IP adjustment wackyness

[Jettage1]

So I've been working with my TD IP, trying to get the best compromise between no smoke and no power...

I had turned the max fuel screw out a bit, till I got too little "go" for too much pedal, but the smoke was much reduced.  Turned it in maybe 1/8, and things were looking pretty good off boost.  Then last night I pulled the boost pin/diaphragm, made a minor change to the star wheel, and (I thought) put the pin back in pretty much the same spot as I'd had it.

Well.  This morning, started her up, (ran -idled- fine) and went to pull out of my drive (a short steep part).  Almost didn't get out, even floored.  WTF?  I hadn't touched the max fuel since I parked it, and I had thought that the star wheel & boost pin only affected boost fueling parameters...  When I did get to the street, if I kept it floored, eventually I'd hit about 2900 and boost would finally happen and she'd start to accelerate better. 

I don't get it...  Just when I think I'm beginning to understand what does what, the confounded thing does something like this.  Any thoughts?

Thank you...

[Jettage1]

I understand that (I think).  What I don't get is that I didn't change the off-boost fueling (i.e. the max fuel screw) from yesterday afternoon until this morning, yet the car had dramatically less off boost power this morning...so that it was nearly undriveable.  All I did was 1/4 turn clockwise on the star and I think nothing on the pin...

(not that this would be the problem, but I assume that whatever rides on the boost pin will automatically push back out when you re-start the engine after you've had the pin removed...)

[Jettage1]

Ah!  I wondered whether being cold would have any impact.  I guess that's why the stock airbox has a snorkel that goes back by the exhaust manifold - to pick up heat sooner... (I've eliminated mine a while back).

Anyway, sounds like the "minimum" max fuel setting is indicated by where you still have cold engine drivability.  I'll keep testing it cold - & then see how much smoke I have when hot...

Thanks very much - I wish that Bentley or some other pub. would have all of this "hands-on" practical info in one place...  The adjustments are easy - it's the information that's been challenging.  I have yet to find a local mechanic who is both knowledgeable and interested enough to take the time to set it up right - so I'm trying to do it myself. 

[Rabbit TD]

Ah!  I wondered whether being cold would have any impact.  I guess that's why the stock airbox has a snorkel that goes back by the exhaust manifold - to pick up heat sooner... (I've eliminated mine a while back).

Anyway, sounds like the "minimum" max fuel setting is indicated by where you still have cold engine drivability.  I'll keep testing it cold - & then see how much smoke I have when hot...

Thanks very much - I wish that Bentley or some other pub. would have all of this "hands-on" practical info in one place...  The adjustments are easy - it's the information that's been challenging.  I have yet to find a local mechanic who is both knowledgeable and interested enough to take the time to set it up right - so I'm trying to do it myself. 

Your best bet for learning these things is just keep reading here and asking questions and using the search tool.  I don't think there is this much information and opinions with as quick of an acess to it anywhere else around.  I've learned tons of stuff about fuel system and turbo problems here, best place there is.  The problem is though that it is adictive