24 Valve 2nd Gen Dodge Cummins 98.5-02 Discussion of 24 Valve 5.9 Liter Dodge Cummins Diesels with VP44 Injection Pumps
Sponsored by Trailer Plus

Poor fuel mileage?

Thread Tools
 
Search this Thread
 
  #11  
Old 12-05-2010, 01:45 PM
kerley's Avatar
Diesel Enthusiast
Thread Starter
Join Date: Aug 2010
Location: Montgomery, Alabama
Posts: 268
Received 7 Likes on 7 Posts
Default poor fuel mileage

I started tinkering under the hood and pulled my air filter. The filter looked okay but I replaced it anyway. When I removed the air filter I found a rats nest between the air intake and the filter in the oem filter box.

This week we took a 400 mile trip towing my 16 foot Featherlight GN horse trailer. Going I drove mostly freeway 55-60 mph empty. Returning home loaded [one shetland pony for my 5 yo grand daughter] I had some long grades to pull, but maintained 55-65 mph. I averaged 15.5 mpg.

I have 190K on my injectors and am wondering if they need some attention or replacement. I am reluctant to go to a garage as I have not fully recovered from the last rapeing I got. I am sure that I could exchange the injectors myself but attempting the job the first time without some experienced guideance is a little challengeing. I would hate doing the job less than perfect.

Also are there any proven Super Chips that would provide more power/economy that are easy to install and are not so expensive? All my friends on Diesel Bombers have been very helpful to me and I appreciate all your input and advise. I wish I was not so damn old, I think I could have had a lot more fun enjoying the things you folks do. Thank you, Kerley
 
  #12  
Old 12-05-2010, 03:38 PM
24vmatt's Avatar
Diesel Wrench
iTrader: (-1)
Join Date: May 2010
Location: Minnesota
Posts: 671
Received 44 Likes on 40 Posts
Default

"Fuel pressure at Idle is 25 pounds and at wot 19 to 21 pounds".
I been told that 25 at idle is too high, it should be arround 18-19.
25 psi at idle will kill ur vp.
 
The following users liked this post:
kerley (04-22-2014)
  #13  
Old 12-05-2010, 04:53 PM
RAW's Avatar
RAW
RAW is offline
Administrator

iTrader: (1)
Join Date: Aug 2009
Location: Alberta
Posts: 6,218
Received 684 Likes on 549 Posts
Default

I been told that 25 at idle is too high, it should be arround 18-19.
25 psi at idle will kill ur vp.
I've heard both ways on that as well. I have 24/25 at idle, and never go under 21 under WOT. Every time I run into someone that works at a diesel shop I ask them about fuel pressure. They mostly say its fine, and a few say 25 is at the limits. I figure if it works, great! Don't **** with it unless it needs it.
 
The following users liked this post:
kerley (04-22-2014)
  #14  
Old 04-18-2014, 11:58 PM
ench35's Avatar
Newbie
Join Date: Nov 2012
Posts: 2
Likes: 0
Received 1 Like on 1 Post
Default ench35

The air intake is around the right head light and there is a large opening under the passenger side battery then up through the fender to the air filter. If you had a rats nest in the air cleaner box there is a good chance there is some more material in the fender. you might try back flushing the fender well with a water hose. I washed a shop towel out of mine when I flushed mine and needless to say I am getting better mileage. PS>Red Dog recommends 18 PSI max on the lift pump for the 1998 24 valve at idle you might try that also.
 

Last edited by ench35; 04-19-2014 at 12:06 AM.
The following users liked this post:
kerley (04-22-2014)
  #15  
Old 04-22-2014, 09:57 PM
kerley's Avatar
Diesel Enthusiast
Thread Starter
Join Date: Aug 2010
Location: Montgomery, Alabama
Posts: 268
Received 7 Likes on 7 Posts
Default

Thank you all for the honest input. What I finally did was check my Intercooler boots, they looked okay from the top but when I got under and looked at them two were torn. I ordered a set from one of the DB suppliers and I installed them, also I removed the factory air box and ordered a new Donaldson BHAF 42790 and heat shield from another DB supplier. I have to tell you SHE BOOGIES now. I have plenty of power and am very happy with my Cummins. She runs and pulls so much better that I forgot all about the mileage.
 
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Mike0624
1st Generation Dodge Cummins 89-93
5
07-17-2015 09:39 AM
Zachbishop
5.9 Liter CR Dodge Cummins 03-07
3
02-10-2015 10:23 AM
Diesel Bombers
General Diesel Related
0
11-12-2014 08:10 AM
Dirty Offio
Big Rigs & Semis
7
11-04-2014 07:43 PM



Quick Reply: Poor fuel mileage?



All times are GMT -5. The time now is 04:14 AM.