turned pump up

[DeepRoots]

not to go against the grain....
but the fuel we buy is MUCH different than it was in 1983-1994.
As such I feel the timing at factory specs doesn't make any sense.
That is assuming you are using the meter correctly.

I am of the mind, of constantly adjusting the pump until you get it where you want it to be.
For me this probably took 35-40 adjustments before I got the power and fuel economy I sought.

 

[Diesel JD]

not to go against the grain....
but the fuel we buy is MUCH different than it was in 1983-1994.
As such I feel the timing at factory specs doesn't make any sense.
That is assuming you are using the meter correctly.

I am of the mind, of constantly adjusting the pump until you get it where you want it to be.
For me this probably took 35-40 adjustments before I got the power and fuel economy I sought.

Hey...
You are very correct the fuel in 2009 is either ULSD or a homebrew cocktail and as such MUCH lower in BTUS/Unit than 1983 fuel, but the 9.7*BTDC pulse spec and the 0.3 ATDC luminosity spec supposedly adjust for this algebraically. Of course you could go against the grain and say that is horses*** and you may be right but the folks that have used them have had their fuel economy go up and seen an increase in get up and go. Also those were the specs from Europe where they've had this ULSD for many years, or so I am told.

 

[jtate]

from what i can tell by the meter that i have is + is atdc and - is btdc.

 

[Diesel JD]

Hey you should go and have a look at the MT480 on ebay, that is like your meter only with the pointer instead of the digital display. Then see where they are showing ATDC as - and BTDC as +. I really think I may call snapon and see if they have a tech there that remembers the 1480 and can answer this simple yet critical question.

 

[jtate]

i looked at my harmonic balancer today to see if it is the two piece type with the rubber insert that separates the two. couldnt realy tell though. ive seen on other engines that after a period of time the outer ring on the balancer would turn slightly causing the timing to read wrong. i wonder if this could be a issue?

 

[jtate]

Hey you should go and have a look at the MT480 on ebay, that is like your meter only with the pointer instead of the digital display. Then see where they are showing ATDC as - and BTDC as +. I really think I may call snapon and see if they have a tech there that remembers the 1480 and can answer this simple yet critical question.

i looked on ebay and seen the meter, and its definitly showing atdc as - and btdc as +.

 

[Diesel JD]

I'm going to call snapon and see if they have any knowledge of this obsolete tool, I'm danged curious now. I'm soon to be in your same position. I'd hate to be confused. +-0.5 degrees could make a huge difference. That pump timing could be all wonky with the fuel system you have if indeed it is worn out as many of us suspect. I really, really am curious to see how it turns out and where I'm at now.

 

[jtate]

I'm going to call snapon and see if they have any knowledge of this obsolete tool, I'm danged curious now. I'm soon to be in your same position. I'd hate to be confused. +-0.5 degrees could make a huge difference. That pump timing could be all wonky with the fuel system you have if indeed it is worn out as many of us suspect. I really, really am curious to see how it turns out and where I'm at now.

i hope you can find someone at snap-on that can answer this question and you get the meter just like mine, that way im not by myself on this .

 

[jtate]

all i can say is right now with the timing set at +0.5* and the pump turned up 1 flat the truck runs great. now if i retard the timing to -0.5* the truck is just sluggish. i bet if i go and advance (+) the timing a litle bit more i could get extra power out of it, but be right at the rattle mark with the idle advance on.

 

[Diesel JD]

More power to you jtate I'd bet that's more advanced than -0.5 ATDC probably as far as you can go without damaging the glow plugs and other components and making too much black smoke is gonna be good. You'll have to let us know if it gets better fuel economy at +0.5

 

[Diesel JD]

As I reread your posts I think you answered your own question. It looks like your pump is behaving just as it should, they are very advanced at idle and retard as you mash the throttle(at least with a stock timing curve...A DPS or Moose curve *might* be different ) I don't know for sure. You say it was at +2 BTDC before you adjusted it? That would have been too advanced and I know from experience that if you get too far advanced it also runs like s*** cause when I was a newbie and did my head gaskets and replaced my pump I made the gear jump timing advanced two teeth and kept advancing the pump...it was not great to drive like that, God only knows how I didn't break something... but I'm grateful I didn't.

 

[Agnem]

I'd think it would be very easy to ascertain the meaning of the plus or minus, but simply taking a reading, and then advancing the pump a significant amount, taking a reading, and then retarding it a significant amount. The way the numbers go is going to tell you what is going on. As for the timing behavior, yes you are correct. It retards as it speeds up. I know this doesn't make sense to someone used to timing gas engines, but the reason for this is.... in a gas engine, the ignition occurs at an exact moment... when there is a spark. And that spark is generated instantly by a process that never changes. Diesel injection on the other hand, speeds up and slows down with the motor, so an injection event takes longer at slower speeds then it does at higher speeds. The idea is to have the "result" of the event occur at the same point in the cranks rotation every time regardless of speed. The dynamic timing is accomplishing this by compensating for the speed at which the plungers are coming together, and the speed with which the fuel is exiting the nozzle.

 

[jtate]

I'd think it would be very easy to ascertain the meaning of the plus or minus, but simply taking a reading, and then advancing the pump a significant amount, taking a reading, and then retarding it a significant amount. The way the numbers go is going to tell you what is going on.

ive did this and to what the meter is showing, + numbers is advancing and - numbers is retarding. so to be atdc the meter needs to read +0.5, cause at -0.5 the truck is a dog.

 

[Mat J]

thanks mel for the timing info.

Jtate it sounds like you have your timing close to where it should be. honestly it is getting to confusing for me to follow because in your last post you say - is atdc and then you say set the meter at +5 but that wouldnt be correct. If your happy where the truck is at just check the glow plugs to be sure of no pitting and see what happens.