Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   PeachParts Mercedes-Benz Forum > Mercedes-Benz Tech Information and Support > Diesel Discussion

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 03-05-2019, 08:45 AM
nyko46's Avatar
Registered User
 
Join Date: Jan 2004
Location: Rowlett - Texas - USA
Posts: 497
Question Diesel Fuel Pump Fuse Blowing

Very frequent fuel pump fuse blowing in a 1999 Ford Super Duty Turbo Charge 7.3 with over 350 K miles.
Truck was running fine and this past week on a cold day in Texas I left the car running in idle while drinking a cup of coffee and for my surprise when I came out the house to go to work the engine was no longer running.
Checked for the issue and found a 30A fuse blown. Had the fuse replaced and turn the engine on but after around 15 minutes the fuse blow out again.
Suspecting a bad fuel pump I replaced it and the engine ran good again. Left the truck ready to go to work in the next day which as again a very cold day in Texas. For my ugly surprise the same problem returned as it was before: the same fuse blow out again and the are I am with the same problem even with a new pump. I check all wires surrounding the pump but found no sign of fried wires. What makes me lost is why the fuse blow after around 15 minutes after engine is running?
This problem started in a cold morning in Texas and I have no sign of gelling fuel.
Can you help me to get the issue resolved?
Thanks

__________________
Nyck - TX - USA
Reply With Quote
  #2  
Old 03-05-2019, 09:10 AM
Maximan1's Avatar
Registered User
 
Join Date: Sep 2018
Location: Anaheim
Posts: 564
Did you change fuel filters? The pump may be blowing fuses because it is overworked.
__________________
Milan Brown 1979 240D, rebuilt OM617.952 turbo diesel, rebuilt 722.315 transmission (my only daily driver)

Instagram: @maximed93
Reply With Quote
  #3  
Old 03-05-2019, 11:26 AM
Father Of Giants's Avatar
Registered User
 
Join Date: Feb 2017
Location: Newport News, Virginia
Posts: 1,597
you might have a short to ground on the fuel pump power feed wire. Wires can corrode and fray internally. Hook a multimeter up to the fuel pump feed wire wire and shake the wiring, your voltage shouldn't drop or fluctuate at all.

If it does you found your problem.
__________________
1998 Ford Escort ZX2 5 speed - 279,000 miles My Daily

1992 Mercedes 300D 2.5 202,000 - Pure junk
2000 Mercedes E320 Black - 136,000 miles - Needs repair

Don't forget to grease the screw and threads on the spring compressor.
Reply With Quote
  #4  
Old 03-05-2019, 08:00 PM
nyko46's Avatar
Registered User
 
Join Date: Jan 2004
Location: Rowlett - Texas - USA
Posts: 497
Question

Quote:
Originally Posted by Maximan1 View Post
Did you change fuel filters? The pump may be blowing fuses because it is overworked.
The same fuse that protects the pump protect also other devices.
Before changing filters, just to learn more about this car, I would like to isolate the pump from the circuit where the other devices are connected.
With this I mean, keep the pump in use but not powered from the same fuse.
Will the engine work correctly if I power the pump directly to the battery?
I want to do something like that before changing filter.
__________________
Nyck - TX - USA
Reply With Quote
  #5  
Old 03-05-2019, 08:02 PM
nyko46's Avatar
Registered User
 
Join Date: Jan 2004
Location: Rowlett - Texas - USA
Posts: 497
Question

Quote:
Originally Posted by Father Of Giants View Post
you might have a short to ground on the fuel pump power feed wire. Wires can corrode and fray internally. Hook a multimeter up to the fuel pump feed wire wire and shake the wiring, your voltage shouldn't drop or fluctuate at all.

If it does you found your problem.
I checked for short and found nothing.
Can be from other device connected to the same fuse?
__________________
Nyck - TX - USA
Reply With Quote
  #6  
Old 03-05-2019, 08:03 PM
nyko46's Avatar
Registered User
 
Join Date: Jan 2004
Location: Rowlett - Texas - USA
Posts: 497
Question

Quote:
Originally Posted by nyko46 View Post
I checked for short and found nothing.
Can be from other device connected to the same fuse?
According to the diagram the fuel heater is fed by the same fuse.
How would you test the fuel heater?
__________________
Nyck - TX - USA
Reply With Quote
  #7  
Old 03-05-2019, 08:24 PM
Registered User
 
Join Date: Sep 2001
Posts: 2,765
Unplug the heater and see if the fuse stops blowing. If it stops blowing the heater is the problem

Good luck!!!
__________________
"Rudeness is a weak man's imitation of strength" - Eric Hoffer
Reply With Quote
  #8  
Old 03-05-2019, 08:29 PM
Father Of Giants's Avatar
Registered User
 
Join Date: Feb 2017
Location: Newport News, Virginia
Posts: 1,597
Quote:
Originally Posted by nyko46 View Post
According to the diagram the fuel heater is fed by the same fuse.
How would you test the fuel heater?
Check the wiring on the fuel heater as described above. Be mindful even the TINIEST hole in a wire can short it out if it rubs against metal.

When testing fuel heater and fuel pump make sure the vehicle is running.
Matter of fact, run the vehicle and jiggle the wiring on the fuel pump and fuel heater, if the engine cuts off you found the issue.
__________________
1998 Ford Escort ZX2 5 speed - 279,000 miles My Daily

1992 Mercedes 300D 2.5 202,000 - Pure junk
2000 Mercedes E320 Black - 136,000 miles - Needs repair

Don't forget to grease the screw and threads on the spring compressor.
Reply With Quote
  #9  
Old 03-08-2019, 09:55 AM
nyko46's Avatar
Registered User
 
Join Date: Jan 2004
Location: Rowlett - Texas - USA
Posts: 497
Fuse Blowing Problem Solved:
Regarding the fuel pump fuse blowing I finally got the problem solved.
After reading all different suggestion about the problem, since it seems to be and electrical issue, I decided to go to the fuel heater first. Since the same fuse for the pump share power to the heater I thought it make sense to go to the heater and see how it looks like.
Just after getting the fuel bow opened I saw the heater element broken and making contact with the ground and consequently causing short to ground and automatically blowing the 30A fuse.
As soon I had the element replaced I got the truck running properly and no more blowing fuse.
It was my first time working in a Ford F250 Turbo 7.3 Diesel.
In reality this is my son in law truck. After getting the truck back in busyness we celebrate, with a help of this forum, one more lesson in how to fix this issue in his kind of car.
Thanks every one.

__________________
Nyck - TX - USA
Reply With Quote
Reply

Bookmarks

Thread Tools
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 On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -4. The time now is 08:13 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2024 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page