|
|
07-15-2010, 09:17 PM
|
#1
|
Moderator Emeritus
Join Date: Jan 2007
Location: Litchfield Park, Arizona
Posts: 10,530
|
How Long do You Wait before Using Fast Idle
Following a cold start of my 400hp ISL, I usually wait a few seconds until I see the oil pressure come up before setting it on fast idle but I'm wondering if that might be too soon. Should I give the engine a full minute or so before kicking on fast idle?
__________________
Rick, Nancy, Peanut & Lola our Westie Dogs & Bailey the Sheltie.
2007 Itasca Ellipse 40FD
|
|
|
|
Join the #1 RV Forum Today - It's Totally Free!
iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!
You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!
|
07-16-2010, 01:44 AM
|
#2
|
Senior Member
Newmar Owners Club
Join Date: May 2007
Location: Somewhere....
Posts: 4,054
|
I kick up the idle as soon as the oil pressure comes up. If it didn't within a few seconds, I'd be shutting it down.
There's no real load on the engine at fast idle, so I don't think there's any reason to wait longer.
joe
__________________
2008 King Aire 4562, Spartan K3(GT) w/ Cummins ISX 600
2014 Jeep Grand Cherokee Overland 5.7L V8 Hemi w/ Blue Ox Aventa LX Tow Bar and baseplate, SMI Air Force One brake
|
|
|
07-16-2010, 08:03 AM
|
#3
|
Senior Member
Join Date: Jul 2005
Location: Pahrump, NV
Posts: 329
|
As soon as there is oil pressure.
|
|
|
07-16-2010, 01:57 PM
|
#4
|
Registered User
Join Date: Feb 2008
Posts: 3,607
|
As long as the oil pressure is not pegged high I put it right up.
John
|
|
|
07-16-2010, 02:56 PM
|
#5
|
Senior Member
Fleetwood Owners Club
Join Date: Aug 2009
Posts: 959
|
There is a known problem happening with that motor with cracked manifolds: Cummins 400hp ISL.
Cummins recommends waiting for a warm-up period before moving and the same before turning it off. If someone has additional details, please post.
Question: Why put the motor to a fast idle? and so quickly?
__________________
Fleetwood Providence 2008 40e
Ford F-350 4x4 Diesel 6.0L 2006
Honda CR-V 2006
|
|
|
07-16-2010, 03:40 PM
|
#6
|
Administrator in Memoriam
Newmar Owners Club Retired Fire Service RVer's Spartan Chassis
Join Date: May 2000
Location: Newark, DE
Posts: 25,898
|
I go to fast idle as soon as the oil pressure comes up. If it's cold, the ECM brings the fast idle up a little slower.
Fast idle=faster air pressure build up.
__________________
Adios, Dirk - '84 Real Lite Truck Camper, '86 Wilderness Cimarron TT, previously 4 years as a fulltimer in a '07 DSDP
|
|
|
07-16-2010, 06:41 PM
|
#7
|
Member
Join Date: Mar 2009
Posts: 34
|
3-4 Minutes at low idle.
|
|
|
07-16-2010, 06:54 PM
|
#8
|
Senior Member
Join Date: Sep 2006
Posts: 1,339
|
This is a question I ask at every major Cummins shop and it is about the only universally commonly answered question. I probably have a record of a couple dozen of all the same answer.
Every time the answer has been: yes DO use fast idle after a cold start AND it is best to go to fast idle AFTER the oil pressure comes up AND the pressure stabilizes.
So there is no exact time delay, just when the pressure needle settles in at the top of the scale. Then, mosey your fingers over to the fast idle button and kick it on. For me this is maybe 15-30 seconds or so, though I never timed it.
__________________
2007 and 7/8ths Newmar Essex 4502
|
|
|
07-16-2010, 07:02 PM
|
#9
|
Member
Solo Rvers Club
Join Date: Jul 2007
Posts: 87
|
the fast idle will help keep gunk from building up in your pipes
while your idling, I've always kicked on the fast idle soon
as I see all my gauges are reading correctly.
|
|
|
08-12-2010, 09:35 PM
|
#10
|
Senior Member
Newmar Owners Club
Join Date: Jul 2010
Location: Hastings, NE
Posts: 399
|
This is great to know....amazing what I learn on this site!
__________________
2005 Newmar Essex 4502
500 HP Cummins ISM
2007 Dodge Ram 4 X 4 (Hemi)
|
|
|
08-13-2010, 03:41 PM
|
#11
|
Senior Member
Damon Owners Club Freightliner Owners Club
Join Date: Mar 2006
Location: North East Texas
Posts: 4,946
|
if its warm i kick it up after oil pressure stabilizes....if i need to recharge the air, if not i let it idle along for a few before departing
if its cold the ecm waits for a few things it does then it will ramp it up well over the high idle speed, in fact it sounds like a jet on takeoff full power
__________________
USN Retired, Life time member of the DAV.
Enjoying the 2008 Damon Tuscany 4056, #3998 no your eyes are fine, there are really 6 slides
2022 F150 King Ranch or 2012 Edge toads
|
|
|
08-14-2010, 08:57 AM
|
#12
|
Moderator Emeritus
Join Date: Jan 2000
Location: West Palm Beach, FL. USA
Posts: 27,563
|
Quote:
This is great to know....amazing what I learn on this site!
|
A word of caution: just because you see it here does not mean it is true. Many of us (myself included) have cherished opinions that we may not have any scientific or engineering evidence to back up, or that may have been true at some point in time but no longer apply to modern engines and systems.
The ECM (computer) in a modern diesel does a pretty good job of setting fuel mixtures and RPMs, including idle, without any assistance from the driver. I nearly always let mine handle the engine management chores.
This remark is not aimed at any particular message or advice - just a caution against embracing everything and anything you "learn" on an internet board.
__________________
Gary Brinck
Former owner of 2004 American Tradition and several other RVs
Home is West Palm Beach, FL
|
|
|
08-14-2010, 09:30 AM
|
#13
|
Registered User
Vintage RV Owners Club Fleetwood Owners Club Ford Super Duty Owner
Join Date: Aug 2009
Posts: 1,275
|
Quote:
Originally Posted by RV Roamer [Gary]
A word of caution: just because you see it here does not mean it is true............
............. just a caution against embracing everything and anything you "learn" on an internet board.
|
I know that I read somewhere, on the Internet, that everything posted there was "truth". I read it on the Internet, so it must be true!!! LOL!!!
Honestly, I have heard people say that--- and mean it! The first time I heard it, about 12 years ago, my mouth dropped open. Sadly, I still hear it- from time to time..........
These are the same people who answer those e-mail from x country who need someone to cash a check for them as that is the only way that untold millions can be accessed.............
Sheila
|
|
|
08-14-2010, 12:00 PM
|
#14
|
Senior Member
Join Date: Sep 2006
Posts: 1,339
|
Quote:
Originally Posted by RV Roamer [Gary]
The ECM (computer) in a modern diesel does a pretty good job of setting fuel mixtures and RPMs, including idle, without any assistance from the driver. I nearly always let mine handle the engine management chores.
|
While the modern ECM does a fantastic job of engine management (i.e. let it do all the work), my ISM ECM does NOT handle or do anything for cold high idle.
Hence, with the consistent advice of a dozen different Cummins shops, kick up the idle manually on cold starts, after oil pressure stabilization and leave up while the rig airs up then go on your merry way letting the ECM handle everything else. I've never looked for this specifically in the Cummins technical documentation, it may be in there (or not).
When a dozen techs start agreeing, I tend to start believing as well. A single tech, like what you read on the internet, is well, take it for what it's worth.
__________________
2007 and 7/8ths Newmar Essex 4502
|
|
|
|
|
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
|
|
Thread Tools |
Search this Thread |
|
|
Display Modes |
Linear Mode
|
Posting Rules
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
HTML code is Off
|
|
|
|
» Recent Discussions |
|
|
|
|
|
|
|
|
|
|
|
|
|