# Troubleshooting CIS issues 1981 Scirocco



## rjohns1 (Aug 9, 2006)

Alright, the background: I just bought a 1981 Scirocco. Engine was swapped toa JH 1.8L motor, solid lifter head. previous owner put what looks to be a CIS-Basic fuel distributor. I have an O2 sensor though, so my frequency valve is missing. The wiring is butchered. I have a Bentley manual, I got the one for 1980 and 1981 Scirocco, Cabrio, Rabbit, and Pickup. The wiring diagrams are not detailed enough, as it does not mention the frequency valve. So here is what I am finding. 
Idle is really low cold, we are talking 300 to 500 RPM. Stumbles on acceleration just enough to be annoying. When it warms up, idle is about 900 to 1200, and runs pretty good. The car smells rich all the time though. 
The plug has already been drilled on the fuel distributor. i followed these instructions, and got it to run this way with this: http://merlyyn.com/tech/. 
I bought some spare parts from a local guy who is carbing his 1982 Rabbit Cabrio. I got a cold start injector, two idle air control valves, another temp switch (The CIS one, not the gauge sender), extra edu, and harness, and some boots for the intake. I have swapped out some parts, O2 sensor is brand new, and the condition has not changed. I decided to test the cold start valves by using one that is not installed on the car, by hooking up the fuel line, and electrical connector. Car was cold, and no fuel sprayed. I finally did some digging, and found that it is looking like I have no power at the Lamda controller under the glovebox. I found that power is supposed to come from the fuse panel, from a control relay, and the wire is green with yellow stripe, other wire in the two pin connector is red, maybe with a stripe. It runs to the fusebox, so this harness is power. I have nothing. 
So, I believe first order of business is to get the wiring diagram for this control unit. I've looked online, and have not found any. I found this site with pinout:http://www.a2resource.com/electrical/management/jetronic.html , but is doesn't tell which pin is number one, so it is not very helpful at this point. 
Also, According to the Bentley, the O2 system relay, is the one furthest to the right on top. The socket has more than four pins, but the relay is just a tall 4 pin relay, and it does nothing. 
So, Here is what I am looking for. A link to an actual diagram for the wiring. CAn I give this ECU 12v on that green wire? Does this relay just turn the system on with ignition? I need to get this powered up to start troubleshooting, and figure out what I have, as I can't verify what the car has in it. ANY help from anyone here is mucho appreciated, and I thank you all in advance. I want to restore this car, and want to keep it the way it came.


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## kamzcab86 (Feb 14, 2002)

rjohns1 said:


> a CIS-Basic fuel distributor. I have an O2 sensor though, so my frequency valve is missing.


 You have a CIS-lambda car that has been, partially, turned into a CIS-basic car (or a PO was attempting to take a CIS-basic car and turn it into a CIS-lambda car and didn't complete the job). Unplug the O2 sensor and everything related to it and see what happens... or get a fuel distributor with a frequency valve. 



rjohns1 said:


> The wiring is butchered. I have a Bentley manual, I got the one for 1980 and 1981 Scirocco, Cabrio, Rabbit, and Pickup. The wiring diagrams are not detailed enough, as it does not mention the frequency valve.


 The frequency valve is located right off the fuel distributor, if your car still had it. It's electrical signals come from the Jetronic ECU (pin 15) via a brown/blue wire and from the power supply (lambda) relay via a red/yellow wire. 



rjohns1 said:


> I finally did some digging, and found that it is looking like I have no power at the Lamda controller under the glovebox. I found that power is supposed to come from the fuse panel, from a control relay, and the wire is green with yellow stripe, other wire in the two pin connector is red, maybe with a stripe. It runs to the fusebox, so this harness is power. I have nothing.
> So, I believe first order of business is to get the wiring diagram for this control unit. I've looked online, and have not found any. I found this site with pinout:http://www.a2resource.com/electrical/management/jetronic.html , but is doesn't tell which pin is number one, so it is not very helpful at this point.
> Also, According to the Bentley, the O2 system relay, is the one furthest to the right on top. The socket has more than four pins, but the relay is just a tall 4 pin relay, and it does nothing.
> So, Here is what I am looking for. A link to an actual diagram for the wiring. CAn I give this ECU 12v on that green wire? Does this relay just turn the system on with ignition? I need to get this powered up to start troubleshooting, and figure out what I have, as I can't verify what the car has in it. ANY help from anyone here is mucho appreciated, and I thank you all in advance. I want to restore this car, and want to keep it the way it came.


 The power supply (lambda) relay is tied directly to the fuel pump relay. On those early relay panels (I presume your car still has it, or has the newer CE1 panel been swapped in?), the "floating" relays attached to the top of the panel are not in any particular order, so you'll need to find which relay does what via part numbers. The fuel pump relay should have a red fuse mounted on top of it. The power supply relay is (or should be) VW part #171906381. 

The power wire from the lambda relay to the ECU is gray/yellow and enters the ECU at pin 8. Jetronic ECU pin-out list: http://www.cabby-info.com/cis.htm#Pin . Don't have a diagram, yet, of the early relay panel pin-out, but the lambda relay pin-out is: 
Terminal 87 goes to pin 8 on Jetronic ECU via gray/yellow wire. 
Terminal 87b goes to frequency valve via red/yellow wire. 
Terminal 85 goes to ground via brown wire. 
Terminal 86 goes to the relay panel via red/black wire to a harness connector and black/green wire from harness (it is this terminal that connects to the fuel pump relay, internally). 
Terminal 30 goes to pin H on relay panel via red wire. 

So, yes, it's a 5-pin relay, not 4. Make sure a lambda relay is even installed in the car. On the early CIS cars, the lambda relay is also tied into the control pressure regulator, aux air regulator and fuel pump. 

Check that the auxiliary air regulator is working as it should. As for the cold-start valve, make sure its thermo-time switch is functioning properly (and that it's plugged in).


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## rjohns1 (Aug 9, 2006)

Are you sure pin 8 is grey/yellow? I am finding green/yellow.


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