Weber Injection systems

[Haynes David]

Does anyone have any info, or know where I can find it,
on the Weber / Marelli injection system known as
IAW? It is used (apparently) on Lancia Delta twin cams and
Ford Sierra Cosworths as well as some Ferrari
and Maserati models.

I have recently acquired a Lancia Delta  (not turbo) which has
a problem where the engine idle will rise to around
2500rpm. It is probably not directly an idle problem
as the car will not run properly at any other rpms
while under load. It is an intermittent problem which does
not seem to be brought on by any specific circumstance
although it is worse (ie more common) during hot weather.
Has anyone known or heard of similar problems.
Workshop manuals for Deltas are only available from
Lancia at huge cost (unless YOU know different?)

I'm fairly familiar with  Bosch injection / management but
I cant find any info on this system, which measures manifold
pressure and temperature to calculate fuelling. If there is
another vehicle with a similar system that would be useful
as I might be able to get a manual or more info for that.

Sorry if this is the wrong place to post my question as Im
new to this list, but I hope someone has some useful info
for me!

Thanks in anticipation
     Dave H.