re. '86 5kt. MAC 11B or MAC 11C ECU? which one?

Ben Swann benswann at
Fri Jan 13 07:26:37 EST 2006

I stand corrected, slightly.  It was the MAC-10 that is functionally 
equivalent to the 11-B and C, and changes involve some circuitry and code 
(what I'd term bug fixes or patches) even though the MAC-10 works just fine 
as a substitute.  the MAC-11B and C are nearly identical with only slight 
changes in the code.

I have seen the MAC-11C in '86's including the automatics, however concur, 
it is more likely to find the MAC-11B in the earlier models especially the 
automatics.  I don't know why there is the mix and match, as it would make 
sense that there would be a unit more suitable for auto. and one more 
suitable for manual.  but there is no logic to which units you will find in 
which vehicle.  The MAC-11 becomes the preominant unit that is found in the 
later '87 and '88 vehicles.



[Date: Thu, 12 Jan 2006 20:39:47 -0800
From: "urq" <urq at>
Subject: Re: re. '86 5kt.   MAC 11B or MAC 11C ECU?    which one?
To: <quattro at>
Message-ID: <002801c617fb$62bf6b60$6400a8c0 at fasthp>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";

... I'd expect an '86 to have a MAC-11B ... ISTR seeing the MAC-11C in '87.
I've got the binaries for both somewhere ... my recollection is that the
MAC-11B code runs the engine a little less lean.  I don't think there's any
"bug fixes" ...

As noted, they are interchangeable ...

> I've Seen both - Mac-11C is more or less a bug fix for the 11-B.  Both are 
> interchangeable.
> > which ECU does the '86 5000 Turbo Automatic use?  MAC 11B  or MAC 11C?] 

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