89 F150 - Fuel Pumps not running - unusual EEC
10-17-2010, 03:15 PM
#1
Junior Member
Thread Starter
Join Date: Oct 2010
Posts: 2
Likes: 0
Received 0 Likes
on
0 Posts
89 F150 - Fuel Pumps not running - unusual EEC
Maybe someone can give me some help since I for my 89 Lariat? I have combed the posts, trying every combination of keywords I could think of.
My F150 started and ran just fine until I didn't start it for a month. Now it will not start. No pump sound. I can hear two clicks from the FP relay (or the EEC relay?). The Inertia switch seems okay. I tested that by listening for the relay clicks (no clicks with the popup button up, clicks with it down).
I was going to check the FP by grounding pin# 6 but the EEC tester is different than any I've seen where #1 and #2 are at the top and 4,5,6 are on bottom. Mine has more connections. I don't want to take a chance on grounding the wrong pin and frying something. Where can I find a diagram of this one?
Also someone mentioned hitting the gas tanks and the external FP with a hammer.
My F150 started and ran just fine until I didn't start it for a month. Now it will not start. No pump sound. I can hear two clicks from the FP relay (or the EEC relay?). The Inertia switch seems okay. I tested that by listening for the relay clicks (no clicks with the popup button up, clicks with it down).
I was going to check the FP by grounding pin# 6 but the EEC tester is different than any I've seen where #1 and #2 are at the top and 4,5,6 are on bottom. Mine has more connections. I don't want to take a chance on grounding the wrong pin and frying something. Where can I find a diagram of this one?
Also someone mentioned hitting the gas tanks and the external FP with a hammer.
10-17-2010, 03:46 PM
#3
Senior Member
Join Date: Jul 2008
Location: Long Beach Calimexifornia
Posts: 58,557
Received 1,162 Likes
on
647 Posts
Maybe someone can give me some help since I for my 89 Lariat? I have combed the posts, trying every combination of keywords I could think of.
My F150 started and ran just fine until I didn't start it for a month. Now it will not start. No pump sound. I can hear two clicks from the FP relay (or the EEC relay?). The Inertia switch seems okay. I tested that by listening for the relay clicks (no clicks with the popup button up, clicks with it down).
I was going to check the FP by grounding pin# 6 but the EEC tester is different than any I've seen where #1 and #2 are at the top and 4,5,6 are on bottom. Mine has more connections. I don't want to take a chance on grounding the wrong pin and frying something. Where can I find a diagram of this one?
Also someone mentioned hitting the gas tanks and the external FP with a hammer.
My F150 started and ran just fine until I didn't start it for a month. Now it will not start. No pump sound. I can hear two clicks from the FP relay (or the EEC relay?). The Inertia switch seems okay. I tested that by listening for the relay clicks (no clicks with the popup button up, clicks with it down).
I was going to check the FP by grounding pin# 6 but the EEC tester is different than any I've seen where #1 and #2 are at the top and 4,5,6 are on bottom. Mine has more connections. I don't want to take a chance on grounding the wrong pin and frying something. Where can I find a diagram of this one?
Also someone mentioned hitting the gas tanks and the external FP with a hammer.
Last edited by ymeski56; 10-17-2010 at 03:49 PM.
10-17-2010, 05:34 PM
#4
April 2010 TOTM Winner
Does it spin over?
Do you have two fuel tanks?
If yes, have you tried both intake pumps to see if it will start by switching tanks?
Have you put fresh gas in since you've been trying to get it back running?
The high-pressure inline pump on the frame rail runs 100% of the time;
it shuts off after 5 seconds with a "Key on/No start" position though.
FYI- As you know the 1987-89 F150's have 3 fuel pumps with the frame mounted high-pressure pump pulling fuel from the Dual-Function Reservoir while it is being continuously refilled from one or the other low-pressure in-tank fuel pumps.
With that said, I think it is possible for one of the in-tank pumps to quit pumping fuel and the frame-mounted HP pump to continue to pull all of the fuel from the DFR until the engine dies from a lack of fuel. (It sucked it dry, there was no fuel pressure, almost no gas in my fuel filter and frame-mounted fuel pump the first time this happened, because I removed it all and installed a new filter, swapped the fuel pump with a spare I already had and almost no gas spilled out when I broke the connections, I re-installed the EEC computer and checked all fuses, put it all back together and still it would just spin and spin until I used Starting Fluid.
With the front tank full of fresh gas, all the engine would do was spin & spin and not start until I removed the air filter duct each time and sprayed Starting Fluid into the air intake while a friend turned the key to start the engine, it would start right up and then die. I continued to spray for about 20-25 seconds and then the engine continued to run on its own.
I drove my truck for over 3 months and there were no problems as long as I didn't switch to the back tank.
I think; the HP fuel pump loses prime and requires spraying Starting Fluid into the air intake to get it primed again.
I recently replaced the fuel pump in my rear fuel tank and no problems!
Hope this helps!
Do you have two fuel tanks?
If yes, have you tried both intake pumps to see if it will start by switching tanks?
Have you put fresh gas in since you've been trying to get it back running?
The high-pressure inline pump on the frame rail runs 100% of the time;
it shuts off after 5 seconds with a "Key on/No start" position though.
FYI- As you know the 1987-89 F150's have 3 fuel pumps with the frame mounted high-pressure pump pulling fuel from the Dual-Function Reservoir while it is being continuously refilled from one or the other low-pressure in-tank fuel pumps.
With that said, I think it is possible for one of the in-tank pumps to quit pumping fuel and the frame-mounted HP pump to continue to pull all of the fuel from the DFR until the engine dies from a lack of fuel. (It sucked it dry, there was no fuel pressure, almost no gas in my fuel filter and frame-mounted fuel pump the first time this happened, because I removed it all and installed a new filter, swapped the fuel pump with a spare I already had and almost no gas spilled out when I broke the connections, I re-installed the EEC computer and checked all fuses, put it all back together and still it would just spin and spin until I used Starting Fluid.
With the front tank full of fresh gas, all the engine would do was spin & spin and not start until I removed the air filter duct each time and sprayed Starting Fluid into the air intake while a friend turned the key to start the engine, it would start right up and then die. I continued to spray for about 20-25 seconds and then the engine continued to run on its own.
I drove my truck for over 3 months and there were no problems as long as I didn't switch to the back tank.
I think; the HP fuel pump loses prime and requires spraying Starting Fluid into the air intake to get it primed again.
I recently replaced the fuel pump in my rear fuel tank and no problems!
Hope this helps!
Last edited by 1987 F-150 XLT 4x4; 10-17-2010 at 08:21 PM. Reason: Added word
05-22-2011, 05:17 PM
#6
Senior Member
Bringing back an old thread but I need to figure out which wires to jumper to bypass the fuel pump relay. I'm not getting power to my pump. I turned the key back and forth about 10 times and finally got it to start, drove it home, now it wont start again. I'm thinking its the relay but I want to bypass to test.
05-22-2011, 05:41 PM
#7
Senior Member
Join Date: Jul 2008
Location: Long Beach Calimexifornia
Posts: 58,557
Received 1,162 Likes
on
647 Posts
Bringing back an old thread but I need to figure out which wires to jumper to bypass the fuel pump relay. I'm not getting power to my pump. I turned the key back and forth about 10 times and finally got it to start, drove it home, now it wont start again. I'm thinking its the relay but I want to bypass to test.
Trending Topics
05-22-2011, 06:39 PM
#8
Senior Member
The fuel pump relay only has 5 terminals. There's a fuel pump ground on the eec test plug, so I would ground that one?
I bought a replacement relay since it was cheap but it made no difference. I used a test light and I'm getting voltage at the red wire going into the relay, and the white/yellow with green stripe. Which wire off the relay goes to the pump itself? I can't find a diagram with color or terminal number labels.
I bought a replacement relay since it was cheap but it made no difference. I used a test light and I'm getting voltage at the red wire going into the relay, and the white/yellow with green stripe. Which wire off the relay goes to the pump itself? I can't find a diagram with color or terminal number labels.
05-23-2011, 08:45 AM
#10
Senior Member
Well I'm not sure exactly what I did, but its working now. I double checked all the connections, everything seemed fine. I turned the ignition on to test the eec terminal, and the fuel pump kicked on... I shut it on and off a few times with no problems. I guess there was a loose connection somewhere that I snugged up just enough. My guess is one of the wires going into the relay was loose.