I recently bought a 93 Golf. The IP on the spare engine that came with it has some parts I don't recognize.

My numbers are a bit off. So:
What is #2? It's on both of my AAZ IPs but not on the 1.6
What is under the cover #3 and the adjoining hose #1? These are on none of my other pumps. This IP came (supposedly) from a 94 Golf.
One other thing. The Bentley states in the General Information section that the 1.9 is an ECOdiesel engine. Is this right?
johann
#2 is a hydraulic timing advance solenoid... the tiny pipe steals a bit of diesel fuel under pressure to hydraulically drive an advance mechanism when power is applied to the white connector at the end of the solenoid. Power is generally applied to the solenoid except under deacceleration where retarding the timing reduces emissions and (very slightly) improves fuel economy.
The "hot-rod trick" is to wire this to power permanently... for example, the start solenoid line. This leaves the timing on full advance at all times.
#3 hides a micro switch that senses throttle position and is used to control things like #3. I'm thinking #1 is the wiring from this switch rather than a hose... at least it is on my AAZ.
The "hot-rod" trick is to delete the cover and microswitch... insulating the existing wires so that they can't complete the circuit. Without a timing advance solenoid the microswitch is pretty much useless.
I vaguely remember one other thing the microswitch controls but I can't recall... someone else may chime in.
In my mind an EcoDiesel is a diesel with a turbo but no fuel enrichment on the pump... also usually has a catalytic converter.
Your engine appears to have fuel enrichment so in my mind it's a full fledged turbo diesel with 75 potential horses raring to go !!! My guess is that the "Eco" moniker on this particular setup refers to the using the microswitch and solenoid to eek out a bit more fuel economy.
I
Vince
The micro switch partially controls the wastegate on cars fitted with the ko3 turbo and controls the egr on passats.
The advance solinoid is controled by engine RPM I believe it recives 12v at 2800 or 3000 rpm! It may get the signal from the cluster???
Thanks for the replies. I don't know much about this engine although it seems almost identical to the 1.6. Did all the AAZs have the microswitch? My 93 doesn't. Was it not added until 94 or has it more likely been hot-rodded?
Johann
Here's a thread on hopping up the AAZ... the first couple of steps talk about the functions of the parts you're referencing:
http://vwdiesel.net/phpBB/viewtopic.php?t=579It looks like the microswitch actually controls turbo activity with the solenoid being operated by rpm via the cluster... again someone else may step in here.
I have an 94 AAZ and it has all the parts in your picture... my Bentley for the AAZ seems to alude to this setup on all AAZs including the 93... but there are often regional variations.
Vince