M-TDI Audi 80 quattro AHU/LT pump

[8v-of-fury!]

Mine is starting well at 1.15mm, I have not tried the 1.3mm region yet.. Only the upper and lower extremes of advance and retarding.

[rbremiller]

I backed the timing off again and set it to smoothest & most responsive 'by ear'. I installed an AHU outlet bolt which is a pressure valve and not just an overflow orifice. The engine seems quieter and smoother with that change. I mean it runs beautifully. The 'by ear' pump setting was .80mm when I checked it. Go figure. I bumped it up to .85mm and I'm going to leave it there for a tankful to check mileage. The lower pump lift setting seems to correlate to a better low end torque I can feel pulling up certain hills. The AHU outlet pressure bolt has a lot to do with how well it runs now. I think a version of this bolt is used in the Rover pumps as well. The break-in oil consumption has diminished to 1qt in 5k. I tried using an ALH pressure regulator but it had a sharp knock from a higher pressure I guess. I could see the adjusting pin was tapped in further than mine.

[8v-of-fury!]

I have set my idle case pressure to about 30psi as of this past week. I was at near 50psi before at idle.. and it was way too much diesel clatter (advance) when cruising no load. I have never tried as low as .80mm. Maybe I will give that a try this weekend.

[snakemaster]

stock 45psi  , if it claters up the rpm , add a washer at the addv right at the cap, this should help

[rbremiller]

I've driven this car with the pump @ .80mm most of the time since I put it on the road. I got the best mileage 47.5 mpg at this setting. I switched back and forth trying to find the sweet spot. I always returned to .80mm as the smoothest running pump position. With this engine/pump set-up; the timing determines where the torque is going to be. Higher pump lift setting puts the torque band at a higher rpm and low end torque suffers. The same thing with timing an older gas car. Lower pump settings result in a smokier start-up when it's very cold and higher settings are almost smoke free. I'm considering an after-glow switch to help minimize it. When I prioritize my needs for this car; fuel mileage, driveability, then comes performance. I'm in this car for the long term.

[rbremiller]

Giles contacted me understandably upset and very insulted by a few of my posts that describe my experience with him. He insists that he disassembled the pump completely and did the gov mod., boost pin mod, and the advance mod. He says he disassembled the entire top. He just sent me(for the first time) calibration specs for my pump he said were made during testing. I have no reason to disbelieve him from the veracity of his statements; nor to let my incorrect information stand. It's very possible I am wrong about him opening up my pump. i apologize to him publicly if my analysis was wrong. He said "I am a Factory Bosch dealer and we have that Yellow paint and use it with all our pumps.  I did put the new Yellow paint on the same marks that were there before as I remember." He asked me to respond publicly to his concerns and queries. That said, I am left with no explanation why my pump doesn't fuel smoothly (jerky. flat spots) under full boost acceleration or why I can't drive it slowly in second gear. I wasn't wrong to expect perfection for the price I paid for the service. Yes the pump runs reliably; starts and idles consistently. If I attempt to accelerate quickly through the gears it has a "flat spot and bucks slightly as it attempts to rev higher. It's been that way since I've driven it no matter the timing or injectors or running it out of a small fuel tank under the hood. It accelerates like a turd to be honest and I've never been completely satisfied with that. Giles has an excellent reputation for building good pumps over the years and has every right to want to defend his good name and work. His anger and feelings of insult for my posts mean nothing next to my disappointment though.
Rich

[8v-of-fury!]

What a guy..

[Toby]

Giles contacted me understandably upset and very insulted by a few of my posts that describe my experience with him.  <snip>  His anger and feelings of insult for my posts mean nothing next to my disappointment though.
Rich

Why not send the pump back for him to take a look at? It seems clear that he is concerned about his rep, so I would expect that he wants to make you a happy customer. Give him a chance to do that.

[rbremiller]

Giles contacted me understandably upset and very insulted by a few of my posts that describe my experience with him.  <snip>  His anger and feelings of insult for my posts mean nothing next to my disappointment though.
Rich

Why not send the pump back for him to take a look at? It seems clear that he is concerned about his rep, so I would expect that he wants to make you a happy customer. Give him a chance to do that.

BTDT. I don't have the time nor the inclination right now. It was foolish for me to publicly mention my difficulty with him.
  On a lighter note the car started beautifully at 2ºf this morning; the pump timing is now at .83mm. I moved it up to .90mm for a day; but it wants to run smoothest with best overall power at .83mm. I keep coming back to it.

[bbob203]

I'm really curious here as to what amount of degrees below TDC your pump is compared to mine. I have mine set at 12 degree btdc and it must be well over 1.45mm at least. It starts cold ok with glowplugs need below 25degrees or so and have white smoke for a minute or so depending on how cold it is.

[rbremiller]

 I cannot explain the huge gap in timing settings people are using. One of my co-workers has a piezo timing light adapter for me. It's a Mac version; uses a 9v battery. I intend to find out where my actual timing is. Once I do that I would like to offer the adapter for others to use to do the same. When it's colder than º20F I have a bit of smoke for 10 seconds or so; it clears quickly holding the throttle at 1500 rpm. The engine runs evenly throughout.

[libbydiesel]

I can explain the huge gap in timing settings in three ways; differences in injector break pressure, differences in camplate profiles and differences in the plunger or dynamic advance that change the crank/pump degree of the fill port closing and the delivery port opening. 

[rbremiller]

Sounds right.

[8v-of-fury!]

I can explain the huge gap in timing settings in three ways; differences in injector break pressure, differences in camplate profiles and differences in the plunger or dynamic advance that change the crank/pump degree of the fill port closing and the delivery port opening. 

Would you care to add more insight as to which level of each would cause what? I mean it is your call and all .

ie. Higher or lower break pressure, steeper ramps and higher lift vs. lesser ramps and lower lift

[libbydiesel]

I believe that higher breaking pressure injectors, less abrupt camplate ramp and later closing of of fill/opening of delivery port would each require a higher lift in order to achieve the same actual timing of injection.