Cold Weather Rail Pressures - Competition Diesel.Com

Red_Rattler · 11-28-2012, 06:34 PM

This is something that's always bugged me since I got a rail pressure gauge years ago and I'm finally gonna ask about it.

So when it's 50 and above he truck at cruise speed like on the hwy the rail pressure is normal 10k - 15k but when it's 49 degrees or lower its at 7500 - 10k under the same conditions. Get on the throttle it jumps right to demanded rail pressure like normal though. Is this for just cold weather protection or what's the reason behind the "dual" factory tuning? I don't know if this is just 03-04 specific stuff again? Any input would be appreciated.

07redsled · 11-28-2012, 06:37 PM

my 04 does the same thing ... yet my dad 06 doesnt , guess us 03-04 guys just get the shaft ....

estrada5.9 · 11-28-2012, 06:41 PM

Yep same issue here, normal.

duck_04 · 11-28-2012, 06:43 PM

Quote:

Originally Posted by estrada5.9

Yep same issue here, normal.

I think he knows it's normal, just wondering what the reasoning behind the tuning that causes it.

94ttss · 11-28-2012, 09:49 PM

I've been asking the same thing for years, really sucks with big sticks.

Red_Rattler · 11-28-2012, 09:54 PM

Just another mystery EFI could shed light on... I wonder if UDC would be able to see both maps or...?

homewrecker · 11-28-2012, 10:06 PM

I would be willing to bet it's an emission thing built into the oem tuning.

Sent from Razr Maxx

estrada5.9 · 11-28-2012, 10:21 PM

Quote:

Originally Posted by Red_Rattler

Just another mystery EFI could shed light on... I wonder if UDC would be able to see both maps or...?

Hmm I am going to start playing with UDC soon. Sure would be grand to fix that.

LReiff · 11-28-2012, 11:14 PM

Efi allows temp multiplier tables to be adjusted. Doubtful if udc does the same.

monster50iii · 11-29-2012, 08:58 PM

I would bet they do it to help build more heat. I've noticed that with rp4 I cruise with rp at 20k instead of 14.5k. But when its cold itll be at 20k cruising and believe it or not my ecm must notice this because my cruising rp will SLOWLY drop down to 10-12k and stay there till I shut the truck off. Shut the truck off and start it back up and rp jumps right up to 20k for a while again.

Red_Rattler · 11-29-2012, 09:22 PM

cruising at 20k?! holy schitnanigians

monster50iii · 11-29-2012, 09:44 PM

yep! I think it puts the 04.5+ rp settings into the ecm because when I go to rp4 I even idle at 7-8k instead of 5k.

MufflerBearing · 11-30-2012, 05:28 AM

Mine stay right at about 7500 at idle. Stock and with the.S06 Rp on level 3

11-28-2012, 06:34 PM	#1
Red_Rattler Name: Red_Rattler Title: High Tech Redneck Status: Not Here Join Date: Nov 2007 Location: Columbus, WI Member`s Gallery Posts: 2,090	Cold Weather Rail Pressures This is something that's always bugged me since I got a rail pressure gauge years ago and I'm finally gonna ask about it. So when it's 50 and above he truck at cruise speed like on the hwy the rail pressure is normal 10k - 15k but when it's 49 degrees or lower its at 7500 - 10k under the same conditions. Get on the throttle it jumps right to demanded rail pressure like normal though. Is this for just cold weather protection or what's the reason behind the "dual" factory tuning? I don't know if this is just 03-04 specific stuff again? Any input would be appreciated. __________________ 03 Red 2500 4x4 QuadCab Handshaker HO, Kore Recon Kit, Smarty REVO, Banks Techni Cooler, K&NFIPK, MBRP Cool Duals, AirDog II 165.... 95 2500 4x4 Ext Cab Handshaker "BUCKN' BADGER" Ducky Fuel Injection Last edited by Red_Rattler; 11-28-2012 at 06:35 PM.

11-28-2012, 06:41 PM	#3
estrada5.9 Name: estrada5.9 Title: Too Much Time Status: Not Here Join Date: Feb 2007 Location: Williston, ND Member`s Gallery Posts: 1,955	Yep same issue here, normal. __________________ 98 QCLB 10 CCSB

11-28-2012, 09:49 PM	#5
94ttss Name: 94ttss Title: Too Much Time Status: Not Here Join Date: Jul 2006 Location: New Jersey Member`s Gallery Posts: 676	I've been asking the same thing for years, really sucks with big sticks. __________________ Kai 2002 F-350 CC/SB 4x4 5.9 Cummins Common Rail BTS 4R100 Evil Twin Dual CP3 Sticks by F1 Twins by Me, E.D, and CompTurbo Smarty Mumau Diesel My Pics

11-28-2012, 09:54 PM	#6
Red_Rattler Name: Red_Rattler Title: High Tech Redneck Status: Not Here Join Date: Nov 2007 Location: Columbus, WI Member`s Gallery Posts: 2,090	Just another mystery EFI could shed light on... I wonder if UDC would be able to see both maps or...? __________________ 03 Red 2500 4x4 QuadCab Handshaker HO, Kore Recon Kit, Smarty REVO, Banks Techni Cooler, K&NFIPK, MBRP Cool Duals, AirDog II 165.... 95 2500 4x4 Ext Cab Handshaker "BUCKN' BADGER" Ducky Fuel Injection

11-28-2012, 10:06 PM	#7
homewrecker Name: homewrecker Title: gear jammer Status: Not Here Join Date: Oct 2007 Location: Statesville, N.C. Member`s Gallery Posts: 2,137	I would be willing to bet it's an emission thing built into the oem tuning. Sent from Razr Maxx __________________ 05 ram 3500 4x4 QC dually SOLD 05 2500 QC Laramie sport Garmon built tranny FI 63/68/.91 ETR-HO S480/92/1.25 dual pumps 105% injectors

11-28-2012, 06:37 PM	#2
07redsled Name: 07redsled Title: cumm-a-part owner Status: Not Here Join Date: Jan 2010 Location: PA Member`s Gallery Posts: 437	my 04 does the same thing ... yet my dad 06 doesnt , guess us 03-04 guys just get the shaft ....

11-29-2012, 08:58 PM	#10
monster50iii Name: monster50iii Title: Diesel Enthusiast Status: Not Here Join Date: Oct 2011 Location: Medford, MN Member`s Gallery Posts: 141	I would bet they do it to help build more heat. I've noticed that with rp4 I cruise with rp at 20k instead of 14.5k. But when its cold itll be at 20k cruising and believe it or not my ecm must notice this because my cruising rp will SLOWLY drop down to 10-12k and stay there till I shut the truck off. Shut the truck off and start it back up and rp jumps right up to 20k for a while again. __________________ 2008 LMM - 80% Stix, S&S 10mm cp3, s369sxe

11-29-2012, 09:22 PM	#11
Red_Rattler Name: Red_Rattler Title: High Tech Redneck Status: Not Here Join Date: Nov 2007 Location: Columbus, WI Member`s Gallery Posts: 2,090	cruising at 20k?! holy schitnanigians __________________ 03 Red 2500 4x4 QuadCab Handshaker HO, Kore Recon Kit, Smarty REVO, Banks Techni Cooler, K&NFIPK, MBRP Cool Duals, AirDog II 165.... 95 2500 4x4 Ext Cab Handshaker "BUCKN' BADGER" Ducky Fuel Injection

11-29-2012, 09:44 PM	#12
monster50iii Name: monster50iii Title: Diesel Enthusiast Status: Not Here Join Date: Oct 2011 Location: Medford, MN Member`s Gallery Posts: 141	yep! I think it puts the 04.5+ rp settings into the ecm because when I go to rp4 I even idle at 7-8k instead of 5k. __________________ 2008 LMM - 80% Stix, S&S 10mm cp3, s369sxe

11-30-2012, 05:28 AM	#13
MufflerBearing Name: MufflerBearing Title: Too Much Time Status: Not Here Join Date: Oct 2008 Location: Boyertown, PA Member`s Gallery Posts: 1,188	Mine stay right at about 7500 at idle. Stock and with the.S06 Rp on level 3 __________________ 17' Mega 3500 W/Aisin, 2nd gen swap with billet S468 87' 4runner LS, NV4500, 1 Tons.