Capture of one from a 0 to 90 blast on the street. Just a little food for thought....


http://www.dieselplace.com/forum/uploads/2Z5_Burst.JPG

Ummm...


http://www.dieselplace.com/forum/uploads/342_ubb1.jpg

You've never heard of bursting? Common when stacking big boxes.

It is a joke, just wanted to post that picture. lol http://www.dieselplace.com/forum/smileys/HiHi.gif

That is a good one.... http://www.dieselplace.com/forum/smileys/HiHi.gif


Maybe the bunny knows how to fix it. http://www.dieselplace.com/forum/smileys/Embarrased.gif

Be very very quiet we're hunting "Bursts". http://www.dieselplace.com/forum/smileys/HiHi.gif


What gear?

That was 5th gear, about 85 MPH when she stumbled. It does not always do it but I got lucky and captured it on this run.


Of course I don't know if I should call it lucky. http://www.dieselplace.com/forum/smileys/Disapprove.gif

Brandon,


Thanks for sharing! I had some stacks burst, on a load test on the dyno. The operator $hit his pants! http://www.dieselplace.com/forum/smileys/HiHi.gif


Of course I forgot to warn him that it might burst and he had no idea what the hell happened until I told him. http://www.dieselplace.com/forum/smileys/Embarrased.gif


Scary!

Brandon,


Thanks for sharing! I had some stacks burst, on a load test on the dyno. The operator $hit his pants! http://www.dieselplace.com/forum/smileys/HiHi.gif


Of course I forgot to warn him that it might burst and he had no idea what the hell happened until I told him. http://www.dieselplace.com/forum/smileys/Embarrased.gif


Scary!





Was he 'Trippin out ' a little?http://www.dieselplace.com/forum/smileys/Big Smile.gif

Brandon,


Are you running a pressure box ?????????


Or does something you have increase rail pressure ??????


Just wondering aloud .............http://www.dieselplace.com/forum/smileys/Embarrased.gif





Thttp://www.dieselplace.com/forum/smileys/Clown.gifNYEdited by: GMC-2002-Dmax

What did you use to capture the snapshot?

OK forgive the stupidity, but what is a burst? I'm fairly new to diesel performance so I'm not that educated yethttp://www.dieselplace.com/forum/smileys/Embarrased.gif

The conclusion on a "burst " is the fuel system is in adequate in suppling fuel or the programming or performance box has gone beyond the fuel delivery system either by fuel rail pressure control valve returning to much fuel or has gone past the injector duty cycle.


I would like to see if a fix is in order as I know or can feel more power in using different configuration with what I have .


Let the games begin.





Mac

Brandon,


Are you running a pressure box ?????????


Or does something you have increase rail pressure ??????


Just wondering aloud .............http://www.dieselplace.com/forum/smileys/Embarrased.gif





Thttp://www.dieselplace.com/forum/smileys/Clown.gifNY





No pressure box has been used on my rig, I never did trust them. Pretty weird pressure spike as it begins to oscillate for sure.

What did you use to capture the snapshot?


I used the Tech II. I don't know if there are any other tools that would allow you to do so as well.

Actual recorded rail pressure exceeds desired rail pressure by almost 3000 psi...........


Seems the fuel pressure was adequate..........maybe the pulse was too long on the injector as Mac said..........


Are you running a lift pump with the MEGA ?????? How much pressure ??????

Comp 140 GPH @ 12 PSI.


http://www.dieselplace.com/forum/uploads/DSC02354_Medium.JPG

Damn, that looks like a New York freeway under therehttp://www.dieselplace.com/forum/smileys/Big Smile.gif

Welcome to spaghetti junction! http://www.dieselplace.com/forum/smileys/Embarrased.gif

Actual recorded rail pressure exceeds desired rail pressure by almost 3000 psi...........


Seems the fuel pressure was adequate..........maybe the pulse was too long on the injector as Mac said..........


Are you running a lift pump with the MEGA ?????? How much pressure ??????





Remember the Tech 2 data is lagging behind what the motor is actually doing. IMHO the Tech 2 "recorded" is up over the "desired" because of the burst. The PCM saw the burst and shut down the fuel pressure, it takes a small amount of time for the fuel system to complete the task.


On Edit: Look carefully at the graph before the burst. The "actual" is below the "desired" all the way up to the spike at the burst. Just my humble observation. http://www.dieselplace.com/forum/smileys/Embarrased.gifEdited by: Trippin

That's why I am not good with graph's...........http://www.dieselplace.com/forum/smileys/Embarrased.gif


I barely passed Blue Print reading in TECH SCHOOL......http://www.dieselplace.com/forum/smileys/HiHi.gif


Don't ask me to follow directions.............http://www.dieselplace.com/forum/smileys/HiHi.gif


THANKS................


Thttp://www.dieselplace.com/forum/smileys/Embarrased.gifNY

oh!!! It's sooo cuuuute!http://www.dieselplace.com/forum/smileys/HiHi.gif

One thing that I've typically seen accompany any "burst" is an instantaneous jaunt to approx 26,000 psi...





Now if you really want to open a can of worms, you can typically FEEL little mini bursts or misfires when running on the dyno. I used to blame the Superflow control PID's, but it seems to be a Duramax anomoly...

One thing that I've typically seen accompany any "burst" is an instantaneous jaunt to approx 26,000 psi...





Now if you really want to open a can of worms, you can typically FEEL little mini bursts or misfires when running on the dyno. I used to blame the Superflow control PID's, but it seems to be a Duramax anomoly...


John,


When I run a stack, say Quad on 110 and Edge on 5 (see signature) I can feel "mini misses" in 5th under full throttle. Could that qualify as mini bursts ?

Could be, but I can't be sure.





Personally, I don't stack, nor do I believe in it. Sure it makes another 20 or so HP, but you are throwing TONS of fuel into it way past the point of diminishing returns on combustion efficiency. 'nother can-o-worms...

so is there a consensus on curing the bursting ? what options are there to fix it or are there any ?

Looks like a duty cycle problem, but not with the injectors themselves but with the driver in the ECM. Without the injector demand from the rail, the pressure spikes till the ECM corrects.

If it was injector duty cycle, you would loose one or two at a time. Now that might be what is happening during the "mini-bursts" you are feeling.

Monitoring pulse voltage to the injectors would be interesting.

the best i have done so far with out the "bursts" is to have the low boost fuel adj. down to one and i have my d-mizer all the way down. i can get the hjat on 5 and the quad on 215. ran real good friday night. still tweeking!!!