1st Gen. Ram - All Topics Discussion for all Dodge Rams prior to 1994. This includes engine, drivetrain and non-drivetrain discussions. Anything prior to 1994 should go in here.

Piston Lift pump pressures

Thread Tools
 
Search this Thread
 
Old Jun 29, 2017 | 05:21 PM
  #1  
Jim5870's Avatar
Thread Starter
Registered User
 
Joined: Feb 2005
Posts: 792
Likes: 30
From: Ontario, CANADA
Piston Lift pump pressures

I was working on a guy's truck, re-sealing the fuel pin.

Noticed he already had a piston lift pump installed.
I hooked up my fuel pressure gauge and it read 17 PSI
He must have gotten a 2nd gen lift pump.
Aren't the VE engines supposed to be around 7 PSI?

Is this safe for the pump?
Reply
Old Jun 29, 2017 | 05:53 PM
  #2  
oliver foster's Avatar
Registered User
15 Year Member
Community Builder
Loved
Community Favorite
 
Joined: Dec 2008
Posts: 7,293
Likes: 2,884
From: vermont
I believe my LPHV lift pump I installed on my RC project ran 12 or 14 PSI when I tested it on the shop floor before I installed it.
It was a year and a half a go though. I could chuck my temporary fuel pressure gauge on it again to check tomorrow.
Much higher than the numbers I remember running and people start talking about pushing the seal out of the front of the pump.

2nd gen lift pumps run 20+ PSI.

A lot of guys here swap out the internal spring on the 2nd gen pump and make it a LPHV pump [low pressure high volume].
Reply
Old Jun 30, 2017 | 11:10 AM
  #3  
cougar's Avatar
Registered User
15 Year Member
Liked
Loved
Community Favorite
 
Joined: Apr 2009
Posts: 3,317
Likes: 485
From: alaska
7 is normal, 10-14 is safe mostly, anything over 16 and you risk pushing the front seal out of the injection pump and putting fuel into the crank case (unless it has been modified for high pressure). A high volume pump isn't really necessary on a VE pump unless you went to a bigger head and large + injectors. If you can maintain a minimum of 4 psi at wide open throttle, you have enough fuel for a VE.
Reply
Old Jun 30, 2017 | 01:15 PM
  #4  
ofelas's Avatar
Registered User
 
Joined: Jan 2015
Posts: 541
Likes: 86
From: Outdoors
17psi will be fine on a decent VE that has been running often.
Reply
Old Jul 1, 2017 | 01:30 AM
  #5  
Jim5870's Avatar
Thread Starter
Registered User
 
Joined: Feb 2005
Posts: 792
Likes: 30
From: Ontario, CANADA
I took the spring out of the pump and cut off one coil from the
wide end of the spring.
Now it runs at 13-14 PSI
Reply
Old Jul 1, 2017 | 07:57 AM
  #6  
mknittle's Avatar
Registered User
 
Joined: Aug 2013
Posts: 4,918
Likes: 603
From: Tulsa, OK
Originally Posted by Jim5870
I took the spring out of the pump and cut off one coil from the
wide end of the spring.
Now it runs at 13-14 PSI
now that's thinking. Reduce the pre-load.
Reply
Old Jul 1, 2017 | 08:20 AM
  #7  
j_martin's Avatar
Registered User
 
Joined: Nov 2011
Posts: 4,479
Likes: 211
From: Isanti, MN
Originally Posted by ofelas
17psi will be fine on a decent VE that has been running often.
Nothing to be gained by pushing the limit on input pressure. Blowing the front seal, however, is tow truck time unless you want to risk serious engine damage.
Reply
Old Jul 2, 2017 | 05:25 PM
  #8  
MrFusion's Avatar
Registered User
 
Joined: Mar 2014
Posts: 1,296
Likes: 308
From: PA near Harrisburg
Mine from THD is running 14-15 PSI at idle.
Reply
Old Jul 2, 2017 | 05:32 PM
  #9  
ofelas's Avatar
Registered User
 
Joined: Jan 2015
Posts: 541
Likes: 86
From: Outdoors
17 psi (let alone 14-15) is pushing the limit ? 😂
I won't even bother to address the "nothing to be gained" remark, uninformed as it is.

I reckon 8psi and 126 rwhp is overkill for an 80 year old 👍🏻
Reply
Old Jul 2, 2017 | 06:10 PM
  #10  
bigragu's Avatar
Registered User
 
Joined: May 2005
Posts: 2,867
Likes: 536
On a clean, fresh fuel filter I've always hovered around 16-18 psi on my piston LP I bought from Cummins back in 2008. There was no talk about springs ratings and this and that. I took the part numbers that Wannadiesel posted originally in the stickies and went to my local Cummins and bought the parts and installed them. Freeway cruising, hovers around 14-15 psi. If I punch the pedal, around 12-13 psi on a new filter.
When it hits 10-11 psi continuously at pedal punch, I start looking at how many miles are on the filter and look up the date I last changed it. It's usually time to swap in a new one.

No problems with the VE seal ever blowing out.
Reply
Old Jul 6, 2017 | 10:15 PM
  #11  
mhuppertz's Avatar
Registered User
20 Year Member
Liked
Loved
Community Favorite
 
Joined: Sep 2004
Posts: 4,053
Likes: 135
From: Tijeras, New Mexico, 7,000ft up
Even with my piston lift pump my fuel pressure drops to nearly zero when I hammer the loud pedal.
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
O.T
3rd Gen High Performance and Accessories (5.9L Only)
6
Sep 18, 2007 12:50 PM
toupee
3rd Gen High Performance and Accessories (5.9L Only)
4
Jun 27, 2007 04:19 PM
CTD99
24 Valve Engine and Drivetrain
13
Aug 23, 2005 10:55 PM
Push Rod
3rd Gen Engine and Drivetrain -> 2003-2007
11
Dec 26, 2002 03:31 PM
BigBlue
24 Valve Engine and Drivetrain
8
Oct 16, 2002 04:58 PM




All times are GMT -5. The time now is 01:22 PM.