ECU's

[Inline_6]

I need a little information, if possible, on differences between ECU units for my car. The original was a 0.261.200.000 I think. I replaced it with a 027 that was suppose to be a upgrade however, since I've installed another 000 unit, the car runs a lot better. Maybe the reman 027 was a bad one who knows. When starting the engine, cold or hot, day or night, the engine revved high. It's not doing this now so I have to assume the reman had a problem. It wasn't the DAC motor or it's computer doing this revving.

I just purchaced a Jim Conforti chip. Opened the old 000 ECU and found it doesn't have a removable EPROM socket. Now I'm wondering if the aftermarket chips are a fix for the upgraded (027) ECU's. I understand the rev limit is higher, although I've never felt the rev limiter and I've had the needle to five without a cutout.

There are several computers for my car it looks like. All these are for 10/83 to 4/94...000, 027, 024, 154. Before I start thinking I need to find a certain number computer to put this chip in, what am I looking for? What were the upgrades on the 027? was it fuel economy, emisions? Anyone??????

 

[rjp325i]

Go to the Bonneville Motor Werks web site. It lists the Digital Motronics Application guide. Is your engine an "e" or an "i". From what I understand the ECUs are not interchangeable. There is Motronic 1.0, 1.1, and 1.3. They were all used from 1984-1991. For the "e" the 0-261-200-027 with basic 1.0 was used from 1984-1987. In 1988, "the super eta" engine used 0-261-200-154 with Motronic 1.1. The "i" used 0-161-200-153 w/Motronic 1.1, 173 (my 1989), 351, 380, 382, 524, 525, and 526 all with Motronic 1.3. There is no listing for a "000". The Bentley manual is incomplete in this area so I went to the Bonnevile site (Conforti). The M3s used different ECUs also. The "Check Engine" light is only on the Motronic 1.1 and higher.

 

[jrt67ss350]

So only cars that have Motronic 1.1 or higher have a check engine light? I have a 1987 325e that has a Check Engine light with a bulb in it in the dash cluster, but it never lights up when you start the car as a bulb check. I know the bulb is good. The fact that it never lights up would make sense if my car's computer doesn't use the check engine light. So why would they have put the bulb and wiring for the bulb in the harness? How are you supposed to know when something goes wrong with a sensor?

 

[rjp325i]

According to the Bentley manual and Conforti site you have a 1.0 Motronic system (see page 36 of Fuel system). Only the "super eta" engine of 1988 had the later system. The dashboard light might just be because the same dash is used in the 325i as well and that used a 1.1 system. I don't know. However so many things with BMW depends on the date of manufacture who knows. I'm reading what the various manuals are saying is in the cars. Do you have a Bentley manual? While it is not 100% in all areas, it is the best available. I also have a Haynes, that is OK for routine work, but far less detailed. I have both in case 1 has info the other might not. The listing of the ECUs I gave you is from the Conforti site (www.Bonnevillemotorwerks.com). Turner Motorsport, a distributor of the Conforti chips should be able to give you more detail. Have the ECU number and the date of mfg handy if you call. If you would like me to give you more detail on the differences between 1.0 and 1.1 I can. It's just that the Bentley does not get into 1.3 which you do not have anyway. If you are a BMW CCA member you can call one of several professional tech advisors (free) for more detailed info.