenoid and CSV. While terminal #85 is the ground contact for the relay coil at the AFS switch. Keep us posted.

Tony