No doubt... :doh: - Ford Powerstroke Diesel Forum
Powerstroke.org is the premier Diesel Truck Forum on the internet. Registered Users do not see the above ads.
Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 02-09-2008, 11:52 AM
International Threat
 

Join Date: May 2006
Location: Elkton, MD
Posts: 13,087
Thanks: 0
Thanked 6 Times in 4 Posts
Feedback Score: 1 reviews
No doubt... :doh:

Truck is pouring white smoke at idle and it's 55 degree's. It's also developed a loud knock over the past 24 hours. Oil may be an issue, already spoke to Marc about it. Injectors or fuel pressure are more likely though.

I have to do 3 things.
Change the oil
Check fuel pressure at idle, and while driving. So I have to assemble a fuel pressure gauge.
Run cylinder contribution/buzz tests.


I got this info from another forum... so this is what I'm going to try and do to check the fuel pressure.
Quote:
Originally Posted by Golfer
How to check my fuel pressure

The fuel path on the 7.3L Super Duty's is horrible...the factory fuel circuit comes from the tank, to the pump, to the filter housing in the valley...

From the filter housing it can go 3 places...back to the tank (through the internal pressure regulator on the drivers side of the filter housing)...or to the FRONT of the drivers side head (nearest #2cyl) or to the REAR of the passenger side head (nearest #7cyl).

Fuel pressure at idle should be ~60psi...+/-10

Turn the engine off, and remove the key from the ignition.

First, locate the filter bowl drain line, it's a metal line, that comes down the front of the pasenger side of the block...approximately 5/16" OD. If you slip a 2-3' section of 5/16" (ID) rubber hose over the metal line, you can drain the fuel into a catch pan without dribbling fuel all over the front axle/driveway, etc...

Second, drain the filter bowl, by turning the yellow lever on the passenger side/rear of the housing...

Now that the filter housing is empty, close the drain valve by returning the yellow lever to it's closed position.

In order to check the fuel pressure at the fuel filter housing, you will first need to locate the Allen head, bronze colored plug on the rear of the filter housing...it's located about halfway down the housing, and slightly towards the drivers side of the truck.

You'll need a 3/16" Allen wrench to loosen the plug.

The plug you removed is a #4 Male Boss (or #4 O-ring) plug.

To install a fuel pressure gauge, you'll need the following fittings.

(1) #4MB-#4MJIC (#4 male boss to #4 male "JIC") ...JIC is simply 'hydraulic speak' for a 1/4" 37degree flared fitting.

(1) #4FJX-#4MJIC90 (#4 female swivel by # 4 male JIC 90 degree fitting)...the 90 degree fitting is needed to allow the hose to not interfere with intercooler & intake piping.

Next, you'll need your hydraulic supplier to make you 40" of rubber fuel hose; one end of the hose will have a 0-100psi (liquid filled) gauge on it, and the other end will need to have a #4FJX (#4 female, JIC, swivel fitting) fitting installed.

It is not necessary to have crimped fittings, regular 'barb' type fittings and hose clamps will be sufficient for the low pressures of our factory fuel system. (~70psi)

Once you have the all the parts together, you can install the #4MB-#4MJIC fitting into the filter housing, followed by the 90 degree fitting, and lastly, the hose & gauge assembly.

No sealants, loctite, or teflon tape are needed on any of the "JIC" or O-ring fittings. When tightening JIC fittings, use two wrenches to prevent damage. DO NOT overtighten JIC (or O-ring) fittings, the flared ends, as well as the O-rings will seal with only moderate torque...typically 1/2 - 3/4 turn after finger tight.

Once all the fittings are tightened, and the fuel bowl drain valve is closed, you can cycle the ignition to power the fuel pump, and circulate fuel. Cycle the key 3-4 times, waiting approx 20 seconds between, to prime the filter bowl.

Check for leaks, at all connections. If a leak is present, an additional 1/8- 1/4 turn should be adequate to stop the leak.

Route the rubber hose to the gauge, away from any moving parts, or electrically conductive components (glow plug relays, batteries, etc) and up through the hood & cowl seam. Gently close the hood and fasten the gauge to the windsheild wiper (or radio antenna, mirror, etc) for short term testing.

Cylce the key, & once you see pressure on the gauge, you can now start the truck.

At idle, normal fuel pressure readings are typically 60psi +/- 10psi.

While driving, under FULL LOAD (uphill, foot to the floor) fuel pressure should remain relatively constant...

In my experience, fuel pressures lower than ~35psi can create a loss of lubrication to the injector...causing the plunger & barrel assembly to gall, as well as a loss of performance.

If your fuel pressure at idle is "good" but under load pressure drops below 35-40psi, you will need to investigate the cause of the low fuel pressure.

Typical causes of low fuel pressure are:
Bad/weak fuel pump (located on the drivers side frame, slightly forward of the drivers
Damaged/worn fuel pressure regulator O-rings. (the factory pressure regulator is on the drivers side of the filter housing, and attaches to the housing with 2, black colored, Torx#27 screws).
Damaged/worn injector O-rings

take care~

Dave
^ Just posted the above to benefit myself when I log back on.
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2  
Old 02-09-2008, 12:10 PM
Slacker



 

Join Date: Dec 2006
Location: Surprise, Arizona
Posts: 17,117
Thanks: 13
Thanked 47 Times in 37 Posts
Feedback Score: 4 reviews
Dang, Marty. Sorry to hear that, bud. Were you doing something when this occurred? Keep us posted.
Reply With Quote Quick reply to this message
  #3  
Old 02-09-2008, 12:13 PM
COME ON...ONE TIME!!


 

Join Date: Sep 2007
Location: Fletcher, NC
Posts: 16,560
Thanks: 57
Thanked 48 Times in 47 Posts
Feedback Score: 0 reviews
Dang marty, that sucks! I hope its nothing serious! I recently replaced my Fuel pump, and I just did the BB mod. I noticed most of my white smoke was diminished. I havent checked Fuel pressure tho. I need to do that BTW....(Note to self) I hope you get it fixed easily and cheap Marty.
Reply With Quote Quick reply to this message
  #4  
Old 02-09-2008, 03:47 PM
International Threat
 

Join Date: May 2006
Location: Elkton, MD
Posts: 13,087
Thanks: 0
Thanked 6 Times in 4 Posts
Feedback Score: 1 reviews
I wasn't do anything and it just started last night, out of no where.

I need to check the fuel pressure still (no place open to get fittings). When it was cold the # 4 and 5 cylinders failed and when it was warmed up # 5 continued to fail. #8 failed previous to today but did not show up tonight.

Injector buzz test was fine - no faults.
Reply With Quote Quick reply to this message
  #5  
Old 02-09-2008, 03:57 PM
The Fat Mod
 
Join Date: Aug 2006
Location: Hickory, NC
Posts: 12,509
Thanks: 0
Thanked 1 Time in 1 Post
Feedback Score: 0 reviews
Good luck with the platinum. Hope it gets back running smoothly for ya.
Reply With Quote Quick reply to this message
  #6  
Old 02-09-2008, 04:01 PM
Desert Shield/Storm Vet

 

Join Date: Dec 2006
Location: Munising, MI.
Posts: 9,092
Thanks: 0
Thanked 1 Time in 1 Post
Feedback Score: 0 reviews
Ouch! Good luck Marty hopefully it won't leave a mark in the wallet!
Reply With Quote Quick reply to this message
  #7  
Old 02-09-2008, 04:14 PM
International Threat
 

Join Date: May 2006
Location: Elkton, MD
Posts: 13,087
Thanks: 0
Thanked 6 Times in 4 Posts
Feedback Score: 1 reviews
Quote:
Originally Posted by vitalidle View Post
Ouch! Good luck Marty hopefully it won't leave a mark in the wallet!
It will lol...
Reply With Quote Quick reply to this message
  #8  
Old 02-09-2008, 08:04 PM
International Threat
 

Join Date: May 2006
Location: Elkton, MD
Posts: 13,087
Thanks: 0
Thanked 6 Times in 4 Posts
Feedback Score: 1 reviews
Well after some testing and searching and in depth talking with Marc...

It's defintely failing injector(s), but the cause has yet to be identified. Most likely low fuel pressure, which I need to test as soon as I can find the various parts to assemble a gauge. I have off Monday so that's when I plan to do it.
Reply With Quote Quick reply to this message
  #9  
Old 02-09-2008, 08:11 PM
Premium Member
 

Join Date: May 2007
Location: Effort/Nanticoke,Pa.
Posts: 5,441
Thanks: 0
Thanked 0 Times in 0 Posts
Feedback Score: 0 reviews
Sorry your having problems Marty, hope ya get it figured out by monday.
Reply With Quote Quick reply to this message
  #10  
Old 02-09-2008, 08:14 PM
Rice Hunter
 

Join Date: Aug 2007
Location: Norfolk,VA...Near the beach
Posts: 4,036
Thanks: 0
Thanked 0 Times in 0 Posts
Feedback Score: 0 reviews
DANG MARTY!! Sorry to hear brother!! I have faith in your knowledge to get her fixed quickly. I just feel yer pain in the Green Backs!!
I'm replying to your post for My Benefit for future referance!
Wish Ya Best My Friend!!

OH.....hope ya still got yer pretty mechanical friend around.
Maybe when ya wake up she will have ya surprised!!
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Ford Powerstroke 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



All times are GMT -8. The time now is 06:11 AM.


Powered by vBulletin® Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Search Engine Optimization by vBSEO 3.6.1
Garage Plus, Vendor Tools vBulletin Plugins by Drive Thru Online, Inc.

vB.Sponsors