Why does it state that some pumps cannot be turned up?

[Dfeland]

Just looking at Dave Fritz's web site and on the TST web site and they state the some pump's cannot be turned up? Why is this and does anyone know what year those pumps would be? Just curious because I can't imagine that our pumps are maxxed out from the factory. Say that it isn't so!

 

[formula]

It's not the pump that's the limiting factor, it's the factory injectors. The VE pump can only supply a limited injection pressure. What happens when you turn up the fuel screw with injectors that are too small is little power increase and added stress on the injector pump. When I put in my PODs I gained quite a bit of power without even adjusting the pump.



Cheers,

Sean

 

[BushWakr - RIP]

I'm going to take a different read on this one formula...

It is true that the stock injectors are a very limiting factor, but the pump (when tweaked) keeps trying to work harder and fights the injector limitations in terms of fuel flow capability.

However, in some cases the pump itself does not try to "work harder" or is limited in how much harder it will work.



Now I've never read or heard an explantion of the factor(s) which seem to make some pumps sensitive (like mine) and others "lazy" so to speak.



This issue was one of the very first things I read when I came onto this site some years back. I would be interested in the theory/facts myself.

As I recall the area affected is the "full fuel screw" adjustment... I may be wrong, but that's the one that sticks out in my mind. .



Just my take on this and I'm always open to other ideas...



Bob.

 

[formula]

I wonder if it may have something to do with sloppy tolerances (from the manufacturer) in the area of the plunger and barrel or the spill port and "regulator ring" (for lack of a better term). If this is the case then only certain engines would be affected. Just a thought. Delivery valves perhaps? hummm... ... I think that it'd be great to take a course on diesel fuel injector pumps. In the meantime, I'll be feeding my brain with reading material on that subject and see what I can come up with.



Cheers,

Sean

 

[BushWakr - RIP]

geeezz formula, your like a dog looking for the LAST porkchop...



go get 'em... ... .



bob

 

[formula]

:-laf porkchop :-laf



Yep, I'm on a mission now. Gloves are off.



Sean

 

[BushWakr - RIP]

Ok grasshopper, you go tear into the literature and records and stuff... .



Me, I'm going to use that ancient wisdom that comes with age and maturity, that inner calm, and..... become ONE with the pump

After that, I'll go ask Piers... ... . hey, no one said I had to do it the hard way did they... :-laf :-laf :-laf



Hey, my mom didn't raise no dumb kids, . . she drown 'em all ... .....

Ok, she mighta missed one or two. .





Bob.

 

[Case500D]

Bob,



ROFLMAO!! It is not how smart you are, just where you get your information1



Jeremy

 

[nascar mark]

LOL, Pork Chop :-laf



It comes down to one of these. A shelf full of pumps. Pull one off randomly and it responds to tweaking, pull another off and its a dog. Pull the pumps apart and try finding what seems to be different and you will scratch your head as they seem to be the same. They can even come from the same batch or run of parts and some will out perform others? Manufactures only test about every 20-25 engines that come off the assembly line at a time as there is some variance between engines and time is also a factor. They are looking for a big difference in temps and hp/ftlbs. One of the things that make you go hmmmm.

 

[Dfeland]

Well I ask becuase I started to fiddle with my pump the other day and lost 3psi , when I turned the fuel screw into the lock collar and moved the ecentric to allow the pin to move. Moved everything back and now its back to 30psi. Surely the poor thing has more in it than that. C'mon now there has to be soemthing that I can do. It does not even smoke any more:--) . I have air and now I seem to have run out of fuel. HELP!!!!!!!!!!!!!

 

[jbolt]

F O R M U L A !!!!! Stop using such big words! Spill port, regulator ring, frugenshaften... ... Geeeeze. Some of us went to public school you know. I need pictures with diagrams and small words in big letters.



Sure would be nice to find a factory manual on the VE pump so I knew what you were talking about. :{

 

[BushWakr - RIP]

jbolt,



You can thumb thru one of my VE pump pic galleries for the general overview of parts/components... we're still working on what might pass as a 'manual'... we are working on this for the guys in here...



bob.

 

[BushWakr - RIP]

I pasted this link in the "... best tips... " forum as well, but thought I'd put the link here as well since this is going in the direction pump internals/components etc. . enjoy



http://www.cs.rochester.edu/u/jag/vw/engine/fi/injpump.html





Bob