WIring/CIS problem on retrofit Paul/Jim?

Elombard · 12-17-2004, 06:04 PM

Hi guys

Hopefully an easy one.

I have a 73.5 T that came with a 78 SC motor with CIS. Ran perfect when I got it 3 years ago. I ended up changing this motor out for a 79 euro CIS motor. I dont have the factory manuals but pretty much everything else. As the wheather has become colder I have had starting/idling problems that I have traced to no voltage to the WUR and AAR. they have continuity to ground and to the #10 pin in the 14 pin connector on the engine harness. The #10 female on the chassis has continuity with the red/white on the 3 fuse panel. When the car is running the red/white has 12v. When the car is running the AAR/WUR have no voltage???

The wiring diagram for a 74 shows a relay in the WUR circuit. On the 73.5 there is no relay but it goes through a solenoid switch.

I think the rear relay panel has been switched out to a 78 - not sure.

Do you have any idea how I can get power to #10 in the 14 pin or why I am not getting it. There must be something between the 3 fuse panel and the 14 pin chassis (rear) connector but I cant see it.

Thanks for any help

cmonref · 12-18-2004, 07:09 AM

The '78 wiring diagram shows the red/white connected to a fuse on the rear fuse box is not the same red/white that powers the WUR/AAR -- it serves the heater blower on the engine.

Your red/white comes directly from the fuel pump relay to the #10 pin on the engine harness. The '78 wiring diagram shows a 1-pin terminal connection "behind the [main] fuse panel". Have you done some work there that may have inadvertently disconnected that terminal fitting?

If your rear fuse panel has been replaced with a '78 panel, maybe a non-factory splice has separated. With a little care, you can remove the cap screws that hold the fuse panel to the left sidewall and move it around a little to expose the spaghetti behind the panel.

In the process, maybe you can demount the 14-pin receptacle from the panel and expose the wires behind. Maybe the connection has pulled loose behind, or corroded badly.

Wishing you lotsa patience ...

Elombard · 12-18-2004, 10:14 AM

Thanks Brian. It must be something like that. The 73 does not have a fuel pump relay so its very confusing for me. I should have looked closely at the old wiring harness before I sold it. I guess I will pull the panel and look around. I am about ready to just find an appropriate 12v source and replace the wire in there so I get 12 with the key on. I just hate to mess up a harness and confuse a future owner or his mechanic!!

cmonref · 12-18-2004, 06:51 PM

You note that the '73 did not have a fuel pump relay. The factory manual for a 73.5T shows a solenoid switch (a relay by another name) that is apparently located on the engine fuse panel.

In the factory manual, a supplement to the wiring diagram for a 73.5T with CIS shows that the rear fuse panel provides power to the WUR. A red/black wire from fuse 2 goes to terminal 30 of the solenoid switch. The switch'e terminal 87 feeds power thru a red/white wire to the WUR via terminal 10 on the 14-pin.

So this supplement changes what is on the wiring diagram. The riginal wiring diagram shows the red/white wire from fuse 2 wired directly to the WUR thru terminal 10 of the 14-pin. The supplement says that this red/white wire "has no function in K-Jetronic equipped vehicles even though it continues to be installed for production purposes."

Maybe this matches what you see on your car?

cmonref · 12-18-2004, 07:06 PM

To clarify the rear fuse panel on the 73.5T. Here is a description of the fuse's wiring.

One side's wires Fuse Other side's wires
green/yellow # 1 red #1 and #2 are
red/white # 2 red/black jumped together
red/black # 3 red

The red/black that goes to the solenoid switch is from fuse #2 -- the middle one.

The red wire on fuse #1 comes from the voltage regulator, providing power when the alternator is actually producing power. This means that fuse #2 has 12v only when the engine is running, not when the ignition switch is on.

Still wishing you patience ...

cmonref · 12-18-2004, 07:11 PM

MY attempt to show the wires and fuses did not work. I'll try again:

One side's wires----->fuses<------other side's wires
green/yellow--------->#1<---------red-----------#1 and #2 are
red/white------------->#2<---------red/black----jumped together
red/black------------->#3<---------red

The "jumped together" means that the the red and red/black sides of #1 and #2 have a jumper wire connecting them.

Elombard · 12-18-2004, 08:03 PM

Interesting.

Thanks for looking at this, you have cleared up alot of questions I did not even no I had. I thought the solenoid in the wiring diagram was starter related - that clears up alot. I believe the 73 fuse panel is still in the car

Here is what I did today to resolve the problem.

I pulled the fuse panel off and traced wires around and discovered that the red/white from the #10 (WUR) went through the relay you mention. I discovered that the black wire from the relay you mention was cut, so I connected it. This had no effect.

Some background, this car had an internally regulated alternator when I got it. The new motor did not. There was some wiring mischief as a result of that change by the PO...if that gives you any clues.

Next I discovered the relay had no effect on the car starting or running so I opened it up and "gutted" it. Then I made a jumper so the power goes to the red/white and out #10 to the WUR when the key is on. Problem solved! (or so I thought)

I thought at this point I had the SC fuse panel and that this was the fuel pump relay which was not used. Now I wonder what other effects I am going to have :-)) Oh well I can just change the relay if its a problem.

It looks like the relay engages the voltage regulator, I bet my alternator light is on now. I did not notice.

DO you know what the black wire does?? It shows going to the voltage regulator but the car has been charging fine since I plugged the regulator back in to the system and the black wire was cut?
With out the realy will I burn up the voltage regulators?

I dont think this issue is because of a bad relay because I switched them around several times.

cmonref · 12-19-2004, 08:07 AM

The terminals of the solenoid switch are connected like this (according to the supplement to the manual).

Term #30, red/black, from fuse #2 as stated above.
Term #87, red/white, to the WUR
Term #85, brown, to voltage regulator terminal D- (ground)
Term #86, black, to voltage regulator terminal D+/61.
Term #87a is not used

Terms 85 and 86 provide the switching of the relay. That's how the alternator "switches" the WUR power ON. Check #85 (the brown wire) continuity to ground. #86 (black wire) should have 12v with the engine running.\
From this, I would surmise that cutting the black wire should have no effect on the alternator. Is should be a sensing wire, not a functional wire that would "engage" the alternator.

The supplement says that the WUR is switched from the alternator to prevent continuous power from being applied if the ignition is ON and the engine is not running. The SC series CIS fuel pump and WUR/AAV are switched through the red fuel pump relay to accomplish the same thing, except it switches that stuff ON when there is air passing through the fuel distributor.

You've got some real sleuthing to do -- but you knew that already. No telling what the PO did while going from an internal regulator to and external one -- or something like that. Cutting the black wire was only one of the things that were done.

What color of wire connects to term #30 of the relay? According to the supplement, it should be red/black, coming from fuse #2 as stated earlier.

Fuses #1 and #2 should have 12v with the ignition ON.

Elombard · 12-19-2004, 11:03 AM

I see

So all that relay does is turn power on to the WUR when the engine is running. Very slick. So technically my surgery and hard wiring of the WUR to come on when the key is on wont effect anything. I am not sure how you could turn the key on and leave it on, the fuel pump runs and drives you crazy!! That expalins why removing the relay apeared to have no effect on the cars operation.

The wire colors connecting the relay are correct and ....you know what I just realized there is no jumper from fuse 1 to 2. At least not externally. I guess it could be underneath. Fuse #1 and 2 have power when the key is on....fuse 1 has power all of the time (I have acidently sparked a screw driver a few times)??? This must be one of the wiring compromises that are made when you install the later SC motor in an early body. There is a red wire that runs to fuse #1 that was definitley added. It comes from the engine harness. Odd though if 1 and 2 are jumpered they should both have power all the time! they definitely do not. Hmmm. let me poke around a little.

cmonref · 12-19-2004, 12:45 PM

In the 73.5T, fuse #1 in the engine compartment was ON with ignition ON. the green/yellow wire went to the (optional) Sportomatic gear lever contact.

If someone rewired the fuse #1 output, they probably also removed the jumper between #1 and #2.

Jim Sims · 12-20-2004, 06:56 PM

EW, Did you come to "closure" on this? Jim Sims

Elombard · 12-20-2004, 07:08 PM

Hi Jim

Yes and no. By making a jumper for the relay I have a fine running car. I still wonder how they had the old motor working and why I could not get 12v through the relay for the new motor?? There must have been some creative wiring by the POs mechanic when he put the internally regulated alternator in.... other than the clipped black wire i could not see anything obvious. It must have been in the way he moved pins around in the 14 pin.

Thanks