ABY VS AAN engine harness

[LukasR]

hi there. My name is Lukas and Iam new Here
I am in the process of collecting parts at the moment to do swap 3b or aby into coupe quattro 20v 1991.
what are the major differences in engine harness aby and aan,and wich one is easier to fit.
I have choice to choose from:
aan-s4 c4
aby s2 avant
i want to run standard k24 7000 at the moment on the 3b block and head as i currently have those sitting in my garrage. Only distributor is missing.
Any advice is welcome.

[Greg_S]

Welcome onto the site. I don't have first hand experience, I expect the aan would be easier as there is a lot of electrical knowledge on its setup and it is a slightly more modern setup. Be good to see your project so far

[Error404]

Both are technically plug n play but AAN won't fit without modification, due to different chassis and engine component locations. AAN uses some different connectors at the fuse board end too. Personally I'd probably use the 3B harness and do the pin swap / add coils to run an ABY / AAN ECU and COPs

[quattrostyle]

He says he can choose between S2 avant = ABY and AAN, surely ABY is the best option then.

[LukasR]

I was considering 3b loom as it is the cheapest option on the market at the moment,(Ebay.de)
I belive that someone could provide me with details or schematics or just post the link.

[UrS4boy]

i want to run standard k24 7000 at the moment on the 3b block and head as i currently have those sitting in my garrage. Only distributor is missing.
Any advice is welcome.

If you want to start with the 3B and use an ABY or AAN ecu, you will need the 3B distributor to run the hall sender (G40) signal to the ABY (or AAN) ECU.

The pin swap info is available here:

http://www.s2-audi.co.uk/tech_articles/motronic/ecu.htm

Paul Nugent at S2Central.net also has the two pin-swap documents attached below:



Good luck.

[LukasR]

thanks for the info.
I'll go 3b way, just seen on another post that Error404 can supply some coil pack conversion loom, wich iam going to be interested.
best regards lukas

[Error404]

Yes just let me know if you need help with the harness

[LukasR]

As soon as i receive the engine harness i'll get in touch with you(Error404)
Any recomendation as what ecu?
any particular model year or part number?
regards Lukas

[UrS4boy]

3B to AAN/ABY ECU suggestions

As soon as i receive the engine harness i'll get in touch with you(Error404) Any recomendation as what ecu? any particular model year or part number?
regards Lukas

Prj (our resident Motronic guru (when he shows up)) says:

Both (AAN and ABY ECUs) handle MFTS signal exactly the same.
They are interchangeable. On AAN the MFTS signal simply isn't wired into the ECU plug.
Put it there, and it will behave just like ABY.

I (UrS4boy) would say that you would probably want to avoid the ECUs with immobilizers.

More info in these links:

AAN ECU: http://www.s2forum.com/forum/showthr...ht=ECU+pin-out

ABY ECU: http://www.s2forum.com/forum/showthr...ht=ECU+pin-out

551AA is the AAN non-immo ECU:



551A is the ABY non-immo ECU:

[LukasR]

thanks for the info,
I have found one 4a0907551c for around £280 comes from s6 c4, the owner advertise it as it has:
changed "map sensor" to 300kPa? and it can reach 300ps on standard injectors and turbo?
any coments, advice, welcome

[UrS4boy]

I have found one 4a0907551c for around £280 comes from s6 c4, the owner advertise it as it has:changed "map sensor" to 300kPa? and it can reach 300ps on standard injectors and turbo? any coments, advice, welcome

Prj (our resident Motronic guru (when he shows up)) says:

I (UrS4boy) would say that you would probably want to avoid the ECUs with immobilizers.

More info in these links:

AAN ECU: http://www.s2forum.com/forum/showthr...ht=ECU+pin-out

ABY ECU: http://www.s2forum.com/forum/showthr...ht=ECU+pin-out

551AA is the AAN non-immo ECU:



551A is the ABY non-immo ECU:

From that AAN info link that I provided:

"AAN Motronic ECU Part Numbers:
551A early UrS4 with pseudo dizzy and 8k boost chip
551AA UrS4 non-immo, Europe and America
551B UrS4 same as 551AA, but auto
551C UrS6 incorporates all software updates from RS2, different codebase, more diagnostics
551D UrS6 same as 551C but auto (see photos at the end of this post)
551E UrS6 has a small tweak to fuel on cold start
551F UrS6 same as 551E but auto.

At 551C, when the immo got incorporated, the RS2 codebase was merged as well. Yes, all are still 230hp DIN, 227 hp SAE), but many routines are rewritten. For example the rev limiter routine is different, the software code area in the boost/knock control unit is 200 bytes longer and so on."

So the 551C that you are considering is the immobilizer ECU that I was trying to steer you away from. Unless you can figure a way around the immobilizer (part of the key function and an attached black box), then you will have problems (In my opinion).

The 300 kPA MAP sensor and "300 PS" indicates that the ECU has been "chipped" with somebody's Stage 1+ chip set (2 chips). "300 PS" is a bit of the merde de monsieur vache but it certainly is common to use with the stock K24-7000 turbo and injectors.

Some reading for you:

Click on the G71 live label on the upper middle left of this live Engine Bay Device Map:

http://members.shaw.ca/ajmills/UrS%20Engine%20Bay%20Device%20Map.html

[LukasR]

hi Urs4boy,
i did post the questions without reading yours attachments,
Now I see all is there
Germans are selling those non immo ones but they pricey a bit...
Thanks again

[LukasR]

Could Any One Point Out Any Differences On Audi 200 20v 3b Vs Audi S2 3b Engine Loom?

[afterthought]

Lukas if you need one I have a 3B harness and I am just across the border from you.