ECU Lamda control unit

[911carl]

Hello,
I have a 911 sc '83 (USA version) and I want to be sure that I have the correct control unit for the lambda system. The original ID tags on my control unit are not readable anymore but on the box is written by hand Porsche number 931 617 101 01. This seems to correspond to Bosch number 0 280 800 037 which should be for a '81 model, while I should have a Bosch number 0280 800 055, correct?
Is there a way to be sure that the number written on the box is the correct one? The original tag was a yellow sticker. When I Google both Bosch numbers it looks like
0 280 800 037 used a blue ID tag. This might indicate that the number written by hand is not the correct one... Don't know if the inside tells more?
Thanks for your help!

[911carl]

Pictures from the inside

[tirwin]

According to Jim William's page, '83 had the -055 ECU and the 101 00 Porsche part number corresponds to an '80. I did not see 101 01 listed on his page, but I'm on my phone so maybe I missed it.

911 CIS Primer - Cross Reference

I also have it in my head that there were minor ECU differences between '81-'83 but I don't see that reflected in different part numbers so I'm not sure how you would know exactly which year model an ECU was actually from unless there is some other identifying information on it.

[Flat6pac]

The 80 only used a 6 pin on the front of the motor, all the rest used a 12 pin connector

[tirwin]

If I remember correctly, only 6 of the 12 pins are used on the 12-pin connector.

[911carl]

Apparently 911 617 103 00 and 911 617 101 01 are interchangeable. Question is then how one can see the difference between an '81 and '83 version?

[Bob Kontak]

Below is a post from javadog. See this quote in post #37 of the link. The diagrams and tables he posted are terrific hip pocket info.

Not sure if it's 2.5 or 25 seconds but does not seem to be a deal breaker for using either box - assumption only. I think I understand it now. 83 enrichment was extended from 2.5 to 25 seconds post O2 warm-up.

Originally Posted by javadog

This is from 1981, when Porsche introduced the O2 sensor control unit. I don't think they made any changes to it until 1983 when a new unit was introduced. The main difference in 1983 was that the enrichment was kept in place until 25 seconds after the O2 sensor was warm. The enrichment was for 2.5 seconds, which may be a little longer than the enrichment in 1981.

Low power in low RPMs after reconnecting O2 sensor

[911carl]

Thanks Bob, good to know that the box will work anyway before spending money on the refurbishment.

[SCadaddle]

From the one in my 82SC, very early USA production model built in June of 1981.

[SCadaddle]

Rotated similar to your photo.

[boyt911sc]

1980 SC.............006 (Black label).

1981 SC.............037 (Blue label).

1982 SC.............055 ( Yellow label).

1983 SC.............055 ( Yellow label) and 062 (Red label).

Except for '80 SC ECU (006), the 037, 055, and 062 are interchangeable with minor differences to consider.

Tony

[911carl]

Thanks for the update Tony! I've send my ECU back home to Germany today at the Bosch Classic center. Hope they can fix it over there...