Swap to larger injectors

[410]

It does sound like you have a fuel starvation issue.  A good way to test your setup is to T in a vacuum gauge at the fuel inlet of the pump.  Under full load you shouldn't see more than 5" of vacuum.  Running a primary fuel pump you should never see any vacuum at the injection pump inlet but like Vanbcguy mentioned, most pumps don't provide enough volume for these injection pumps. 

If you have enough fuel pressure at your injection pump inlet under load then it's time to check the internal pump pressure under load.  this is not as easy.  I made my own pressure tap by drilling through the fuel out bolt to install a pressure gauge.  If you get this far I can mail you mine so you don't have to ruin another one.  Lots of adjustments can be made for optimizing the internal pressure which directly controls dynamic timing. 

[ORCoaster]

I just rebuilt the outbolt I have customized to be able to slide a second inlet collar under it.  I was rebuilding a pump and snapped the solder joint

I run 45 lbs of pressure  at idle  and it ramps to 108 under high revs

[rodpaslow]

I didn't get a chance yesterday to check the lda, I'm now having problems with the shut-off solenoid.  I've got a few I tried yesterday and they all operate about the same.  If the car has been sitting for an hour or so it works just fine.  But if I shut the car off and want to re-start it immediately, it will not start unless I disconnect the valve's electric connection and then re-connect it or fiddle with it until it works.  The other car's I've worked on this should 'click' when power is applied - correct?  Maybe I need a new one.

[theman53]

It is probably the wire not the solenoid.

[libbydiesel]

Have you pulled the stop solenoid?  That is a common place for swarf to build up when the pump is self-machining.

[rodpaslow]

I change the wire thinking it was the wire, but that didn't help, I have to check the lda after work today, so I can pull that at the same time an make sure the inside of it is clean.  I made sure the pin was, but didn't think about the inside, where the pin goes in.

I think, by the sound of what you're telling me, is to get rid of the in-tank pump and regulator in the engine bay and get back to proper setup where the pump pulls it's own fuel.

I just hate to do that, as I have the exact same setup on same, my other car, MK3 only it's a 1.6 td.  It's easy enough to do though...

[ORCoaster]

Solenoids wear some and may have a scraped side to it.  600 grit paper might take it out.  But gunk from the pump does seem to collect at that part. 

[rodpaslow]

I cleaned the inside part of the solenoid as best I could, got it so the center of it was shiny metal, some dirt/maybe oil did come out.  Works like it should now.

Next - I pull the top of the lda and pulled the pin & diaphram out to check to see if the pin extends when or near max throttle or at max throttle.  I watched a video (don't remember if it was a 200 or 300 LR pump) and at a certain throttle point the pin is supposed to come out/extend.  My pump doesn't so there is definitely something not right.  The pin connects to a pivot that extends another little pin on the underside of the top-and moves a bracket of sorts with a bit of a finger.  This finger should move the control lever - is that correct?  also if the lda pin & diaphram are out it should extend the pin, correct?

where is it supposed to catch/push the control lever?

[rodpaslow]

Pictures I've looked at, it looks like the very front plate of control lever (towards front of pump) will push against the finger, moving the lower pin in - pivoting the arm - moving the upper pin against the lda pin.  this is in reverse to when the pump is working properly.



Is it possible to have the throttle linkage too far back so the idle spring in on the wrong position of the control lever (more towards back away from drive end) not as shown above?

[manehfr]

i bet on fuel starvation if LDA is a performance one... if it isnt... than its because you need a good LDA ... looks like the easy way to find them in america is looking for cummins fuel pin... maybe there is something cheap on ebay... or yo may make one by yourself... because looks like they aren't cheap... just take a look on google you will have an idea of how it should be more or less... worst case cenario alot of roll call...

[vanbcguy]

LDA is just a smoke limiter, you can make the same peak fueling even with a crappy LDA pin, you just won't be able to keep the smoke down before the turbo spools.

[rodpaslow]

I actually have a couple pins, the stock LR pin (not bad if it`s turned to steeper side) and one actually 410 gave me when I bought a car from him, it seems to work good as well.  I had it in last and it looks like the pin touched the lda pin after pulling the lid off the pump tonight.  It only went maybe .125 up the pin.  I get 10 to 11 psi at max throttle so it makes sense that the lda pin moves a bit.

[rodpaslow]

I`ve got time this weekend and I`m going to remove the pressure fuel pump in the tank, remove the regulator and have the injector pump pull from the tank itself.  The lda still seems way to stiff to start moving, so I pushed on the little pin down the hole and it seems to have helped free it a bit.  I`m going to do the governor mod and see it that makes any difference as well.  If It`s still not working - pump pressure may be the next thing to check.

[rodpaslow]

I have the top off the pump.  I wanted to make sure where the control lever hits the boost pin finger.


image posting

If the pump is turned up to max fuel, does that affect the lda at all?   just wondering if it's at max, if the lda cannot function?  It seems that once the throttle is full forward the lda won't do much, except keep the throttle from being able to go to full fuel.

I still think my mechanism that functions with the lda boost pin was sticking, and sticking so it was hard to move.  Once past sticking part it was easy to move.  I have it moving easily now.  With this fixed and governor mod & changed fuel system, hopefully my problems will be fixed.

This control lever is quite a bit different from the Vw's   It has an additional pivot at the top, and spring farther below.  Works the same.  I'm amazed that the contol collar from idle to full only moved about 1/8" or so.

[libbydiesel]

It seems that once the throttle is full forward the lda won't do much, except keep the throttle from being able to go to full fuel.

That is exactly what the LDA does.  It prevents the control collar to reach the max fuel position until boost pressure and boost pin rise allowing additional motion based on boost pressure.  I don't know that I would say that 'it doesn't do much'.  I think that preventing off-boost smoke is really beneficial both to my wallet and to the canaries.