AAZ Pump Tuning

[mm289]

Hi all,

first post here, great site - use the tech resources a lot  , thanks for all your help so far!!

Just resealed an AAZ pump of a TD as it was leaking from the distribution block, everything has gone OK but got a couple of questions which I would appreciate some input on - rebuild petrol engines etc so used to mechanics but it was my first time on a diesel pump.

Engine is in a Vanagon and the install was done by someone else so I don't really know the history. Pump is part no#  0 460 494 286, has a standard boost pin and looks like this



1. Before removal engine was timed at 1.00mm and fuel screw was 1/2 turn short of fully in. On rebuild I have set the timing at both 1.05 and 0.90 and it doesn't feel as if there is as much torque as before - I have tried to increase the fuelling but there is very little adjustment left. The engine runs very clean, hardly any black smoke. Should I have more than 1/2 to 1 turns left on the fuelling screw on a normal pump?

2. I didn't index the throttle mech properly before removal (misread the instructions  ) so on re-assembly it would tick over but no go! Have reset it now so that idle is good and acceleration OK. If I move it one more spline idle is way high so I figure it must be correct where it is - does that sound right?

3. The governor does not have an idle spring, is this correct for an AAZ pump?

4. Just out of interest, when I disassembled the delivery valves in the distribution head, 2 had 1 thick shim and 2 had 2 thinner shims, is this normal?

Will do the governor mod and boost pin next once I have figured out how to up the boost on a K14 turbo, but want to get it running well in "stock" trim first so any thoughts gratefully received.

Thanks.

MM

[burn_your_money]

1) remove the collar that is preventing you from turning the screw in more, but first, see 2

2) Go a spline further and back the max fuel off a bit and see how that feels

3) Normal

4) Normal

[libbydiesel]

All advice here assumes you have a properly functioning EGT gauge and know how to use it.

Definitely remove the collar on the max fuel screw.

Increase the max fuel and drop the idle by adjusting the 'residual pressure' screw (idle stop for the accelerator lever).  Once the residual pressure screw is all the way out and the idle still hangs is when you need to jump a spline.  When you jump a spline and raise the idle up like that, you are jumping it the wrong way.  For more fuel you need to jump it to give more idle adjustment and then adjust the max fuel up. 

[mm289]

Thanks  

Collar is already gone, removed when stripping the pump (what made you think it was there or was it an educated guess )

I will have a look at the throttle when I get a chance to go back in the workshop.

Just as background, I recorded the settings on the fuel screw and didn't change the high or low throttle stops or idle screw. When i first assembled the throttle it would tick over fine but no/very little increase on increasing throttle, so I moved splines until I had normal tickover and what sounded like full acceleration.

To test i went one more spline and had high tickover so backed it off a spline, all done on the original fuel and idle screw settings etc.

EGT is on my list of stuff I need to do before I play with boost pins and turbo so will be adding that to the kit soon

By the way, is Libbydiesel the same as posts on thesamba vanagon forum now and then?

Cheers,

MM

[Gizmoman]

Here is a pic of a boost controller I made from info found on this site.
I have it set to provide 15 lbs and it works great!
Hope this helps and good luck on your pump settings.
My turbo is a K14 as well and the engine is in a Vanagon - well not at the moment

[libbydiesel]

By the way, is Libbydiesel the same as posts on thesamba vanagon forum now and then?

I post on theSamba vanagon forum quite a bit, especially regarding diesel vanagon stuff.