I started my pump tuning last week end,
first a little back ground info;
the cage was allready removed from the fuel screw.
there was a lot of smoke at low rpm, no boost, moderate to high throttle, very little smoke with boost and/or higher rpm

1st step; turned screw in till it bottomed, then back out 2 turns, run away upon start up.
2nd step; turned in 1 more turn (I think), idle way too high, a blip of the throttle would rev then the rpm would drop very low then rev as if I hit the throttle again (cant have that). Went for a drive... tons of throttle responce! Yhee haa! But... way too much smoke, drivers behind me lost and probly wreckin, I dont know lots of boost but way way too hot.
3rd step; a couple of test drives later and about 1 1/4 turn back out, too much smoke with out boost but then very clean (too clean) as soon as the boost comes on, 18 psig boost, temp under 1100. idle a little too high, still has a rpm surge after letting off the throttle (causing a problum down shifting).
Next step? should I turn the idle stop screw in? or maby adjust the plate on the throttle linkage that contacts the idle stop screw? I am hopeing that the idle adjustment well fix the rpm surge as well as idle speed, allowing me to put more fuel screw back in. I still have pretty low exh temp. I also would like to reduce the low speed smoke, maby turn out the smoke screw on the top of the AFC diaphram cover? As soon as I get the truck running smoothly again should I turn the fuel pin to its richest setting and trim the stop to get full travel? Then maby a timing bump? 366 GSK is sitting on my work bench and will go in soon too.

Thanks!!
Dave

 

When I installed my 3200 GSK I made a mark on the throttle shaft where the spring was pulling the throttle lever - the one inside the pump top.
Then when I re-assembled the pump, I re-indexed the throttle linkage so that the idle screw was ALL the way in and the throttle stop was a business card thickness off the pump.

Can't get the idle lower than that...

After turning up the fuel screw I had to back off to get the idle down to 750.
Now I get a nice puff of smoke when I floor it but it cleans up by 1500 - 1700 and pulls all the way to ~ 3400.

Just wish I had more AIR !!!

 

AFC tuning can make the smoke clear up, like twist the star wheel counter clockwise i believe, smoke screw etc. etc. There is tons and tons of info in the sticky on how to tune the AFC to clear up smoke. hope this helps, Brandon

 

quick update; idle stop adj helped a lot, 1 more turn on the fun screw ;-)

 

My idle screw doesn't want to budge.

 

Did you loosen the locking nut?

 

I hit it with a screw driver and it moved a little but probably not enough.

 

update; put 1 more turn of fuel in. Turned the fuel pin to the fat setting (about 1/4 turn) now I need to turn the idle down a touch more. I am gettin 20# boost, 1125deg and a light grey haze on a long steep hill. I will need to drive it like this for a while. when I get time I will bump the timeing and do the GSK. Should I go for more fuel screw or a fuel pin? hmmm... Looks to me like to go much farther I will need to pull out the check book, 4" pipe and injecters.

 

First thing to do is back out the smoke screw. That will go a long way towards getting rid of the big puff when you first get on it.

 

I still have more smoke than I would like at the bottom 2-3 seconds in 2nd and 3rd gear. The smoke screw is now as far out as it can go, that helped. The PO had the fuel screw (AFC star wheel) bottomed out, I turned it up 2 turns that helped out too. The fuel screw now seems to be coming in at about 10 psig, I may turn it back down a half turn.
I turned the fun screw in 1/2 turn, had to take 1/4 back out. I cant go any farther for now because i am limited by the idle. the lever is still in contact with the stop screw with about 4 threads showing. I cant back it out any further, I will turn it around when I put the 366 spring in. Grinding is a option too. I hope this is entertaining and maby informative to some of us, all comments are very welcome

 

if you want to turn it up more re-index your throttle shaft and switch where the throttle linkage and the return springs are.

 

Sounds like a good idea, Thanks!

 

My low idle only has ~ 1 thread showing.

And if you're getting too much smoke with the smoke screw all the way out - get out the Dremel....
Look inside the AFC top - you'll see a ridge...I took it down ~ 1/2 because I couldn't stop the smoke off idle. Now I've got to get up to 1300 - 1500 rpm before it will smoke when I stomp it.

Check your fuel pin first !!!
My fuel pin was not getting to the highest point.
I mean that the mark on the fuel pin was stopping before the end of the pin.
Once I ground out the AFC ridge my idle dropped ~ 300 rpm and I was able to get 1 more full turn on my power screw.

Now I need more boost and sticks - the mark on the fuel pin doesn't hit the deepest part - even with the star wheel at the bottom.....
Maybe one of those weak VW springs ???
OR - I could cut a turn or two off the stock spring

 

Is this ridge on the top itself or on the piece of metal that holds the diaphragm to the pin?

Thanks, Aaron

 

On the top.
When you turn over the top and look inside you'll see the smoke screw in the middle and around it you can't miss the ridge...