Date: Wed, 30 Jun 2004 04:59:34 -0400
Reply-To: Sam Payne <bungeegull@HOTMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Sam Payne <bungeegull@HOTMAIL.COM>
Subject: audi 3A Swap -- Jetronic LH 2.4 question
I'm in the delirious beginnings of putting an audi 80 2.0 engine in my
86 vanagon and running it off of a Bosch Jetronic LH 2.4 FI--a result of
poaching Frank Grunthaner's painstaking research in his pursuit of the
Turbo Audiagon.
I got the Saab Bentley and Probst's excellent book 'Bosch Fuel
injection & Engine Management' and read for awhile. Turns out the post '86
non-turbo Saabs use a non-advancing distributor just like the audi 80, so
I'll be spared Frank' distributor mods. I decided to try for an '88 Saab
donor because it ran LH 2.4 (which is a bit more refined than 2.2 in that
it has does away with the throttle dashpot and has adaptive idle and
mixture control and on-board diagnostics) and because it had the hall
sensor in the distributor. The Saab '89 and '90 models mount the sensor
beneath the crank pulley. The Audi 80 has the hall sensor in the
distributor.
Armed with this knowledge I set forth into the wilderness of 5 local
Pick 'n Pull yards and a couple of independant ones--sheer undiluted
pleasure--and found several strange phenomena. First, every year but the
one you want is there. Second, there are a bunch of guys who go from car
to car stripping only the relays out. There was at least one in every yard
I visited, they got to every Saab I saw first. (What do they do with all
those relays?) Third, most of the air-mass meters were gone, especially
the plastic-bodied post '87 ones, which aren't interchangeable with the
earlier ones. This last I expected.
So in the heat of the mid-day California sun I broke down and stripped
the only complete (minus relays) contender I could find: an '89. The
wiring diagrams in Bentley show three wires coming from the Hall sensor in
both the distributor-mounted version and the crank pulley mounted version.
They attach to the same terminals in the ignition control unit, BUT the
crank pulley mounted version uses thicker wires: .75 instead of .5. I
guess that the point of the crank-pulley mounting is to improve sensor
accuracy, so (now that I'm out of the sun) it seems likely that the Bosch
engineers also reprogrammed the Ignition Control unit and the FI control
unit to take advantage of that. If they did, will it work well with my
audi 3A's distributor-mounted hall sensor????? I looked into pulling the
pulley mounted sensor out of the '89 Saab, but the crank pulley is right
up against the firewall (backwards-mounted engine!) and I think I'd have
to pull the engine first.
Advice? Absinthe?
Congratulations to Alastair, thanks to Frank for an interesting project.
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