Someone set me straight on what ECU need to find!

arminyack

Member
Joined
Jan 11, 2021
Location
Claremont, Ca
TDI
1973 VW Bus ALH
Greetings!

So I have acquired an ALH engine pulled from a 1999 Beetle. I am in the opening stages of swapping this into my '73 VW Bus. What I am looking for right now, is the right ECU. Is it an 80 pin ECU, or a 121 pin? How can I find what engine I have? From what I've gathered so far, 1999.5 there was a change over? Is this correct?
 

compu_85

Gadget Guy
Joined
Sep 29, 2003
Location
Springfield VA
TDI
... None :S
2000 was the change over year - 98 and 99s have the simpler ECU.

That said, if you don't have the harness, you can use the later computer and harness with your engine. The only real change was thes shape of some of the connectors for 2003.

-J
 

arminyack

Member
Joined
Jan 11, 2021
Location
Claremont, Ca
TDI
1973 VW Bus ALH
I do not have the harness...I plan on using Fast Forward to build me a harness. That being said...would I be better off with the later ECU? I know I would have to have the immobilizer deleted, which is added expense, bit might be better when it comes to modifying at a later date?
 

compu_85

Gadget Guy
Joined
Sep 29, 2003
Location
Springfield VA
TDI
... None :S
The later ECUs can give smoother running in some circumstances.
If you use a 98/99 ECU you'll want a tune anyway to fix the hot start map (which VW forgot to load in)
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis (where it's safe)
TDI
There are just too many to list....
You'll want the later ECU, given the choice. Since you'll be changing software regardless. If you already had the early ECU/harness, you could certainly use that. But if you don't, then may as well source the later one. The engine itself won't matter, aside from having to change a couple sensors. The cooling fans and A/C system is a little different, too, but that will likely not be a concern on a swap like yours.
 

arminyack

Member
Joined
Jan 11, 2021
Location
Claremont, Ca
TDI
1973 VW Bus ALH
So then I'm thinking the ECU I want is a 038 906 012 XX, where XX stand for the car & manual or automatic transmission? Also, can someone point to the right direction of the benefits of deleting the EGR and such?
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis (where it's safe)
TDI
There are just too many to list....
Manual or automatic is done via soft coding of the ECU. The ECU itself is the same, so that makes no difference.

The EGR is there for NOx control. Back before we had ULSD, the EGR system allowed a lot of carbon build up in the intake manifold, especially if the engine was driven too easy too much of the time. With ULSD, this issue is greatly (but not entirely) reduced. I'd go so far as to say it is mostly a non-issue anymore, but if you are going to be doing software mods anyway chances are that'll get changed too. With no EGR, depending on the power output level, you'll also greatly reduce the soot load on the oil. I have two ALHs (in their original habitat, a Golf), one with and one without. The one without goes 20k miles on its oil, and it takes 5k miles just to turn black. However, it also takes longer in cold weather to warm up, and cabin heat takes longer, as there is no heat exchange because there is no EGR cooler.

I do not know what rules the People's Republic of California has regarding an ALH swap into something from 1973, you may want to investigate that.
 

arminyack

Member
Joined
Jan 11, 2021
Location
Claremont, Ca
TDI
1973 VW Bus ALH
Thanks for the responses. I'll probably delete it. I have much clean up work, and familiarization on the ALH engine, to do. I normal live in a automotive world of vintage Alfa Romeo's and BMW's, so this whole business of ECU's, smog control systems is foggy territory for me.

As far as Kalifornia smog rules, anything MY 1975 and earlier is exempt.
 
Top