quattrofrog

I'm tinkering with converting the AFC back to AAH engine management.

enough of the sensors appear to be the same part numbers.... with exception to the coil and the injectors.

eep

Can you be a bit more specific? The "pure" AFC ECU used in the A4 and later Cabriolets (as opposed to the ECU used in the AAH/AFC engines, which was functionally identical to the AAH ECU) has 32 more pins than the AAH ECU. There's a lot of interaction between the ECU and things like the transmission and climate control that would make a direct swap not work well.

Why do you want to step down to an AAH ECU, anyway? Just wondering.

quattrofrog

92 audi 100 ecu AAH manual FWD ecu

64 pins.

I am playing with the idea of removing the AFC ecu and harness and replacing it with AAH componentry. I have the ecu now and the connectors for it, I was going to modify the harness but I am just going to buy a 100 harness if I go forward with the idea.

Its the Hitachi MMS 201D1 ecu

VAP

By the way your recommendation on the piggy-back system holds promise at least at "first-glance." Tomorrow I'm going to scour all the pin-out diagrams and installation stuff and see if there's a liklihood or even possibility. Thanks for that.

quattrofrog

I'm sad to hear about the results.... but as you said... at least we know now.

BTW if you need anything.... lemme know I work at the stealership now.

quattrofrog

someplace round here I have the diagrams for both 92 100 and 96 A4.

quattrofrog

I know this because it can be used to monitor some data blocks... but the manual trans.... what sort of outputs can it have?

didnt the e-code cars have teh AAH through 1997...

also didnt the A4 HVAC head debut in 1992 on the 100???

scott12v@pghaudi

I'm fairly certain that you are. If this is the case, thank you very much for your efforts in maintaining the site. It is greatly appreciated.

eep

The MMS2xx is missing some really "nice" features such as fully adaptive O2 sensor control - so you'll need the 4-wire MAF sensor, for example, with the CO adjustment screw. I think you can do without most of the other stuff. Compatibilitywise, I think that an MMS3xx ECU (8A0 906 266 E, H, or J) would be easier.

Either way, you'll have to throw away a lot of emissions control equipment, but I'm guessing you aren't too worried about that

Having said that, the basic engine management is basically identical from 1992 to 1997, so with a proper harness you shouldn't have any problems. The fuel injectors and coils operate the same electrically.


Honestly I think it would be possible to make an MMS2xx or MMS3xx ECU drive an AFC engine, but stringing in a new wiring harness, fighting all of the suddenly inoperative vacuum-powered stuff, faking out your climate control system, losing a lot of information on the digital dash (if you have one), etc. aren't worth the potential gains.

Just my $.02 ...

quattrofrog

its a clusterfcuk anyway I flip it...... I know I am going to lose some things... I dont have the driver info display, rather I have the idiot lights... obviously I have a manual trans...

If I need to I'll buy another ecu... hell it was only $60.. not a major investment.

There is much frustration involved in tuning this bastard engine.

this fall/winter I am probably going to buy a 2nd engine and strip it down, then rebuild it to see what I can get out of the 12v. Put all of the lightweight stuff inside, do whatever is necessary to the crankshaft (lightening)... its months and months away but if I dont do that I'll be bored all winter and keep on lusting after stuffing the 3.6 V8 into the A4. If the god damned V6 doesnt want to play nice I'll just have to tear out that silly faux firewall and buy another radiator carrier to chop up so the bay can accept the V8.

meantime I'm putting this in and buying the 272 cams later this week.

<img src="http://pictureposter.audiworld.com/44061/p1010019.jpg">

Time as alays will tell