MPS, Rebuilding the MPS Options

[Ron914]

Hello to all who have helped me with this project . @emerygt350 ,@TJB/914, @Superhawk996 , @ChrisFoley , @rjames , @MDTerp
I am in the middle of rebuilding my MPS and have a couple of comments and questions .
First when I opened up the unit I found the most difficult job was removing the rivets holding the two halves together.
When I removed the retainer plate to take out the old diaphragm it was in two pieces .

I needed to take two measurements since I was replacing the stop screw , I needed to measure the the stop screw protrusion into the housing . The instruction sheet sent to me by a member had the measurements he must have made when rebuilding his MPS . His stop screw protrusion was 1.97mm and mine only measured 1.72mm.
His inner/outer screw assembly depth in the old diaphragm measured 6.51mm .
Here's one of my questions ?
when I measured mine I got two measurements depth to inner/outer screw assembly was 4.03
and depth to the washer outside the inner/outer screw assembly was 5.46mm.
Again there is a difference and since mine was never accessed before (epoxy over screw was not disturbed) is the difference in measurements ok and which measurement should I use I will try to attach a photo or two to help with my question.
this one .

I have not touched either of these measurements yet and awaiting any help/comments.
I think it's this one to the washer on diaphragm .

[rjames]

Put the ecu knob back in the middle and adjust only the inner screw counter clockwise until it idles ok. Then turn the screw slowly clockwise to lean it out a bit again until the idle starts hunting and then go back a 1/4 turn at most so it stops hunting. That should put you in the ballpark and allow you to drive the car, assuming everything else is good. Then use the wideband o2 readings to dial it in further.

[Ron914]

Put the ecu knob back in the middle and adjust only the inner screw counter clockwise until it idles ok. Then turn the screw slowly clockwise to lean it out a bit again until the idle starts hunting and then go back a 1/4 turn at most so it stops hunting. That should put you in the ballpark and allow you to drive the car, assuming everything else is good. Then use the wideband o2 readings to dial it in further.

Thanks for the reply . I need to add that I must set my timing still , should I try this considering my timing is not spot on . It's kind of hard to set timing with the car running so rough right now .

[Superhawk996]

I need to add that I must set my timing still , should I try this considering my timing is not spot on . It's kind of hard to set timing with the car running so rough right now .

(IMG:style_emoticons/default/bs.gif)

Set static timing at 7-8 degrees using a multimeter or test lamp. That will always get you close enough to start and run decently without the need to get RPMs up to set & verify full advance. Of course this assumes your dizzy advance isn’t siezed up or non-functional.

Lots of videos of how to set static timing on VW’s on the YouTubez.

If you need help or don’t understand the process after watching a couple videos - we’re here to help (IMG:style_emoticons/default/grouphug.gif)