LOST JEEPS
http://www.lostjeeps.com/forum/phpBB3/

ORM Concerns
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=5&t=26128		 Page 1 of 1
Author:  litton [ Sat Nov 03, 2007 10:52 am ]
Post subject:  ORM Concerns
The disconnecting of the MAF in order to minimize EGR operation sounds like a great idea...but I do have a concern about unintended consequences of taking such action.

It's my understanding (very limited) that the MAF main function in most applications is to sense the air density and provide input to the fuel management system. If this is correct for our diesel engine, can one run into potential problems when pulling hard through mountains and changing temperatures where the air density dramatically changes?

I understand that there are other sensors that also provide info to the fuel management such as air temp, boost pressure, and etc. but I keep wondering if the MAF controls some other vital function.

Appreciate any input from those you are knnowlegable on the subject....which I definity am not.
Author:  DarbyWalters [ Sat Nov 03, 2007 11:17 am ]
Post subject: 
It is of no concern for a diesel. A diesel runs air thru the engine unimpeeded...no throttle plate...no specific air/fule ratio...no problem. It just adds fuel as needed and air is not "metered" or "controlled" by any means. I know it sounds funny from gasser experience, but it is the way of Diesels. rAIOS CAN GO FROM ~ 5:1 TO ~ 80:1 without any detrimental effects.

The MAF is a single loop controller there solely to tell the EGR when to add dirty/hot/inert units to the cylinder to control combustion temps. This keeps NOx down but increases Particle Matter (PM).
Author:  Joe Romas [ Sat Nov 03, 2007 11:58 am ]
Post subject: 
I've read reports here of better running (fuel mileage too maybe?) with the off road device that fools the ecm over just forgetting to plug the maf back in after off roading :lol: Reading the Bosch diesel handbook for the older computer systems like used on older TDI's when a sensor goes bad the ecm uses other sensors and falls back on a backup "plan B" to keep the engine operable. I suspect the same is true on our crd's with newer Bosch ecm's :wink: If they just needed the maf for egr I think they would have left it off and controlled egr some other way and it's hard to tell what all is being changed :lol:
Author:  Diamond Cut [ Sat Nov 03, 2007 12:26 pm ]
Post subject: 
The MAF functions only in a PID loop for the EGR emissions system, nothing more - if you don't want burned exhaust gasses (- soot, carbon, carbon monoxide, nitrogen, ZERO % OXYGEN -) mixing with clean pure atmospheric air (- 70%nitrogen, 20% oxygen, 10% other stuffium -) as it heads into the cylinders, the MAF IS the troublemaker - even serves as restriction to free air flow into the compressor.

gmctd
Author:  litton [ Sat Nov 03, 2007 7:06 pm ]
Post subject: 
Thanks for the replys....now to pull the plug.
Page 1 of 1 All times are UTC - 5 hours [ DST ]
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
http://www.phpbb.com/