Go Back   iRV2 Forums > MOTORHOME FORUMS > MH-General Discussions & Problems
Click Here to Login
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on iRV2
Thread Tools Search this Thread Display Modes
Old 01-03-2012, 02:08 PM   #1
aragu36's Avatar
Join Date: May 2008
Location: san bruno ,ca
Posts: 57
Fuel Pump Alwaya on

I changed my fuel filters and lost prime >
Thats another story
The problem i'm having is the fuel prime is always on or stops for 10-20 seconds and comes on again
its a black box about 6 in long and connects to a 6in round ball via air hose ? I don't know if the pump is broke it just stays on all the time
Any help

PS I think the little black thing is the fuel prime?

CUMMINS ISB 5.9 275 hp
Allison MT 643
aragu36 is offline   Reply With Quote
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!

Old 01-03-2012, 03:01 PM   #2
Senior Member
Join Date: Jun 2007
Posts: 233
I'm thinking that black box you are looking at is a Vacuum pump.
It has nothing to do with the fuel system. It creates vacuum for the heater/air conditioning control and cruise control.
The priming pump that you have is a carter electric pump, and to fill your filters properly, is to turn on your ignition key on and off several times, leaving it on for 30 seconds at a time for the pump to fill up the filters.
Next time try filling the fuel filters with clean fuel before installing them.

sjholt is offline   Reply With Quote
Old 01-03-2012, 03:25 PM   #3
Senior Member
Mr_D's Avatar
Winnebago Owners Club
Solo Rvers Club
iRV2 No Limits Club
Join Date: May 2011
Location: Vancouver, WA
Posts: 31,225
Originally Posted by sjholt View Post
I'm thinking that black box you are looking at is a Vacuum pump.
2009 45' Magna 630 w/Cummins ISX 650 HP/1950 Lbs Ft
Charter Good Sam Lifetime Member, FMCA, SKP
RV'ing since 1957, NRA Benefactor Life, towing '14 CR-V
Mr_D is offline   Reply With Quote
Old 01-04-2012, 11:41 AM   #4
aragu36's Avatar
Join Date: May 2008
Location: san bruno ,ca
Posts: 57
Is it normal for the pump to run constant ?
CUMMINS ISB 5.9 275 hp
Allison MT 643
aragu36 is offline   Reply With Quote
Old 01-04-2012, 12:07 PM   #5
Moderator Emeritus
Mike Canter's Avatar

Join Date: Apr 2008
Location: Freeport, ME
Posts: 4,707
No it is not. On my previous MH I had that problem and found a hose leaking and a leak in a diaphram on a vacuum control unit. You can follow the vacuum lines and pinch them off one at a time and see which ones make it hold vacuum and stops the pump. I would first pinch off the main line coming out of the pump to see if it shuts off or not. Could be the pump is bad. You can also go to a car parts store or Sears and get a vacuum tester which is a small hand pump with a gauge on it. Then you can go around to each vacuum control and hook the below pump up and test it.

Amazon.com: Actron CP7830 Hand Vacuum Pump: Automotive
Mike Canter
"Gunner" USN Retired, Airdale
2004 Monaco Signature 44' Conquest. Detroit 60
Mike Canter is offline   Reply With Quote


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Fuel pump in, however... svdreamer Vintage RV's 21 09-22-2011 08:52 PM
Anyone know where to get aftermarket fuel pump for gas Onan HoRotica Class A Motorhome Discussions 8 05-14-2011 10:40 AM
Save your fuel pump woodyk Workhorse and Chevrolet Chassis Motorhome Forum 1 09-07-2010 04:38 PM
location of engine fuel lift pump lera Alpine Coach Owner's Forum 1 08-30-2010 10:16 AM
Engine Fuel Transfer/Lift Pump Failure Question jetar Alpine Coach Owner's Forum 7 01-13-2007 08:35 AM

» Featured Campgrounds

Reviews provided by

Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 12:30 AM.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2018, vBulletin Solutions, Inc.