Internal pump pressure

[vanbcguy]

The small holes are in the perimeter of the OUT bolt.  Drilling and tapping the center is definitely still on the high pressure side of the bolt.  The hole in the end of the bolt has a small screen in it but it definitely isn't the metering orifice.

[vako]

today after 30 kilometer city cruise my engine started to idle lower than it normally does. so as soon as i got home found 250ml of ATF in the garage and started the car right from ATF bottle. in the begining overflow was quite normal but after atf/diesel fluid got hotter the flow became noticeably less. after running the engine on different revs for few minutes and using up the all 250 ml of fluid car started to idle better, and it kinda smokes less than before. engine is idling way better, twitching at low throttle(when moving in gear) is still there but it seems to become less noticeable. to morrow i will heat up the engine (till the fan cycles once) and then measure overflow volume, if it is somewhere between 500-600ml/90 secs i will leave the pressure regulator alone ( my engine is AAZ and idles ~900) 

and i have 3 more questions  ....

1) what do you think about winn's diesel purge? should i try more atf or  winn's fluid?   

3)can clogged up injectors cause twitching at low revs (only when the car is moving)?

2) what about cleaning injector nozzle mechanically (without damaging it of course), if i take injector apart and clean the nozzle itself....

thats my girl 

[TylerDurden]

I would not open the injectors without having a pop-tester to check the break-pressure and spray pattern.

I would suspect the IP internals as well as the injectors, regarding low RPM erratic running. I would circulate more cleaner.

I use Lubro-Moly Diesel Purge, it's good... not sure about Winns.



I have heard that injection system cleaner is mostly naptha, so I recently ran 500ml naptha mixed with 150ml ATF into the IP as a cleaner, the same as I would with Diesel Purge. It seemed to work pretty well.

[theman53]

I would like to know a number on how low of RPM's. Also what weight of the spacer and flywheel combo there

[vako]

my flywheel weights 17pounds/7.7kgs, as i remember it's it's a bit lighter that vw flwyheel   i also do not have front harmonic balancer, instead i have installed tracker solid pulley, that is way lighter than stock one. i only get some nasty high pitch vibrations somewhere at 1100 revs (i can see external parts resonate only at very very narrow rev range maybe 2-5 revs, it is so narrow that i cant even catch that moment with accel pedal, and happens for a fraction of a second only when i rev the engine up or down). other than that engine works well for 3 years/25 000kms already

 i do not have tachometer i don't know how low was the idle yesterday, but i have laser tach & i will check the revs today.

as for ip internals. i have resealed my pump this winter, and all the internals seemed to be in almost perfect condition, there was no scoring or significant wear inside the pump.  i did the reseal because of the main shaft seal and lda seal. i have not dissasambled the lift pump (which creates the internal pressure) but i'm sure that lift pump is in perfect condition too, as was the rest of the pump    


yesterday i installed clear return line on the pump and there were no signs of bubbles there, even when the car started twitching. so i assume that there is no air problem in the pump.

[745 turbogreasel]

how about fuel restriction further upstream?
I had one car with a  floating   bit of  foil i the tank  give me    a hell of a runaround as when you turned the motor off, it wold fall way from the pickup, and not bother you for hours or weeks.
Also inspect and clean the screen in your out bolt for good luck.

[vako]

small update

today i made more strong alternator bracket and small vibration mentioned above is now gone (after three years of beeing there  ).

then that i checked the overflow.   after heating the car a bit (not till the fan came on, because i have 10 liters in cooling system an it takes almost an hour to heat up properly) i checked the overflow. my car idles 950rpm after getting up to normal temp i got 70-75 ml of diesel in 15 seconds .

according to hagar normal flow is: "Next simple test : The flowtest at idle. ---625 ml in 90 seconds ---you have a good IP. "
Approximately 7 ml / sec, 104 in 15 sec, 208 / 30 sec, 416 / min..

after knocking a bit on the pressure regulator at first i got 80mls and after few attempts of knocking overflow increased to 90ml, and i left it alone (i have moved the regulator pin only 0.2-0.4 milimeters, it is even hard to nitice by eye). but according to the sound dynamic timing has increased a bit and i do not hear any difference between cold start lever pulled out an pushed in, i hope i did not increase the pressure too much  soon i will test drive the car and inform you how it will drive




as for the pickup screen dirt i had removed my tank 2 years ago and it was quite clean, also pickup screen has spherical shape an it is almost impossible to be clogged up from the bottom side :/

[TylerDurden]

80-90ml... really?

I would check the OUT bolt for a plugged screen or orifice.

If the screen is plugged, the IP internal pressure could be too high. More importantly, not enough fuel circulating through the IP will cause it to overheat, since the fuel cools and lubricates the IP internals. That's why there is >10x fuel passing through the IP than is actually used for combustion.

If the screen in the OUT bolt and the orifice are clean,
 check for restrictions in the supply and return lines, by repeating the test to/from a bottle.
 If same output (low), substitute an IN bolt at the output fitting and repeat the test.
 If same output (low), the lift-section of the IP is suspect.
 
 

[vako]

overall it would be 480ml instead of 625 (stated by hagar) in 90 seconds and yes it seems low


i had a test drive few minutes earlier,  diesel clacking seems to become more audible after the adjstment, car pulls well and idles almost flawlessly. and during the test drive twitching on low throttle became less noticeable    but the only thing that i am concerned about is the noise...   when i rev it up above 1500 it seems more noisy that it would be with pulled out cold start lever, and is tarts easier than before  :|

i suspect that i will have to get the pressure measured somehow



p.s. there is no restriction in feed or return lines. but i will check the small filter in out bolt tomorrow

[vako]

this is how much i knocked the pin down, old dust layer is seen very well

[ORCoaster]

You may now need to check the timing.  Remember more pressure more advance.  That is likely why the start lever no longer does anything.  It only puts a few degrees of advance to the pump.  Once the pressure builds during higher revs you may now be advanced to the point of marbles on plate clack.  

Just some thoughts to chew on.


And I just saw the picture come up while posting.  Find a way to measure the pressure, that will be best.  I run a gauge inside the car and can see the change from 48 clear to 100 psi when I really get on it.  So I  know the dynamics of this internal pressure can be pretty large.

Chances are if you tap on the regualtor again it may go to far as you have now broken the friction on it.  If you goe to far you have to remove the whole thing and drive all parts out the bottom and reload from the top and start over.  Don't ask how I know that. 

[bbob203]

the cold start cable advances timing 3 degrees afaik.

[TylerDurden]

2.5^o cam (= 5^o crank.)

[vako]

yes i have the clack so maybe i will have to remove the thing and reload it to the position where it was in the begining i somewhere saw a picture pressure regulator valve disassambly and reseting, but i can not find it anymore :|

how many degrees can fuel pressure advance dynamic timing?


few mminutes ago we did the same thing with my friend's land rover discovery td300 but that car seems to have waaay more sensitive regulator valve, so it clack's like a tractor now

[TylerDurden]

how many degrees can fuel pressure advance dynamic timing?

I can't remember where I saw it and I haven't measured it (yet)... it might be 14^o crank (unless it's a Giles pump, I think he mods the case to allow more advance).