What does the fuel delivery system do when cruising down a steep hill and the rpms are steady at...

RubenS4 · 10-02-2006, 10:22 PM

...around 4000 in 2nd gear? If the engine speed is induced to run at those speeds down hill(foot off the gas pedal) and the pistons are drawing vacuum, are the chambers still running at stoichiametric? Is the fuel system still delivering as though it had a load since air is rushing into the chambers at 4000 rpm? If it does not, what does our fuel system cause the combustion chambers to do at 4000rpm when the throttle plate is closed?

bitjockey (bum) · 10-02-2006, 10:27 PM

Imolavirus@BuehnEngineering · 10-02-2006, 10:42 PM

PSmalls::AnalRetentiveNumbNut · 10-02-2006, 10:43 PM

Having this knowledge has altered my driving style to the point of improving my gas mileage substantially.

EdyJun · 10-02-2006, 10:43 PM

From what I remember the injectors are injecting just not that much. 3% or 3 ms, I think ?

Edy

RubenS4 · 10-02-2006, 10:49 PM

rojodosformula::red · 10-02-2006, 10:59 PM

Will I get deleted? Most likely! · 10-02-2006, 11:08 PM

Spark is still being delivered but there is no fuel until the rpms drop to 1200 or the accelerator is depressed and torque is requested

Will I get deleted? Most likely! · 10-02-2006, 11:08 PM

here

Will I get deleted? Most likely! · 10-02-2006, 11:10 PM

10-02-2006, 10:22 PM	#1
RubenS4 AudiWorld Member Garage is empty, add now Join Date: Jan 2005 Posts: 289	What does the fuel delivery system do when cruising down a steep hill and the rpms are steady at... ...around 4000 in 2nd gear? If the engine speed is induced to run at those speeds down hill(foot off the gas pedal) and the pistons are drawing vacuum, are the chambers still running at stoichiametric? Is the fuel system still delivering as though it had a load since air is rushing into the chambers at 4000 rpm? If it does not, what does our fuel system cause the combustion chambers to do at 4000rpm when the throttle plate is closed?

10-02-2006, 10:27 PM	#2
bitjockey (bum) Member Garage is empty, add now Join Date: Dec 2000 Posts: 14,946	injectors are shut off.

10-02-2006, 10:42 PM	#3
Imolavirus@BuehnEngineering AudiWorld Super User Garage is empty, add now Join Date: Mar 2002 Posts: 17,943	you're saying zero fuel? so no combustion? ummm........ __________________ -Jacob ^^^CLICK SIG FOR BUEHN ENGINEERING WEBSITE^^^ <big><big>Website Here!!!</big></big> <big>Items For Sale</big>

10-02-2006, 10:43 PM	#4
PSmalls::AnalRetentiveNumbNut Member Garage is empty, add now Join Date: Aug 2006 Posts: 2,688	2nd. Thanks to DAP's motronic book for teaching me the art of overrun. Having this knowledge has altered my driving style to the point of improving my gas mileage substantially.

10-02-2006, 10:43 PM	#5
EdyJun AudiWorld Super User Garage is empty, add now Join Date: Dec 2002 Posts: 2,719	If they are really off wouldn't the car turn off? From what I remember the injectors are injecting just not that much. 3% or 3 ms, I think ? Edy __________________ 2000 Audi S4 STG 3 FATS = 3.66 w/ 91 oct AIM: EdyJun 11 September 2001 In their honor. In their memory. <font color="red">---------------------------------------------------------- <u><big> <a href="http://homepage.mac.com/edyjun1/S4/index.htm">EdyJun's S4 Directory (FAQ, DIY, Info, Tips and Help) </a> </big> </u>---------------------------------------------------------- </font>

10-02-2006, 10:49 PM	#6
RubenS4 AudiWorld Member Garage is empty, add now Join Date: Jan 2005 Posts: 289	Got any ideas to what really happens in there under those conditions?

10-02-2006, 10:59 PM	#7
rojodosformula::red Senior Member Garage is empty, add now Join Date: Mar 2004 Posts: 5,879	So basically the motor is just pumping air on the off cycle? __________________ ----------------------------------------- Formula red NSX-T Tein Mono flex coilovers NSX-R chassis bars Dali SS exhaust Dali ram air/ Uni filter/ SS shifter/ Leather Sparco Milanos Volk GT-P wheels CF NSX-R spoiler Viva la please use the classifieds! Riebes Auto Parts in Loomis, CA can suck it. Thanks for the help bitches.

10-02-2006, 11:08 PM	#8
Will I get deleted? Most likely! New Member Garage is empty, add now Join Date: Sep 2006 Posts: 78	The injectors are off. the Engine is spinning due to mechanical coupling Spark is still being delivered but there is no fuel until the rpms drop to 1200 or the accelerator is depressed and torque is requested

10-02-2006, 11:08 PM	#9
Will I get deleted? Most likely! New Member Garage is empty, add now Join Date: Sep 2006 Posts: 78	Yes read my post here

10-02-2006, 11:10 PM	#10
Will I get deleted? Most likely! New Member Garage is empty, add now Join Date: Sep 2006 Posts: 78	That's all the engine is doing when there is fuel, so why would it change where there is no fuel

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode


Discussion Forums: