Difference between 1980 CIS & 1981 CIS
 

Anyone know the difference between 1980 and 1981 CIS ? I have a 1981 CIS and want to put it on my 1980sc.

I thing I think is the 1981 had steel injector lines, which probably makes no difference.

There may be some Lambda controller wiring differences. I don't have access to my schematics until tonight. But if you have factory manuals they show the wiring.

No difference.

CIS unit.......
 

If you are putting the complete '81 CIS unit, then it is just an installation process. There are some differences between '80 and '81-'83 CIS components like WUR, FD, ECU, and fuel lines. You could mixed match the components and still have a good running CIS if you know what you are doing. Also be aware of the differences between USA and RoW models. They are similar until the introduction of the lambda system in '80. Why are you replacing the '80 CIS? Are you having some sort of problem? What happens after installing the '81 CIS and you still have problem/s? Keep us posted.


Tony

As Tony said, many components are different. Look here to see which ones.

911 CIS Primer - Cross Reference

I bought the car with motor and tranny out and th PO said there was problems with the 1980 CIS. It came with another CIS from 1981 which he never installed, it's in better shape so I figured I would use it.

I see the 81 has an additional temp,throttle and enrichment switch compared to the 1980 CIS.

The control unit is different. Do you have the 81 unit ?

The CIS primer says plastic fuel lines where used up through 79. Supposedly the CIS that came with the car is a 1980 but it has plastic lines? The 81 has metal lines and several differences including the control box. I think I might be ready for carbs!

80 has plastic lines.

Tony's the expert in these systems. What's wrong with your current setup ?

Ok thanks

I don't have a set up right now CIS was off motor when I purchased the car po said it had problems and no one could fix it so car was parked. Motor is out getting rebuilt soon and just trying to sort out my options for fuel delivery.

From what I have read I guess I will have to stick with the 1980's one and try to sort things out and use the 81 for its parts.

Hold on there for a little second. Just chew on it for a while.

There are a handful of additional controls the 81 box has that the 80 does not. Most importantly, a WOT switch that you should be able to take advantage of.

Listen to pmax and consider Tony (and timmy2) as your new best friend.

Alternatively, go to carbs, get a few more ponies and drop you mileage 10mpg. Don't mind the myriad carb hassles and their cost.

You can install the 81, using the lambda harness on the engine from the 80 so you match at the connector and the lambda system. The 80 has a 6 pin connector coming off the engine to match the chassis harness. The 81to 83 has a 12 pin connector off the engine.
Bruce

Now I'm a little confused according to the CIS primer the CIS shown in my pic is a 1981 due to the 2nd throttle switch however it has a 6 pin connector as shown. Bare with me guys I'm new to CIS.http://forums.pelicanparts.com/uploa...1444174984.jpg

Here's a few more pics maybe I'm wrong but it appears to be a 1981 CIS.http://forums.pelicanparts.com/uploa...1444175356.jpg
http://forums.pelicanparts.com/uploa...1444175394.jpg

My mistake I guess I must have transferred the wiring off the 80 over to the 81 last year.

Pictures in posts #17 and #18.........
 

DP,

Are those pictures of your spare CIS unit or the one installed in your motor? The engine wire harness in the picture is from an '80 CIS with 6-pin. Could you post a picture of the chain housing cover for cylinders 4-5-6 of your motor? Other identifying features would be (for your motor):
a). What is the Bosch ID numbers on the ECU?
b). What is the Bosch ID numbers on the WUR?
c). What is the serial number on your engine block?

If you could provide these information, we might be able to decipher the true identity of your motor unless PO installed assorted CIS components in your engine. So let's take it one step at a time.

Tony

I want to know if I can use a 1981 CIS in place of the 1980 CIS. Car is stock 1980sc with original motor,ecu et. The reason the 81 CIS in the photo above had the 6 plug was because I put it on there last year and forgot I did it.All I want to know is if I can use the 12 pin 81 CIS in MY 80 6 pin car without too much trouble.

The two systems have enough differences that you need to swap all of the different components. Mixing and matching is never a good idea. The first step in that direction is to understand what the differences were, so I'd suggest getting copies of the technical training documents for both years, a copy of PET, and do a few nights of studying.

You can also consider keeping what you have and fixing it. Just because the previous owner said the system was bad doesn't mean **** to me. He could have been an idiot, at the very least probably didn't fully understand CIS anyway, and there's nothing in a CIS system that can't be fixed. The problem is most people short-cut the diagnosis, trying to find the one bad part before understanding how everything is working. If the symptom is this, the cause must be....

The other side of the coin is that you have no idea what condition the 1981 components are in; there could be as many problems there as what you have.

JR

Steel injector lines.
Cold start fuel mixture distributor in plenum.
Shear-off screw plugging the mixture control hole.
Acceleration enrichment via O2 sensor, which requires:
Additional throttle microswitch
Temp switch in crankcase vent cover
Extra control unit for enrichment function
Different control unit with connections for above
Wiring to accommodate the above
Different WUR

In addition, there was a different fuel pump, fuel filter, fuel accumulator and a new cat.

No difference.... :rolleyes: why give this advice?

JR

Thank You