99 F150 fuel pump suddenly quit. - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars
Ford Forum Ford Forum

» Auto Insurance
» Featured Product
ยป Wheel & Tire Center

Go Back   Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars > Ford Trucks | Utes | Vans |SUVs | Crossovers > Ford F-100 | Ford F-150 | Ford F-250 | Ford F-350 | Ford Super Duty | Ford Diesel
Register Home Forum Active Topics Photo Gallery Auto Loans Garage Mark Forums Read Auto Escrow

Ford F-100 | Ford F-150 | Ford F-250 | Ford F-350 | Ford Super Duty | Ford Diesel Forum for discussion of the Ford F100, F150, F250, F350, Superduty and Diesel trucks.

FordForums.com is the premier Ford Forum on the internet. Registered Users do not see the above ads.
Reply
 
LinkBack Thread Tools Display Modes
Old 01-22-2014, 14:32   #1 (permalink)
Registered User
 
Join Date: Jan 2014
Posts: 3
99 F150 fuel pump suddenly quit.

at first I thought it was a bad pump because I had power on the pink/blk wire leading to the pump during cranking so I moved the bed (by myself!!). long story short, I cut the wires on the connector side of the pump harness and ran power and ground to pink/blk and blk respective. the pump runs and fuel gets up to the fuel rail at the engine. I don't really know how to troubleshoot between the fuel cutoff switch, relay and anything else.

I used to be an auto electrician, had my own shop for 8 years and never got stymied by electrical issues but this one has me stuck due to lack of info on the system. glad i didn't order by internet a motorcraft pump for $250 which locally cost around $377...

without the proper diagrams I'm in the dark. any help? I have found a partial diagram of the fuel pump wiring but it's not complete.

BTW, this truck has been sitting in my driveway for over 16 months with just an ocassional startup or short drive. it started within the last two weeks, but I didn't even put it in gear. just shut it off. my first thought was bad gas, but last time i filled up to 1/4 tank in late summer I added stabil and besides, i've got no fuel at the fuel rail unless i run wires from battery and ground like i said above.

complicating things is truck is parked so that I can't open passenger door to remove trim over cutoff switch. ive nearly broken the trim bending it backwards so that i can see the switch. the bed is in a precarious position so that i can get to the pump wiring on top of the tank so i don't want to simply run my "cheater" wires to the pump and move the truck at all until I've properly diagnosed the issue.

thank you for any help!! (I miss my Mitchell manuals!! LOL!

1999 F150 4.6 V8 rear wheel drive ext cab std bed.
dave1812dave is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 01-23-2014, 10:16   #2 (permalink)
Registered User
 
Join Date: Jan 2014
Posts: 3
Re: 99 F150 fuel pump suddenly quit.

two more things (still waiting to find a wiring diagram!!!!!)

the "theft" lamp in cluster lights up sometimes when cranking. (can't remember if that is normal or indicates the source of my issue with lack of power to fuel pump possibly related to anti-theft stuff) I just read up on PATS and that's normal...

Number 20 fuse (5A) in under-dash fuse panel has no power. owners guide states it is for audio, GEM and PCM modules. however, the radio/tape unit works without that fuse having power. w/o diagram I need to know where it gets power.

also, I swapped diodes in the under-hood fuse/relay panel, between the PCM and A/C clutch circuits. still no power to fuel pump.

If this isn't the best forum to be posting these technical questions, will someone PLEASE let me know where I can get in-depth info into the fuel pump system THEORY OF OPERATION as I'm still flying prettty blind.

oh, and I borrowed a scan tool. no fault codes are stored.

Looks like I hadn't mentioned THE ENGINE RUNS IF I SPRAY B12 INTO THE INTAKE, SO NO ISSUES WITH IGNITION.
dave1812dave is offline   Reply With Quote
Old 01-23-2014, 10:33   #3 (permalink)
Moderators
 
r-clar's Avatar
 
Join Date: Feb 2013
Location: Demotte Indiana
Posts: 938
Re: 99 F150 fuel pump suddenly quit.

Well first thing I will suggest is try and get it moved so you can check power at inertia switch. From what I remember it goe from fuse to switch then on to pump.


Sent from AutoGuide.com App
r-clar is offline   Reply With Quote
Old 01-23-2014, 11:25   #4 (permalink)
Registered User
 
Join Date: Aug 2011
Posts: 165
Re: 99 F150 fuel pump suddenly quit.

First thing is to get the truck in a position you can work on it.
The fuel pump fuse will not be under the dash but in the engine bay box.
Here is how the fuel circuit works:
Key to run before cranking turns the fuel pump on for about 1 second. [a short PCM timing function]
At cranking the PCM turns the pump back on full time as long as the crank is turning. [detected by the crank sensor]
The PCM circuit operates a relay only.
The relay passes power from the fuse to the pump through the crash sensor as a 'slave action' due to the current level involved.
All you need to do is verify power at different points to determine the fault area. A look at lead color coding is very helpful.
Is it the fuse, the relay, the crash sensor or the wiring and/or bad fuel.
You already did a lot of work for near nothing to get at the fuel pump.
Step back and think a bit before acting.
Good luck.
Bluegrass is offline   Reply With Quote
Old 02-02-2014, 12:47   #5 (permalink)
Registered User
 
Join Date: Jan 2014
Posts: 3
Re: 99 F150 fuel pump suddenly quit.

Turns out my FIRST impression that the pump itself was defective, was correct. I ordered a pump online (motorcraft) for $250 instead of the awful local price of $377. Installed the pump, and the engine fired right up!!
dave1812dave is offline   Reply With Quote
Old 02-04-2014, 19:06   #6 (permalink)
Dazed and Confused
 
CatSkinner's Avatar
 
Join Date: May 2012
Location: Upstate New York
Posts: 3,571
Re: 99 F150 fuel pump suddenly quit.

Good to hear!
__________________
'Scuse me, while I scrape this Honda outta my treads.
CatSkinner is offline   Reply With Quote
Sponsored Links
Advertisement
 
Reply

  Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars > Ford Trucks | Utes | Vans |SUVs | Crossovers > Ford F-100 | Ford F-150 | Ford F-250 | Ford F-350 | Ford Super Duty | Ford Diesel



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
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 Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Powered by vBadvanced CMPS v3.2.2

All times are GMT -7. The time now is 02:42.



Powered by vBulletin® Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Content Relevant URLs by vBSEO 3.6.0
Garage Plus vBulletin Plugins by Drive Thru Online, Inc.