Engine/Transmission (1998.5 - 2002) what causes surging

[tpruitt]

hey all

i just installed the DD2 with my banks Big Hoss and when i am in cruise control the truck will surge when going up a hill. is there anything that i can do to stop this. i was thinkning about putting the TTPM on but i dont know if that would help. right now i am getting 24mpg so i kind of dont want to trad off boxes.

thanks for the imput

trey

 

[Wiredawg]

I think its caused by....

Tpruit:



I had that problem on my '00 and on my '02. Seemed like the thruck's cruise control wasn't liking the fueling box, so it would engage too hard, surge then catch up with itself. It works better if I turn the power down to level 2 on my PM-3 adjustable.



If your box is adjustable, try turning it down. If not, turn it off when using cruise control.



Wiredawg

 

[Hooty222]

Talk to Banks, there is a fix, at least for the ottomind. I am sure they have or are working on a fix also. I was told by a fello TDR Menber, He says his is fine now. I am waiting to get mine back within a few days... ... ...

 

[snowracer69]

Far as I know there isn't a fix, no matter what box you are using.



I get sea-sick w/ my Comp above 2x2 and w/ the Mach 3's chugging along. On 2x2 or below though, she's rock steady wherever I set it. BTW, you can really see the surge in your boost gauge... it'll jump 4-8 psi when my box is on 3x? or above.

 

[RustyJC]

In control system terminology, the DD2s produce excessive gain (gain = change in output / change in input) in the cruise control system. The same thing is true in the idle control system - thus, the "romp romp" if you let out the clutch at idle.



The cruise control (or idle speed governor) circuitry sees speed drop. Based on the amount of underspeed (road speed or engine speed respectively), it sends a signal to the VP-44 to increase fueling by X%. Due to the bigger DD2 injectors, fueling to the engine actually increases by, let's say, X + 20%. Therefore, the speed (engine or road) increases more than the ECM thought it would, so it chops fuel by what it thinks is Y%. Once again, however, the bigger injectors cut fueling by Y + 20%, so speed overshoots low. The cycle then repeats itself.....



If your truck has a vacuum actuator for the cruise control, put a needle valve in the vacuum line and gradually pinch it down to slow down the actuator response. If, like my truck, your cruise control is electronic, I don't know of a fix.



To eliminate the "romp romp" trying to maneuver a trailer at idle, just touch the throttle pedal enough to bring engine speed above idle - this takes the idle speed governor out of the picture - before engaging the clutch.



Rusty

 

[Tcolesanti]

No known fix for the electronic cruise control trucks? Mine drives me crazy.

 

[JTHosler]

tpruitt,



This is off the subject, but what level is your big hoss kit? I would like to run injectors with mine (level 5).

 

[Texas Diesel]

Best explanation I ever read, good job!!

 

[tpruitt]

mine was level five. Mine was rated for 160hp gains.