Internal IP pressure specs

[rabbitman]

"Pressure in pump MUST be 43.5 Psi at 1000 RPM engine "
"Pressure at 2000 Rpm -about 75.4 Psi"

Is this info still correct for a euro spec JP code engine? IDK if they had a different curve/advance spring or if it's the same as US spec.

Mine is:

12psi at 1000rpm
25psi at 2000rpm

And I could tell it was acting funny, the cold start knob makes it clack harder even at rpms like 2000-2500rpm.

I'll assume it is 'til I hear different.

Thanks

[rabbitman]

I'm trying to bump it up some and find that I can't get it over 30-35 psi at 1000rpm. I tapped the little thing in (way further in than on my rabbit) until it stops changing the pressure and it's not high enough.

Normally the rpms rise as the pressure goes up, well twice now I've tapped it in and suddenly a gush of bubbles go from the filter to the IP and the pressure drops 10-15 psi and the rpm's rise? Doesn't make any sense to me.

Should I try the regulator off my parts pump?

[745 turbogreasel]

bubbles go from the filter to the IP

Screams restriction to me...

this was on that other board.

[Quantum TD]

My guess would be bad seals on the pressure regulator, or stuck vanes in the pump.

One or two stuck vanes in the pump will dramatically reduce the pressure potential of the pump.

Also, do you have the correct "OUT" bolt in the pump when testing? If not, the pressures will never get high enough.

[rabbitman]

My guess would be bad seals on the pressure regulator, or stuck vanes in the pump.

One or two stuck vanes in the pump will dramatically reduce the pressure potential of the pump.

Also, do you have the correct "OUT" bolt in the pump when testing? If not, the pressures will never get high enough.

I did change the lower seal and it got me another 5 psi.

I let the IP sit with a ATF/diesel mixture for a couple months so hopefully nothings stuck.

Yes it does have an OUT bolt in it, though I could swap in a different one a see if it changes anything.

[rabbitman]

It's acting weird, I could only get about 38psi at 1000 rpm (engine) but if I rev it to 1500-2000 the pressure will shoot up to around 80 really fast, not linear at all.

I had to retard the static timing because it would inject so soon it would try to stall the engine when I drove, now at idle injection is too retarded and it'll smoke blue/miss. But as soon as I put a load on it it'll still clack real bad.

Any info on whether euro diesels had different spec would be greatly appreciated.

[fatmobile]

 Is the center of the regulator still pushed way down,.. you might have smashed the spring.
 I was going to guess bad o-ring on the regulator,.. that connects right to the front of the pump so would explain high internal pressure breaking past the o-ring and pushing fuel back toward the filter.

 Maybe you need a different regulator,.. I've done that and gotten better results.
Orrr you could try to find another spring.
 I asked the local bosch guy about that regulator spring,.. He said I had to buy a whole regulator.

[Quantum TD]

Well, the specs came from Hagar on the other diesel forum, and I've always questioned whether or not it's actually supposed to be a linear equation. The numbers he provided are not linear, they're logarithmic. That, and the specs are for PUMP rotation, not engine rotation. Pump rotation will be 1/2 engine rotation. So, does that affect your numbers?

[rabbitman]

Well, the specs came from Hagar on the other diesel forum, and I've always questioned whether or not it's actually supposed to be a linear equation. The numbers he provided are not linear, they're logarithmic. That, and the specs are for PUMP rotation, not engine rotation. Pump rotation will be 1/2 engine rotation. So, does that affect your numbers?

If you look at my first post up top, I wrote what hagar wrote which says engine rpm which agrees pretty good with the graph that 745 turbogreasel posted.

I tried my other regulator and the results were not much different. I remember doing this on my rabbit and if I tapped a little too hard the pressure would shoot up to 50-60psi and I'd have to start over, with this one I haven't gotten over 40 yet.

Fatmobile, I start with the center of the regulator flush (zero pressure) and tap it in, it hits 30psi fairly easy but has to go quite a bit more to get 35psi, at 40 the center is about 1/8" down.

[Quantum TD]

Thanks good to know. I've been looking for the tool to fine-adjust it, but most diesel shops don't have it, or only sell it as part of a master kit that costs close to a grand. No thanks.

I just need that tool, and a good computerized advance tach timing light. I've got the piezo pickup transducer already. I'm kinda pumped to try all this, because my MPG blows (38 in a Rabbit Pickup). If I can get it to 43+, I'd be happy. Rebuilt the pump myself, but obviously, it needs calibration.

[rabbitman]

I'm kinda pumped to try all this, because my MPG blows (38 in a Rabbit Pickup). If I can get it to 43+, I'd be happy. Rebuilt the pump myself, but obviously, it needs calibration.

I have to brag a bit. During the winter months I was getting mpg down in the mid 30s but when summer hit it shot up to mid-upper 40s and then I hit my all time best ever, 50.1mpg!!!! I was stoked. I ad about an ounce of lucas injector cleaner every fill up.

Haven't messed with the golf yet today.

[ORCoaster]

If you are reading and quoting Hagar then you must be familiar with the two pull tests he does to determine a decent pump.  2 and 20 lbs at idle and at running speed.  Sounds to me that you may have poor vane pump performance in that it won't get up to pressure until the pump speeds up and throws them out against the internal wall of the pump itself.  May be that it needs a teardown and cleaning.  You did try the solvent method but could it be due for some pump purge in there as a real good boil out. 

I would check to see if the tapping of the regulator hasn't bottomed it out as well.  Double check the O ring, was it the fatter thicker one or did you end up slipping on one of the skinny ones. 

You have to get this pressure thing set at idle as it makes the timing change once the engine starts to wind up.  Dynamic timing is tied to static via pump pressure.  And you are correct that it is not linear.  I think Hagar had two points on the graph and others came in later and showed him different.  And the cold lever advance does not work much above the idle.  2.5 degrees advance I think is what it gives when cold but once the RPMs go up so does the internal pump pressure and the advance is greater than what the lever provides. 

Total advance is 12 degrees?  That is controlled somewhat by the spring accessible from the front cover.  Slip a shim out of there and your advance starts early, and even earlier with the proper colored spring.  Green is least resistive,  I have two pumps and I am lucky enough to have two springs that are on the low end of resistance so I am playing with them and the thickness of shims to get me more advance earlier so when cruising at 50 I have the advance of what I used to get at 65.  That allows me to keep my foot off the gas more and that gets me, to quote hagar, Smileage.

[rabbitman]

Yeah I've read all that stuff, the problem with the pull test is that this IP has an idle up feature that works with the advance so as I pull the handle it idles up making it easier to pull.

I also used a pressure guage which is far more accurate than the the pull test.

[smutts]

And you are correct that it is not linear.

Er, I was suprised how linear mine were, can't remember the results, but they are someplace on the forum if you guys want to look.
If you are worried about the precision adjustment with the hammer, you are right to be, it is ridiculously sensitive. You can use a narrow bolt as a drift, with a nut set to restrict how far the pin can be moved.

  With designers cutting NOx, do later diesel engines have reduced rises in transfer pressure? so would an earlier pressure regulator a good thing? For more power, mpg & NOx?

[Mark(The Miser)UK]

As you can see from the results, the response plotted was near as doesn't matter; linear within the normal working range.  Springs tend to give linear responses within normal ranges, so it makes sense.
Against this ideal could be that the escape[feedback] orifice is circular and so possibly non linear.

Hagar was wrong with his extrapolation. Also note his figures were based on the yellow dot pump, a somewhat unique item, I believe that came about because of govt diesel blend rules, emissions, and Bosch experimental response.

This graph is the corrected version,and I found Hagar's numbers dropped down a little from earlier graphs, but still steeper than the other measurements  for the other pumps.
 
Note how 'my' and  Levi's mirror the gradient 'average' values I extracted from SAE.
I'd like to add that increasing the pump pressure isn't the panacea that people think. 

REasons:
1) Pump pressure  response is still linear for lower pressures.

2)What matters is pump advance response to  changes in RPM.  Again as advance is a spring, it is linear wrt pressure, so as long as  it starts compressing  with rpm increases, it will do as you want.

3)Look at 'My' pump results; the  repaired values now mean that at 710 to 740 idle speed, [where I operate]  the advance lever only advances between 1 and 2 degrees crank. This means that I am wasting 3 to 4 degrees advance that could be used at the top end [not that I ever go there . ]

4) Thus all that the addition pressure does is put additional strain on the pump seals....
 So I may return to lower pump pressures...