Pump timing

[Barry Nave]

What would happen,once the offset is learned and you move pump to the driver side with out rechecking?
Would the pump just be more advance and the learn vaule still be the same?

[rjwest]

Hope you get an answer,, I messed with mine, and
now can not get the TDCO back to normal.

MHO be carefull....

[Barry Nave]

rjwest
I thought your timing looked good at the point you were able to get it set to.
I was just woundering what would happen if pump was moved.
As timing chain wears and other componets wear the base timing would also change. Maybe not enough.
DB2 pumps dont have the learn but would think with the DS4 that once learn is set this can not change.
So with chain wear pump can be adavance?
I know I have a gear drive but am still thinking what would come about if pump was adavanced say 1mm?
TDC learn should not change and only crank timing would.
Where I'm I going with this?
I can't get the crank,base timing at +8.5 with a learn of -1.95
I do have the +3.5 at -1.95.
My truck use to have a good rattle. After 70K miles on gear drive I had timing checked(just to see how gear drive and timing stayed set, It was still dead on) buy the same guy at dealer that did it when I installed the gear drive.
I asked to see if he could get the +8.5 with the TDC of -1.95
Tried but said it throw a code.
Had him set it back to where it first was but truck sounds different.
Does'nt have as much diesel rattle now but he clams it is set back to where it was.
To have it rechecked (wish now I would of seen the numbers myself) cost to much.
I envy those who can do this.
Just wish I could see those numbers :rolleyes:

[rjwest]

In maine, the -1.8 TDCO was VERY noisy at
start up,

My problem started with messing with the " Laptop Scanner ". I had no desire to advance timing,

But, I did a TDCO Learn ( to see if it worked, so as to report to the forum )

The TDCO went to -2.5 and set codes...

After srewing with it got it to -1.8...
Runs very good, but afraid of long term adverse
affects on engine...



I STILL do not understand the Time set and TDC learn think, Also, I have not been able to get any , so called, gm technicians to explain the pump
timing procedure,


I have given up and seriously considering a New gas truck.....

[Kennedy]

It will have NO effect until you move it past the point where the minimum travel of the stepper motor is passed.

In other words, you might pick up a couple of degrees of base timing, but that is about it.

[Barry Nave]

In maine, the -1.8 TDCO was VERY noisy at
start up,

Maybe I'm so use to the rattle that it's just normal now.
I don't see a problem rjwest,timing looks good at that point.
Been runing my timing set up now,close to 90K miles.

[Barry Nave]

Thanks John
Answers my question smile.gif

[rjwest]

??? may be correct, probably forgot what a " cold " start sounded like..


Brave95 Did not reply in depth to your questions,
as I consider my self totally ignorant of how
the diesel pump works, did not want to misslead
with bad info..

[Barry Nave]

??? may be correct, probably forgot what a " cold " start sounded like..

During a cold start is does really rattle for it has even more advance. It does settal down with in a short time.
Hey,mostly I was talking out loud. Question was not directed toward you but in general.