Thing is, we have another factor here. The pump itself may well have only the 8 degrees of engine advance. If you run it with just this, it will carry on and be super retarded at idle.

This is the function of the light load advance cam. It gives us another 7-ish degrees of idle timing advance(3.5-ish pump degrees), which disappears higher in the revs/higher throttle position.

The 'goal' of all of this is to give you a relatively flat 'burn' timing number - at idle, the fuel takes longer to burn due to so little being injected. At high RPM, the burn time takes up a longer number of degrees of crankshaft rotation, so it has to be injected earlier to get most power.

Unplug the cold advance solenoid and leave it unplugged; see if that makes any difference.
Unless you've got another pump to throw in, it might be worth it to use a jerry can for fuel; strap it to the front grill and try it out. Doesn't cost much to try.
If you do try that, let it run and then retard the timing until it sounds right again. Perhaps the advance was stuck or you were getting low fuel pressure or air in the system? I don't know.

 

Cold advance never hoked due to the temp sensor being broke. What I was told that the lever actuating the pin is actually retarding not advancing. Anyway if I press it it does not change anything. I have a spare pump, but tomorrow I will check the injectors, pop presure test them.

 

Yes, it does. The further in the pin is, the more retarded. You should hear a signifigant difference between the furthest out(idle) position and all the way in. Like... massive reduction in clatter and possibly missing/gray smoke.

 

I will mess with it tomorrow, first the injectors, then the pump, might even try swaping different pump. Plus want to replace the cold advance temp sensor so it works, hate when something does not. Might even swap the gp relay and see if it works. So far it is on toggle switch, which is fine, but original is original.

 

Rob another thing. The mixture screw. Why is everyone adding a flats when it only affects the wot? Or is it just mixture screw that affects the whole range? Because if it does affect only wot, then it is pretty useless to add some, as I almost never drive foot to the floor.

 

This is kind of a hard question to answer, because of how the system works. It only affects /full load/ fueling. You may not need your foot to the floor to get full load fueling.
Thing is, our pumps are governed pumps. What happens is the throttle lever changes the spring force on the governor. The governor balances the spring force from the throttle lever with the force from the flyweights which is dependent on RPM.

Effectively, if you are crusing along at a given load(straight road, 55MPH lets say), and you start going up a hill. The engine will start slowing down, the governor will attempt to compensate and add more fuel(Note that it won't /fully/ compensate, which is why you have to give it some extra throttle to maintain speed). Go down a hill and it will remove fuel.

The governor then controls what is called the "metering valve", which controls the total fuel flowing into the actual pumping element. The fuel going into here is going to be divided up among the 8 cyls evenly.

What happens is that fuel from the metering valve will make it's way at the correct time into the plungers which actually squish the fuel and make it squirt out the injector lines.
These plungers will only "open" based on fuel pressure. If only a little fuel is in there, they won't open all the way, and you will only squirt a little fuel when it compresses again.
The "mixture screw" as you called it, controls the maximum amount the plungers can open when there is sufficient fuel from the metering valve.
It effectively controls "maximum fuel per squirt" or maximum fuel per injection event.

Do you need to be foot-to-the-floor to get to this point? No. If you gave it, lets say, 1/8 throttle and then had a heavy load such that the RPM dropped down to 700, the governor would open the metering valve quite far attempting to compensate, more fuel goes into the plungers, opening them until it hits the limit controlled by that screw.


What does all this mean? Adjust the screw 'appropriately'. How do you do that? Go up a hill in high gear(high loading), and floor it. Do you see black smoke behind you? Turn it down a bit. Do you see nothing? Turn it up a bit. You want just a slight haze at maximum fueling. This will keep you from smoking(which reduces fuel economy and increases EGTs), while making sure you have enough fuel to make the most power you can cleanly.

Note that this adjustment only really applies to a non-turbo engine. Once you have a decent turbo on it, you screw it down all the way because at the higher end of the revs you can use /all/ the fuel your pump can possibly put out cleanly. You will then have to control the engine more carefully with your foot at low revs to prevent smoking, or install an aneroid(Hypermax smoke puff limiter) which reduces the maximum fueling until you have boost pressure to burn it cleanly.

 

Well what confuses me, that I do not touch the screw, but changing the timing affects the smoke level in thus way, than retarding it does not smoke at all, idle, wot clean as gasser, more advance, more power but it smokes black at wot or under load at low rpm, but overall performs better than retarded. The amount of fuel that is entering is the same regardless it is advanced or retarded. It just behaves the opposite I would expect. Retarded would be black smoke, not completely burned fuel, advancing it it should clear, of course not advanced too much.

The last advance change it was performing great, three days of sitting and it is way overadvanced, u can hear it doesnt want to rew down low, loves the 2000 and more. What the hell is happening? It starts perfect cold, hot. I disconected all the fuel lines, blew them through, no obstacles. New fuel filter, the lift pump looks new. How the hell can timing change so drastically? I need the timing light.

 

Sounds like the internal advance piston is sticking perhaps? The pump is worn out and needs a rebuild, but you already knew that.

It's stuck in an "advanced" position... If the timing doesn't actually compensate for RPM, you'd have what you see there -- low end sounds advanced, high end sounds retarded(or normal), because of how long the fuel takes to burn.

edit:
I fought with a pump like this for a couple of years. I either had a low end or a high end. Either it would perform nicely from 0-1800 RPM, then start clattering beyond that, or perform good at the high end, but smoke and have low power at the low end.

Finally swapped it out with a random spare pump(I think this may have been a 6.9 reman pump off Craigslist) and hey, things worked a /lot/ better! I had much more dynamic range!

That being said, even once I got my RD2 pump, I was never able to get something that felt 'right' timing wise from 0-3200 RPM until I finally adjusted the light-load cam, messed with the timing screw, and overall just tuned the crap out of it. The problem in my case was that my turbo won't do much of anything until above 1600 RPM, but I do most of my driving in the 1000-1700 range. So having the low-end timing advanced such that I got maximum "NA" power at the low end was crucial... But once you get boost, the key is having it more retarded for maximum performance(I suspect the fuel burns faster too, the air charge is going to be hotter).
Balancing those two aspects was hard enough on a reliable pump, let alone a POS that needs a rebuild.

 

Already talked to Justin, saving for the 90cc pump, but it wont happen until the spring, I have some serious trouble here and need to solve that first before I can play with my toy. I try to swap the spare pump I have and see what happens. Tomorrow is the injector day, I want to get that done so I know at least something is working correct. And I need to build a shed for the truck, the rust starts to bite on the scratched areas.

 

Rob,
Played with the timing some more. The light load advance works, timed it,so when started cold at 10 degrees of ambient temperature it starts without misfire,shake,runs smooth the second it starts. The cold advance disconected. Played with the cam.I have two pumps,both have the cam set way different. The pump the truck has,once the throtle moves it starts retarding. The other pump starts retarding after about 1cm of the throtle move. According the info I have searched,the truck one should be set corect. Moved it to retarding later and the low end is more advanced,but sounds too advanced. Will play with it some more. Still will save for new pump,new injectors nozzles. I have to get the timing light,so I know what the pump does. It runs ok,it can be better I think,but until I get the 90 cc rd pump,cam,injectors and convert to turbo it is fine.