Differences in ECU between the years?

russwiththebus

My situation is that I have a 1978 Westy with a transplanted engine. The block came from an air-cooled Vanagon but the heads are correct for the year model. Previous owner installed a center-mounted Weber carb, and I am in the planning stages of making it fuel injected again.

I've amassed a bunch of new and used parts to use, and I almost have everything I need. My question is, I have two ECUs here that have different part numbers and I want to know what the difference is, and/or if it matters which one I use.

Here's the first ECU I have, it's the original from the 1978 bus. VW part # 022 906 021 AG (Bosch part # 0 280 000 166) with a purple sticker.

Image may have been reduced in size. Click image to view fullscreen.

The thing is that it rattled when I pulled it out, so I opened it up to discover why. It looks like one of the little black star-shaped heat sinks (at least I think they're heat sinks) is unglued on the far left. Here's a close-up of the piece.

Is it a problem to leave it off, or can it be re-glued perhaps?

Now on to my second ECU. This one came out of a box of parts I bought from someone. I think his bus is a '76 and that's what the majority of these parts came off of. His ECU has a different part number, 0 399 060 21B (Bosch part # 0 280 000 178) and has a black label. When I opened it up, I was surprised to find a second PCB inside, screwed down.

It connects to the other PCB via a few wires on the side.

So what's the deal? Are they functionally the same, despite their differences? Can I use either one on my bus, or does it have to be matched to a certain part, like the AFM or something?

Thanks.

MadMax78 · Posted: Tue Jun 10, 2008 5:12 pm Post subject:

ECU, CU 102 X - 039 906 021 B
Volkswagen
1979 Type 2 1970cc (CJ,GE) Except California Manual Transmission
1983-80 Vanagon 1970cc (CV) Except California Manual Transmission

ECU, CU 99 X - 022 906 021 AG
Volkswagen
1978 Type 2 1970cc (CJ,GE) Manual Transmission

Strange, at first I thought it may have had to do with the lambda system on Cali systems, but the ecu part numbers prove they are both fedederal manual transmission ecu's. Maybe it's for the altitude correction switch...? Or do all vanagons have the lambda sensor? Then that board would control the mixture...

Cool pics btw, always wondered how it would look on the inside!
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Wildthings · Samba Member Joined: March 13, 2005 Posts: 51776

Early 76 units did not use the throttle position switches, which many might view as a plus. There are also 6 plug and 7 plug AFM IIRC, and I suspect there were other changes over the years as well. To eliminate problems I would suggest you find a matching set of harness, ECU, and peripherals. Then again I really don't know much about this area and could be all wet.

Randy in Maine · Posted: Tue Jun 10, 2008 6:01 pm Post subject:

Possibly the ECU internal "series resister" since a CA bus doesn't use the one on the firewall?

vw76westy · Posted: Tue Jun 10, 2008 6:47 pm Post subject:

im no expert but the ecu, the air flow meter ,harness & injecters
have to all come from the same year in order work right
i have also read that the engine year should also match in order to avoid
problems later
regardless of what year system you choose

russwiththebus · Posted: Tue Jun 10, 2008 8:19 pm Post subject:

All interesting ideas, thanks! As far as I know, none of these parts came from California buses, so I don't know it's lambada. Also the wiring harness I got came with series resistors, so I don't know if that's it either. I do plan on trying to keep everything intact as possible though, so I'll probably go with the '76 ECU first. And luckily they're easy enough to trade out, so that won't be a problem either.

Also I don't believe the L-Jetronic system changed much between '75 and '79, at least for non-California emissions so swapping parts should work. I meant it works off air flow so it's not like it cares how big the engine is or anything.

Either way it should be an interesting experiment getting it working.

Karl · Posted: Tue Jun 10, 2008 8:50 pm Post subject: ECU Karl

Only 79 Calif had the O2 sensor and no resistor pack.

I have a box full of ECU's. I used to grab them many years ago.... before I found out how bullet proof they are. Most 'mechanics' do not have a clue that they need to test first. 99% of them are 'parts replacers' and do repairs using the Mossberg Repair Procedure. Shotgun a sh!tload of parts at it til it runs.....

I would test each ECU on my 77 bus to see if it worked. Everyone did. Each year has 4 ECU's..... why? No friggin clue. My bus ran the same with each one!

California Models:

022-906-021K 1974 Automatic

022-906-021L 1975 Manual Trans

022-906-021M 1975 Automatic

022-906-021Q 1976 Manual Trans

022-906-021R 1976 Automatic

022-906-021AA 1977 Manual Trans

022-906-021AB 1977 Automatic

022-906-021AE 1978 Manual Trans

022-906-021AF 1978 Automatic

039-906-021D 1979 Manual Trans

039-906-021E 1979 Automatic

Federal Models:

022-906-021H 1975 Manual Trans

022-906-021J 1975 Automatic

022-906-021N 1976 Manual Trans

022-906-021P 1976 Automatic

022-906-021S 1977 Manual Trans

022-906-021T 1977 Automatic

022-906-021AG 1978 Manual Trans

022-906-021AH 1978 Automatic

039-906-021B 1979 Manual Trans

039-906-021C 1979 Automatic

Vanagon:

California Models:
071-906-021B All Transmissions 1980-1983 (071 plain and 071 E subbed to the 071B!)

Federal Models:
039-906-021E Manual Trans 1980-1983

039-906-021C Automatic 1980-1983

russwiththebus · Posted: Wed Jun 11, 2008 6:31 am Post subject:

Thanks Karl, that's interesting!

WhirledTraveller · Posted: Mon Dec 22, 2008 2:19 pm Post subject:

Resurrecting this thread,

I have acquired a bunch of F.I. parts for spares from a 78 Federal Manual Transmission. I have a 77 Federal Automatic.

The AFM has a slightly different part number, as does the ECU.

Does anybody know with certainty weather these parts truly interchange or don't? Anybody know, for example, what the difference is between an automatic and a manual transmission ECU?

Basically just want to know whether these are useful spares worth keeping.
_________________
1977 Westy, Automatic. Big Valve heads, CS Cam.

Karl · Posted: Mon Dec 22, 2008 2:26 pm Post subject:

WhirledTraveller · Posted: Mon Dec 22, 2008 2:28 pm Post subject:

Thanks Karl. You are correct on the part numbers. Good to know.
_________________
1977 Westy, Automatic. Big Valve heads, CS Cam.

asbug · Posted: Tue Dec 23, 2008 6:53 am Post subject:

So if I understand correctly,
The AFM doesn't matter if it came from an Automatic or a manual as long as it's a 7 or 6 pin respectively?
Thanks,
My early 76 Westy Automatic Delux has a 1.8L and a worn AFM plate, I have moved over the plate and it runs great now (after alot of work....) and am going to be looking for a better AFM for the thing...
Thanks,
KC Very Happy

kevin77westy · Posted: Tue Dec 23, 2008 8:54 am Post subject:

Karl · Posted: Tue Dec 23, 2008 10:22 am Post subject:

Vamstad · Posted: Mon Jan 12, 2009 5:53 pm Post subject:

Damn Karl, that is good information for me!! Cool

I have a new, rebuilt AFM from a buddy that has the 018 part# that he was unable to return due to an open package (for his 77 FI bus).

Thinking that I had an AFM issue on my 79 FI Federal bus, I installed it (took out the stock 020)...did an idle speed adjustment (dwell and timing fine) and my bus ran like a champ! We are talking a real "smooth operator".

When I paid closer attention to the part numbers on the box (from fuel injection corp) I was surprized to find the part number difference. I was really, really close to purchasing a different AFM to match my bus exactly....until I read your post.

Just to confirm, you mentioned that a 020 would work in the place of a 018. How about the reverse of this (018 rebuild in place of the stock 020) like my setup?

Thanks again!
_________________
Fear is the mind killer.
1979 Federal Westfalia
2.0 FI

vw76westy · Posted: Mon Jan 12, 2009 6:42 pm Post subject:

i also want to know if the 018 is usable in a 77-79 bus

1977_L63H_P27 · Posted: Mon Jan 12, 2009 8:05 pm Post subject:

asbug · Posted: Tue Jan 13, 2009 9:33 am Post subject:

dweomer21 · Posted: Tue Jan 20, 2009 1:10 pm Post subject:

Karl, are you getting your info from any place in particular, or just from general past experience? I ask because I'd like to know if this AFM on ebay (ref. Carter part# 349-028) would be compatible with my '82 Fed. M/T Camper (my current damaged AFM # is 280 200 028 / 071 906 301A).
I don't mind doing the research myself, if I knew where I could cross-reference part #'s and such. Also, I don't want to fork this thread too much, or get off topic; if I crossed the line there, my apologies Wink

davis911s · Posted: Tue Jan 20, 2009 10:29 pm Post subject:

So what about for a 75 AUTOMATIC? Are these interchangable or a one year only?

Shawn
_________________
"I choose to use CAA on old cars with character...instead of car payments on a new car Smile

"

1973 Westfalia, Camper Special with 75 FI. Automatic 003 . Non-pop top
1977 Porsche 911S Targa, 2.7 L with 5spd
1992 Passat G60 Syncro Wagon (SOLD)
1975 Westfalia (SOLD)
1979 Westfalia (SOLD)


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