1988 F-250 fuel pump problem

Reply

  #1  
Old 04-11-13, 12:10 PM
2
Member
Thread Starter
Join Date: Jul 2009
Location: Cecil County, MD
Posts: 209
Received 0 Votes on 0 Posts
1988 F-250 fuel pump problem

1988 Ford F-250 5.0 EFI with AOD 3 Days ago, my truck stalled on me. I got it going, put it in gear and it stalled again but this time would not start. Checked for spark. I had spark. Checked for gas. I pulled the fuel line behind the injector rail and had no gas.
I had it towed back to a place I could work on it and started at the tank. I pulled the fuel lines from the tank and had no gas flow. I replaced the pump and screen in the tank. Didnít help. I replaced the fuel pump relay and it still didnít help.
Oh, and before I started all this I checked the inertia switch. I donít really know what it is supposed to look like normally but it seemed to me that the reset button was in the down position even though I could see red through the window. I popped the relay and pressed the button anyway. It stayed down.
My multimeter bit the dust so I have not been able to check for voltages but I wouldnít know what to check anyway. Iíd like to confirm that power is going into and out of the relay.
I went to Autozone and got a new fuel pump relay and put it in but someone suggested I replace the one next to it also. I donít know why but that is what was suggested.
OK, there you have it. Any advice? Yes, there is gas in the tank.
 
Sponsored Links
  #2  
Old 04-11-13, 03:58 PM
M
Forum Topic Moderator
Join Date: Mar 2005
Location: USA - N.E.Tn
Posts: 46,628
Received 176 Votes on 156 Posts
Does the pump hum when you first turn on the ignition? If you can hear it cut on an run a couple of seconds, you'll know you have power going to pump. If it doesn't cut on, I'd trace the wires and see why.

You can get a cheap analog multi meter for $10-$12. They are easy to use. I've never been able to master the digital ones
 
  #3  
Old 04-11-13, 06:39 PM
2
Member
Thread Starter
Join Date: Jul 2009
Location: Cecil County, MD
Posts: 209
Received 0 Votes on 0 Posts
I was out there tonite working on it. Here's where it stands. I have power at the relay where there is supposed to be power. Yellow wire-hot all the time. Red wire -hot when key is on.
I grounded the fuel pump connector on the OBD terminal, switched the ignition on and heard the relay initialize. I traced the wire to the inertia switch and found I had power to the switch but not coming out. I cut the thing off and spliced the wires(I promise I will put it back on).
Understand, I am almost deaf so listening for the in tank pump to prime while I am standing 100 feet from the interstate is pretty much an exercise in futility. What I ended up doing was pulling the fuel lines and after I turned the ignition switch on I checked to see if any fuel had spurted out of the tank.Of course none had.
The schematics I found showed the wire from the inertia switch going to the main fuel pump. This wire split and went to the tank selector which provided power to the appropriate in tank fuel pump.
I only have one tank. The truck has never had two tanks. So where is the in tank fuel pump getting its power. From the main fuel pump?
 
  #4  
Old 04-12-13, 05:54 PM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: United States
Posts: 10,352
Received 45 Votes on 36 Posts
The schematics I found showed the wire from the inertia switch going to the main fuel pump. This wire split and went to the tank selector which provided power to the appropriate in tank fuel pump.
I only have one tank. The truck has never had two tanks. So where is the in tank fuel pump getting its power. From the main fuel pump?
That is a strange one. The 1988 Ford I had was an F-150 with two tanks and three fuel pumps, I thought the 250 would have been the same. Have you checked a service manual yet?
 
  #5  
Old 04-13-13, 01:36 PM
2
Member
Thread Starter
Join Date: Jul 2009
Location: Cecil County, MD
Posts: 209
Received 0 Votes on 0 Posts
That makes sense an F-150 with dual tanks would have three pumps. Two in-tanks and a high pressure. This F-250 was ordered with a utility body on it.
Today I went down and worked on it. I don't know how I can check for voltage at the in-tank pump. When you turn the key on, the in-tank pump does a one second prime and shuts off.
Currently, I don't have an inertia switch on the system. I cut it off and spliced the wires yesterday. So, I put a test light on the splice and turned the key. The light came on for one second and shut off, just as it is supposed to do.
Before I did that test, I pulled the connection at the tank, looked at it and cussed a little and put it back on. I tested output at the relay and it all seemed fine. After the test at the splice, I tried to start the truck and it fired right up.
I shut it down and tried again and it fired up. I let it run for maybe a minute and it quit running.
It didn't stall a bit, sputter or miss and quit. It just quit real sudden like and I haven't gotten it started since.
At this point, after I confirm I still have spark, I guess I am going to the auto parts store and getting a couple of spools of wire and some connectors and I am going to start bypassing everything.
Anybody have any ideas?
 
Reply

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 Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description: