setting injector pump timing by ear

[30dodgeboy]

Yes it is harder to pull than push back in, it will go in on its own if not held pulled out.

I measured my pump pressure:
13psi @ 900 engine RPM
25psi @ 1500
35psi @ 2000
72 psi @ 4000

I increased it by tapping down that plug, but have the pressure now a bit too high. Think I have the marbles sound at certain engine speeds & throttle settings. Sometimes it sounds like a gasser with a wicked detonation problem. The cold start handle now pulls out easier with the engine running.

[30dodgeboy]

UPDATE:

I lowered the pump pressure by removing the cartridge and tapping in the other direction from the bottom side. Then re-installed the cartridge and measured the pressure. A bit low so I very carefully raised it, getting 35psi at 900rpm and 95psi at 3000rpm (crankshaft speed). Marbles sound went away. Cold start handle still pulls easier when engine is running than not running, and stays out on it own yet. Performed this change in the middle of a tank of fuel, but did notice an increase in mileage. At the end of that tankful, the mileage was calculated - mileage increased from a consistent 38mpg to 42mpg for that tankfull. Will measure the mileage at the end of this tank of fuel, and I suspect it will be in the 45mpg range.

[30dodgeboy]

I see the timing advance is working when using my timing light with the timing adapter. It changes the timing at the slightest increase in engine speed, but above a certain RPM the TDC mark 'disappears'. I suspect the piezoelectric unit is picking up some other vibration and falsely triggering the light. Anyone else ever had that happen?

[Quantum-man]

I see the timing advance is working when using my timing light with the timing adapter. It changes the timing at the slightest increase in engine speed, but above a certain RPM the TDC mark 'disappears'. I suspect the piezoelectric unit is picking up some other vibration and falsely triggering the light. Anyone else ever had that happen?

The piezo can be faulty. However, you could try cleaning the fuel line.
Rotate it perhaps.
You could try a position further back away from the injector. It could be reflections.
Try a different line...
"Yes" in answer to your question

[30dodgeboy]

The piezo can be faulty. However, you could try cleaning the fuel line.
Rotate it perhaps.
You could try a position further back away from the injector. It could be reflections.
Try a different line...
"Yes" in answer to your question

I cleaned the line with sandpaper, because it read very erratically at first due to the rust layer cushion.

Next time I will try rotating it as well as moving it to a different position or line.

My timing adapter is a MAC tools brand if that makes any difference.

Thank you for the input!

[Fatmobile]

It's possible all the timing marks are just outside the timing window.
http://www.vwdiesel.net/forum/index.php ... #msg327627
Once the block goes out of view there is nothing to point at.
I'm going to make some more marks past the block to see.

[30dodgeboy]

THANK YOU for that link!

It seems that thread will cover what I have experienced myself - I will read it in detail as soon as I have a little free time.

The timing marks were certainly outside the window, as the visible part of the flywheel appeared to "jump" to a different part of the flywheel. At idle, the marks were nice and steady. As I increased the engine speed very slowly the marks would move, indicating the timing advance was functioning. At a certain point the visible portion of the flywheel jumped to a different part, so the marks were visible and then just gone. Once the marks were gone, I could tell I was looking at a different part of the flywheel, as one of the 12pt 9mm heads of the flywheel screws would instantly appear as the timing mark disappeared - one or the other was visible, never both. It was not as if they moved at a consistent rate and simply moved out of view.

I know the timing light is good, I use it on my race cars.

THANK YOU again for that link!

[Fatmobile]

I think that while the timing is changing it might be hard to calculate and that causes it to jump around.
And while it's staying near the same RPM it shows up more steady.