ecu interchange?

under the radar · Post by **under the radar** » Tue Jun 09, 2009 7:34 pm

my '79 e12 came with a ecu # 0 280 001 118, i think its the original, but have no way of knowing for sure. can i use a ecu with the # 0 280 001 122?

Post by **John in Simi Valley** » Tue Jun 09, 2009 7:39 pm

Yes, the -122 will work in place of the -118.
I've switched them as an experiment on past cars, either seems to work fine.

If you need a '118, email me off line.
I think I have an extra, just pay shipping.

under the radar · Post by **under the radar** » Tue Jun 09, 2009 7:56 pm

thanks john, i sure do appreciate it. i'll send you a email for sure.

under the radar · Post by **under the radar** » Tue Jun 09, 2009 8:06 pm

e-mail sent

alotawatts · Post by **alotawatts** » Tue Jun 09, 2009 11:59 pm

John in Simi Valley wrote:Yes, the -122 will work in place of the -118.

These numbers must correspond to build years correct ? If so which number is which year ..or vise versa... ?
Ive been wondering if my 79 will work in my 81's !
And OT but I'm wondering about the distributors also...different numbers for 79 - 80/81

Mike W. · Post by **Mike W.** » Wed Jun 10, 2009 12:44 pm

The 118 ECU was 79 only, then they went to the later one. IIRC the main difference is one, I think the early one, goes to closed loop based on temp and the later one does it by O2 output.

Distributors may be dual diaphram or single, but I'm not sure on that one.

T.Hanson · Post by **T.Hanson** » Wed Jun 10, 2009 10:19 pm

I understand to pay attention to serial numbers. If I cleaned up a parts car distributor or other component, don't just switch the cruddy one from the '81 being rebuilt, to a clean one that looks the same, as it may not be.

Distributor now, as I was informed all that came off was a running group and changing things wholesale invited a calamity of variables if the new group didn't run.

douginky · Post by **douginky** » Thu Jun 11, 2009 8:04 am

FYI, the 79 harnesss probably won't have the pin for the o2 sensor. You can unplug the harness, solder a small wire to the pin on the ecu and run it thru the hole in the plug to connect to an O2. Gently guide the wire thru the plug while plugging back up to the ecu. Don't remember the pin #, but it's on the pin out in faq section.

Mike W. · Post by **Mike W.** » Thu Jun 11, 2009 1:02 pm

douginky wrote:FYI, the 79 harnesss probably won't have the pin for the o2 sensor. You can unplug the harness, solder a small wire to the pin on the ecu and run it thru the hole in the plug to connect to an O2. Gently guide the wire thru the plug while plugging back up to the ecu. Don't remember the pin #, but it's on the pin out in faq section.

Uh, no, on US spec cars it will. 79 was the first year BMW went to O2 sensor and 3 way cat on a car, it was 528i specific and the rest of the line kept the evil thermo reactors. Unless it's been hacked, and badly, a 79 is definitely set up for an O2 sensor.

under the radar · Post by **under the radar** » Thu Jun 11, 2009 7:09 pm

my car, the car in question here, has an o2 sensor and a cat. but has a 118 ECU.