Low Power, Poor Fuel Economy - Dodge Cummins Diesel Forum
- HOME - FORUMS - GARAGE - TECH - ARTICLES - CHAT - CLASSIFIEDS - REVIEWS - VIDEOS - MEMBER MAP - STORE - INSURANCE -
- REGISTER - CALENDAR - INFO - SITE HELP - RULES - STAFF - MEMBERSHIP - ADVERTISE - CONTACT US -


Welcome to the Dodge Cummins Diesel Forum, the fastest growing Dodge Diesel Community on the internet.

You are currently viewing our boards as a guest which gives you limited access to view most discussions and access our other features. By joining our free community you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is fast, simple and absolutely free so please, join our community today!

If you have any problems with the registration process or your account login, please contact contact us
Go Back   Dodge Cummins Diesel Forum > 2nd Gen. Dodge Cummins 94-98 12V Forums > 94-98 Powertrain
94-98 Powertrain Discussion of components that are directly involved in the power production and all that is needed to get and keep the truck moving . Engine , Transmission Ect...NO ADVERTISING

CumminsForum.com is the premier Dodge Diesel Truck Forum on the internet. Registered Users do not see the above ads.

Auto Insurance

» Featured Product
Wheel & Tire Center

Closed Thread
 
LinkBack Thread Tools Display Modes
Old 04-14-2010, 08:57 PM   #1 (permalink)
Newbie
 
Join Date: Apr 2008
Posts: 11
Thanks: 2
Thanked 0 Times in 0 Posts
iTrader Score: 0 reviews
Low Power, Poor Fuel Economy

I am new to this forum and I hope that it helps me out. I have a 97 Cummins that I am having some trouble with. It has 240,000 miles on it, and a few aftermarket parts on her. I have a stage 2 AFE air filter, 3K GSK from TST Products, a #4 Fuel Plate (the biggest one they make) also from TST Products, and 4" turbo back exhaust.

Recently I had my injectors tested and they were a little low on opening pressure, 220 bar, so I opted to purchase some new ones hoping that this would solve my lack of power/poor fuel economy problems. I got the 70-90 hp injectors and there was a tiny amount of power gain.

I know that the pickup is not making the power it is suppose to because TST said that with a #4 fuel plate alone, my transmission would be wrecked if it was not upgraded, and well it is not upgraded. And on top of that big fuel plate I have now installed the 70-90 hp injectors? I am at a loss.

I am maybe thinking that the low fuel pressure side of my injector pump is to low, suppsed to be 17-25 psi at idle and 25-35 psi at 2500rpm, or something like that.

Any help is much appreciated.
97 Cummmins is offline   Quick reply to this message
Sponsored Links
Advertisement
 
Old 04-14-2010, 09:01 PM   #2 (permalink)
Diesel Head
 
ykdave's Avatar
 
Join Date: Feb 2008
Location: Yellowknife, NT, Canada
Posts: 10,748
Thanks: 20
Thanked 924 Times in 740 Posts
iTrader Score: 0 reviews
could be low fuel pressure, you want to see low 20s under any condition (though it will run 'ok' into the low teens), 30psi+ would be best.

Have you checked the prefilter and removed the fuel heater?

I would check the timing also. they tend to slip to the retard over time. retarded timing will drastically reduce power and economy
__________________
2007 Laramie 3500, Just breakin in the new engine with a few trinkets
2004.5 3500 600 series 2wd 6spd bone stock, my little rice burner
1997 SLT 2500, 5.5" fabtech, 36x13.5 IROKs, 5x12s, s300, 4kgsk
ykdave is offline   Quick reply to this message
The Following User Says Thank You to ykdave For This Useful Post:
97 Cummmins (04-15-2010)
Old 04-14-2010, 09:03 PM   #3 (permalink)
Diesel Freak
 
WUTNOIZE's Avatar
 
Join Date: Jan 2010
Location: NYC...Staten Island
Posts: 910
Thanks: 14
Thanked 52 Times in 47 Posts
iTrader Score: 0 reviews
what is your fuel pressure?.. your stats are right on pressure...did u try changing your filter and cleaning your prefilter? with out the right presuure you will fall on your face. also make sure your fuel shut off solenoid is in the full up position..
click> Fuel Pre-Filter Cleaning on Ram/Cummins
click> TSB 14-07-96 Rev. A
__________________
1997 3500 Dually 4x4 ,5 spd, 241DHD,410's,#10 Plate,Tuned AFC, Ajustable Boost Elbow, KDP Jigged, , 4" Turbo back, 19.5 Alloy Wheels/245/70R19.5, Level Kit, 5100 Bilsteins,BDD Tracbar/Steer box stab , Poly Bushings, Isspro Guages Pyro-Fuel-Boost1Orig Owner
WUTNOIZE is offline   Quick reply to this message
The Following User Says Thank You to WUTNOIZE For This Useful Post:
97 Cummmins (04-15-2010)
Old 04-15-2010, 11:43 AM   #4 (permalink)
Newbie
 
Join Date: Apr 2008
Posts: 11
Thanks: 2
Thanked 0 Times in 0 Posts
iTrader Score: 0 reviews
I replaced the prefilter about 4,000 miles ago. I also had the injector pump recalibrated about 20,000 miles ago. I clean/replace my filters every 6,000 miles. It is time to clean/replace them again but this problem has been pretty consistant. As for the fuel heater I have never heard of it.

Something I though was a little weird, if the truck idles for long periods of time while warm, like as if I was filling up the fuel tank, the truck has a bunch of power for a few moments then goes back to no power?

Thanks for the posts so fast, I will definately check the fuel shut off solenoid since I have never thought about it! As well as look into the fuel heater.
97 Cummmins is offline   Quick reply to this message
Old 04-15-2010, 03:46 PM   #5 (permalink)
Newbie
 
Join Date: Apr 2008
Posts: 11
Thanks: 2
Thanked 0 Times in 0 Posts
iTrader Score: 0 reviews
Oh, and as for what my fuel pressure is... I don't know. I am a college student and dont really have the funds to just go to a mechanics shop to get it tested. I am pretty mechanically inclined, going for a mechanical engineering degree, and I don't want to buy a tool to do it myself if that is not a possiblity. SO, I'm just looking to get some advice about what it could be. Knowing that the fuel pressure could be a cause I will buy the tools to get the job done.
97 Cummmins is offline   Quick reply to this message
Old 04-15-2010, 07:29 PM   #6 (permalink)
Diesel Head
 
Join Date: Sep 2009
Location: Arapahoe, NC
Posts: 2,217
Thanks: 9
Thanked 298 Times in 266 Posts
iTrader Score: 0 reviews
Here's a budget minded fuel pressure gauge. If you mount it permanently it will pay for itself in not having to change fuel filter until it is required.

http://www.cumminsforum.com/forum/94...-12-valve.html
__________________
'96 Dodge 3500,KDP killed, boost-pyro-trans temp, not stock anymore
'01 Dodge 2500 4X4, EC, LB, 6 speed, FP-pyro-boost,
'97 Chevrolet Suburban, K1500, 4.10 gears
RPegram is offline   Quick reply to this message
Old 04-15-2010, 08:53 PM   #7 (permalink)
Newbie
 
Join Date: Apr 2008
Posts: 11
Thanks: 2
Thanked 0 Times in 0 Posts
iTrader Score: 0 reviews
That is awesome! Thanks.
97 Cummmins is offline   Quick reply to this message
Old 08-17-2011, 12:43 AM   #8 (permalink)
Newbie
 
Join Date: Apr 2008
Posts: 11
Thanks: 2
Thanked 0 Times in 0 Posts
iTrader Score: 0 reviews
I know this is an old thread but I thought I would update. I found what you were talking about ykdave. I purchased a new filter and replaced it however, the old one didn't look too dirty. I still have not found out what my fuel pressure is, however I have replaced the overflow valve, and that did give me an average of +2mpg in town.

The new thing is a bit of smoke out of the tailpipe. I cannot tell if it is white or blue, if it is blue it is a very light shade. I can easily tell the smoke coming out when it is night time and there is a car behind me. At idle, the smoke is clearly visible, and when I take off I can see a smoke trail behind me, not heavily, but noticible. Investigating this I decided to do a compression test on the truck. I know that the cummins usually uses a blow by test, but I found a compression tester for $10 and thought that I would try that.

In doing the compression test I found that every cylinder was around 300psi +/- 10psi or so. I heard that the most important thing is that the cylinders be close together which they were. However, compresson is what makes these things work and if there is not enough compression, all of the fuel will not be burned, which may be the reason for the smoke trail I am seeing.

So, sorry for the long post, my question is; are the numbers for the compression in the cylinder ok, or is that really low? Could this be the reason for the smoke that I am seeing? Low power?

Thanks for the help.
97 Cummmins is offline   Quick reply to this message
Old 08-17-2011, 12:56 AM   #9 (permalink)
Diesel Head
 
ykdave's Avatar
 
Join Date: Feb 2008
Location: Yellowknife, NT, Canada
Posts: 10,748
Thanks: 20
Thanked 924 Times in 740 Posts
iTrader Score: 0 reviews
as you already know, compression numbers (overall) dont really mean much, you are well within the cranking pressure for a good engine and the variance between cylinders is awesome if your only +/- 10psi

If its "hazing" or smoking, i would be looking at f'd injectors or slipped timing
__________________
2007 Laramie 3500, Just breakin in the new engine with a few trinkets
2004.5 3500 600 series 2wd 6spd bone stock, my little rice burner
1997 SLT 2500, 5.5" fabtech, 36x13.5 IROKs, 5x12s, s300, 4kgsk
ykdave is offline   Quick reply to this message
Old 08-17-2011, 03:32 AM   #10 (permalink)
Newbie
 
Join Date: Apr 2008
Posts: 11
Thanks: 2
Thanked 0 Times in 0 Posts
iTrader Score: 0 reviews
Hazing would be the correct word. The injectors are fairly new, a bit over a year now. Also I was a but concerned that the injectors I purchased wend bs so I pulled them about 3 months ago and got them tested. They tested what pressure they opened at and said they were within spec and they didn't leak. I didn't ask anymore questions about the injectors.

I have heard about the slipped timing quite a bit. I suppose that is where I will go next. There are many different write ups on how to check/add timing to the p7100. One of which is a proclaimed 40 minute procedure. Is there a certain one that you would prefer? I have heard that 16* is about the max advance with no head studs, is this correct?

I sure don't mean to be a leach on your brain but I Luke knowledge. Would slipped timing be the cause for these various topics;
1. Changing fuel plates from a #8 to a #4 to a stock plate don't have much affect.
2. When engine is first turned on, even when it is close to 90*, if the throttle is hammered with no load the engine will sputter. Goes away mostly when engine is warm.
3. Even with warm engine, while in gear and idling, if I tap the throttle as if to accelerate moderately and quickly let of of it (I mean on and off the throttle fast), the engine will
die.
4. Changing the fuel plate from factory position to ff position seem to have little affect.
5. I can't really tell anymore that I have 3k gsk installed. I can still wrap the engine up to 3k however, it has no pulling power from about 2500 on up.

Thanks again for all the knowledge.
97 Cummmins is offline   Quick reply to this message
Old 08-17-2011, 03:34 AM   #11 (permalink)
Newbie
 
Join Date: Apr 2008
Posts: 11
Thanks: 2
Thanked 0 Times in 0 Posts
iTrader Score: 0 reviews
Sorry for the various spelling errors, I'm typing with a phone.
97 Cummmins is offline   Quick reply to this message
Old 08-17-2011, 08:14 AM   #12 (permalink)
Diesel Freak
 
WUTNOIZE's Avatar
 
Join Date: Jan 2010
Location: NYC...Staten Island
Posts: 910
Thanks: 14
Thanked 52 Times in 47 Posts
iTrader Score: 0 reviews
Sounds like you need to cheek the line up of the foot onto the throttle plate it could be falling below the plate causing the dead spot.
__________________
1997 3500 Dually 4x4 ,5 spd, 241DHD,410's,#10 Plate,Tuned AFC, Ajustable Boost Elbow, KDP Jigged, , 4" Turbo back, 19.5 Alloy Wheels/245/70R19.5, Level Kit, 5100 Bilsteins,BDD Tracbar/Steer box stab , Poly Bushings, Isspro Guages Pyro-Fuel-Boost1Orig Owner
WUTNOIZE is offline   Quick reply to this message
Sponsored Links
Advertisement
 
Closed Thread

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Dodge Cummins Diesel Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools
Display Modes

Posting Rules
You may post new threads
You may 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 On
Pingbacks are On
Refbacks are On


Powered by vBadvanced CMPS v3.2.2

All times are GMT -4. The time now is 06:08 AM.



Powered by vBulletin® Copyright ©2000 - 2014, vBulletin Solutions, Inc.

SEO by vBSEO 3.3.2