vacuum hose routing question Options

[L-Jet914]

I was installing my new ignition and FI harnesses today and I decided to look back at the vacuum hose routing diagram on Jeff Bowlsby's website. I knew my vacuum hose routing had been modified by whatever technician worked on my father's 74 914 1.8 years ago. I noticed that they teed the vacuum retard side of the vacuum advance into ported vacuum off of the intake plenum. According to the vacuum routing hose diagram, it's supposed to be connected to the rear port of the throttle body (which only gets vacuum after the throttle plate moves off idle). Would there be any reason the technician did this? I will end up rerouting the vacuum hose to the proper location. I'm just curious as to why it was modified for whatever reason. So would my 74 1.8 be considered a early or late 1.8? According to the late diagram and the throttle body that is in the car, the hose should route to the front port instead of the rear port.
The part number on the throttle body in the car 022133067C which fits either a Super Beetle 75-79, 76-83 Bus, or 83-84 Vanagon (two port t-body). According to the PET on AA's website shows two different throttle bodies 022133062L or 022133062S for California spec 1.8L 914s. The Porsche PET does not list a throttle body part number for the 1.8, only the 1.7 and 2.0s. Curious as to why someone would put the wrong part number throttle body on my 914, though it does have the 3 pin throttle position sensor. Port setup would be indicative of late 74 because the required port (front of throttle body pointing toward front of vehicle) is behind the throttle plate.

[wonkipop]

the authorative hose diagrams are here mate. bottom of page in link below.
if i dont say so myself. (IMG:style_emoticons/default/beer.gif)
but i am sure mr. b ( @JeffBowlsby ) will back up my outlandish claims. (IMG:style_emoticons/default/biggrin.gif)

http://www.914world.com/bbs2/index.php?sho...57407&st=40

your dad's car would have originally been set up as an EC-A cali spec.
somewhere along the way its got itself an EC-B throttle body.
thats a good thing.
but someone has not quite hooked it up right.
you are an emissions nerd? you know that? after all you had the low down on the CARB treasure trove documents.

just set it up like an EC-B is meant to be as shown in my vac diagrams.
advance vac can on distributor hooks up to port above (before) throttle plate.
retard vac can hooks up to the port below (beyond) the throttle plate.

it will only run retarded at idle then, good for NOX reduction sitting around in traffic jams etc. but she will run cool, at advance on cruise.

the poor old california EC-As were very crudely made to run at retard while at cruise on highway or freeway to lower NOX - but it meant higher head temps.

forget about all the bullshit about early and late 74 L jets.
its made up stuff after people noticed there were two different set ups.
joining dots the wrong way historically speaking?
there was no early or late L jet set ups in 74.
just CA emission compliant and 49 states (USEPA).
the EC-A is cali and the EC-B is 49 states.
and EC-B is the set up you want to do these days 50 years later if you want to look original - ish.

i blame Dr. 914 sitting down in georgia for the faulty explanation. (IMG:style_emoticons/default/biggrin.gif) (IMG:style_emoticons/default/biggrin.gif) (IMG:style_emoticons/default/biggrin.gif) (IMG:style_emoticons/default/beerchug.gif)
but fair enough.
i mean he had an explanation for the two different set ups.
but it was just a wild guess on his part? (IMG:style_emoticons/default/biggrin.gif) (IMG:style_emoticons/default/beerchug.gif)
but at least he knew there were two set ups. (IMG:style_emoticons/default/beerchug.gif)


the diagram you have posted is wrong. it was a good attempt at one from 20 years ago. but it ain't right. for a start the 74s are not like the 75s. and it appears to be based on a 75 set up and a california 75 set up to be specific. use my diagrams.
they have been confirmed off two original cars. mine and starbears. both 74s like yours.

i might be in far off australia but i out nerd any american nerd. (IMG:style_emoticons/default/biggrin.gif) (IMG:style_emoticons/default/biggrin.gif) (IMG:style_emoticons/default/beer.gif) (IMG:style_emoticons/default/beerchug.gif)

- i've got no real idea on what the hose set up you describe would do but it sure would lead to all sorts of strangeness activating the vac can on the distributor that VW never intended to happen. mostly a form of retarded ignition i suspect.
VW always used vac advance to make the air cooled engines run.
1) smooth. 2) ecomical. 3) stay cool at highway cruise.
thats why you want the vac can advance to hook up to the upper port on the t/b.

the emissions strategy in 1974 was pretty blunt when it came to california.
they just plain disconnected the vac advance side of the can by leaving the hose open and tucked under the inlet manifold and they capped the upper t/b port with a rubber plug or maybe even a t/b that never had the port. i've seen the 75 1.8s and there is no port on the throttle body, but in 74 it may have been as simple as a plug on the port for the california cars.
in any case - even if i was an originality nut case i would not run an EC-A california L jet set up. its so simple not to. you just unplug the port and hook up the hose.

[JeffBowlsby]

Michael is the L-Jet MAN. That diagram on my site is out of date, I just have not had a chance to update it. (IMG:style_emoticons/default/thumb3d.gif)