Crazy Fuel Pump

[firemarshalmike]

Hello,
Back again!! Not a PATS issue. I have a 1999 Ford Explorer Sport, 2dr, 2wd, 4.0L V6, SOHC. The VIN starts with a “1” and the engine code on the VIN is “E”. I am having a starting problem. Engine will rotate but will not start. When I turn the ignition to the run position, (just to the point where the gauges turn on), the fuel pump will not turn on, then again, sometimes it will. Rocking the ignition switch on and off will sometimes get the fuel pump to engage. Once I hear the “fuel pump sound”, the vehicle starts right up and runs great. Jumping the vehicle has gotten the fuel pump to turn on. I have checked, swapped and replaced the fuel relay, PCM relay. I can find no breaks in the wiring that I can get to. This same problem happened over a year ago and I replaced the PCM relay and the problem stopped. Now it is back and new relays have not helped. If a fuel pump is going bad, would that not mean that the engine would not start, or if it did start it would cause idling and stalling problems while driving? This car runs great once the fuel pump does turn on. No stalling, idling problems at all. The fuel pump seems like it needs a jolt of electricity to get going. I would like to get into the wiring on the inside of the power distribution box under the hood. Does anyone know how to open the box? This is strictly electrical I believe. Any help would be appreciated.

 

[deweyville65]

If "rocking" the ignition switch back and forth causes the fuel pump to turn on, then I think I would be looking at the ignition switch for starters. If a visual examination shows good, then try jumping the fuel pump relay with battery voltage. When my fuel pump went bad, I could rap the bottom of the fuel tank with a soft faced mallet, and the pump would start running, until I shut it off. when I replaced the pump, I disassembled the old one and found a bad spot on the armature.

 

[firemarshalmike]

Thanks

Thanks for replying. By ignition switch, do you mean the switch located behind the lower panel of the steering column or the actual tumbler that the key goes in? Also, if I turn the key on, the PCM clicks, the fuel relay clicks, no fuel pump activation, (2 out of 10 tries), and I pull the fuel relay out, when I put it back in, should it try to activate the pump again? This being done with the key in the on position? I know if I pull the PCM relay, while the key is on, and put it back it activates itself and the fuel pump relay without me turning the key off and on again. Does that make sense? I really appreciate your input. I have gone and got a rubber mallet to try your trick. I have been under the car, the key is on, PCM relay clicked, fuel relay clicked, and tapping the fuel tank has not gotten any fuel pump activation.

 

[deweyville65]

The actual ignition switch, bottom of steering column. Sounds though, like the switch is working. Rapping the tank worked for a while, but then the pump died completely. You might go under the truck and locate the wiring connector along the left side frame rail, check the fuel pump wire for voltage. Remember the pump has battery voltage when you first turn the key, drops to about 6V until the engine starts, then goes to battery voltage. Believe me, this drove me nuts until I read about this on this forum.

 

[1996BLKBauer]

Check your inertia switch, mine was slightly unplugged, and I had the same problem. sometimes it would work sometimes it would not. it is located in the passenger footwell on the firewall.

 

[firemarshalmike]

Going to replce the fuel pump. Inertia switch is good. Tapped on the tank a second round, fuel pump came on. Should I replace the pump alone or should I replace the entire assembly, fuel sending, unit, etc. The gas gauge works great. It has the stock fuel pump in it now. I just don't have $350-400 for a motorcraft assembly nor do I know if the wiring will be the same on an aftermarket pump and/or assembly. Thank you

 

[RomeovilleIL]

Buying a complete assembly is really not needed. Aside from the pump itself and the fuel guage sending unit, there just isn't anything else there besides the fuel lines. Once you have it out of the truck you'll see there isn't much to replacing the pump. Two hose clamps, the wire connector, and the retaining strap. Be sure to use a new strainer sock and replace the flexible hose & clamps (usually comes with the kits).
This job is only difficult due to accessing the pump assembly in the tank. The relacement of the pump itself is very easy.

BTW - those pumps are a heck of a lot cheaper online! Price out the Airtex at any parts house will be around $100 without the sock. Online retailers have them all day long under $45 delivered with the sock. I have installed the Herko as well with no problems reported after 2 years (about $20 on Ebay). Just get the correct pump number for your engine ie 2158, 2068, 2157 etc. to match the pressure rating and connector.

 

[unclemeat]

My mechanic says that Carter is the OEM manufacturer. Rock Auto has them for about $100.

 

[firemarshalmike]

Thank you for your help. I ran into the situation of part 2157 and 2158 AC delco brand saying they both fit. I have a 1999 Ford Explorer Sport 2wd 4.0L SOHC Engine type E on the VIN and "1" as first digit on VIN. A lot of folks selling pumps list "ALL" Ford Explorers within a certain model year, others are more descriptive such as 2 or 4 door. Any thoughts?

 

[RomeovilleIL]

For the 1999 4.0 SOHC catalog lists a lot of choices. The pressure parameters are the same, the difference is the electrical connection. The truck *should have* the thin 2 blade connector which is the hook up on the Airtex E2471. Confusion sets in because you *might have* the wide 2 blade wire connector in the tank which is the connection on the Airtex E2068 (normally associated with vin 3). The E2471 is a safe choice to buy without first disassembling the truck and verifying the connector since it normally comes with a harness adapter to allow both connector types without splicing.

I believe both of the AC Delco parts you listed are universals that should have correct flow and physical dimensions that work ok but require a simple wire splice for installation if you happen to have the wrong plug type.

2471
http://www.rockauto.com/catalog/moreinfo.php?pk=1347118&cc=1354542

 

[firemarshalmike]

Thank you for the guidance. I have the pump on order.

 

[firemarshalmike]

Replaced Fuel Pump (Still have same problem)

Hello all and Happy Thanksgiving!

I replaced the fuel pump and thought I was set. Still having the same problem. Have to rock the key cylinder back and forth to get the fuel pump to engage.
PCM will click but the fuel relay will click once only or not at all when the fuel pump will not engage. When the fuel pump works it goes through the following sequence: the fuel pump relay will click 2 times, fuel pump starts, then the fuel pump relay clicks once more when the fuel pump is primed. I have replaced and swapped these relays. Do you think it is a problem at the key cylinder? Air bag light is staying on and is blinking a 3 and 6 series flash. Any connection?

 

[99SportX]

My sport has been doing this exact same thing. It did it on and off ever since I fired it up this spring after sitting all winter. I would just cycle the ignition switch and it would be fine. Never got stranded... Then I went to start it a few days ago and nothing. No amount of cycling the ignition would fix it. I then swapped the fuel pump relay with the horn relay. Still nothing. Then a few days later I swapped the pcm relay with the blower motor relay. It primed! I thought I was out of the woods until the next day it didn't prime once again.

I can feel the fuel pump relay click on and then off after a few seconds, so that implies that the pcm signal is functional. I am betting on my pump but I sure hope you find it is something else that is far easier to fix since I have a full tank!

 

[firemarshalmike]

Electrical

I wish I knew. Out of 10 tries (key on only) the pump works 8 times. If it was my car and not my 17 year old daughter's, I would just live with it. I have bought new PCM relays, fuel pump relay, swapped the relays, checked the PCM diode, all fuses, inertia switch, and wiring. Check out the access panels members on this forum have cut above the tank. One is done on a 1999 Ford Explorer Sport. I guess I am going to wait on a total failure of whatever the problem is.

 

[budwich]

you could replace your ignition switch OR you could use a meter to watch for voltage going thru the relay towards the pump OR as you suggest, just wait til you are totally "broken down" and then hope you have the parts at hand to get you going again.

 

[99SportX]

When you turn the key on but don't crank, the pcm relay will activate, just after, the fuel pump relay will click on and then a few seconds later, click off. Does the fuel pump relay click on and off 10 out of 10 times?

If the relay has been replaced and is functioning normal and the inertia switch verified, and the fuel pump replaced, then the only thing left is wiring, possibly corrosion at one of the connection points along the way.

 

[BEARDSLEY]

Hello,
Back again!! Not a PATS issue. I have a 1999 Ford Explorer Sport, 2dr, 2wd, 4.0L V6, SOHC. The VIN starts with a “1” and the engine code on the VIN is “E”. I am having a starting problem. Engine will rotate but will not start. When I turn the ignition to the run position, (just to the point where the gauges turn on), the fuel pump will not turn on, then again, sometimes it will. Rocking the ignition switch on and off will sometimes get the fuel pump to engage. Once I hear the “fuel pump sound”, the vehicle starts right up and runs great. Jumping the vehicle has gotten the fuel pump to turn on. I have checked, swapped and replaced the fuel relay, PCM relay. I can find no breaks in the wiring that I can get to. This same problem happened over a year ago and I replaced the PCM relay and the problem stopped. Now it is back and new relays have not helped. If a fuel pump is going bad, would that not mean that the engine would not start, or if it did start it would cause idling and stalling problems while driving? This car runs great once the fuel pump does turn on. No stalling, idling problems at all. The fuel pump seems like it needs a jolt of electricity to get going. I would like to get into the wiring on the inside of the power distribution box under the hood. Does anyone know how to open the box? This is strictly electrical I believe. Any help would be appreciated.

Obviously this post is from way back when, but I am experiencing the same exact issues and was curious if you ever diagnosed the problem. THANKS!

 

[koda2000]

Bad fuel pump.

 

[BEARDSLEY]

Thanks koda, was this your original post? I was hoping mine wasn't the fuel pump because I've never had any idling issues or stalls while driving. The other day it wouldn't start, the fuel pump wouldn't engage with the key on at all. I switched the relays around and wiggles the fuse box. Then 6 out of 10 times the due pump would engage. Was thinking maybe some frayed wires or something electrical. Similar to this original post. Thoughts? Thanks.

 

[koda2000]

Thanks koda, was this your original post? I was hoping mine wasn't the fuel pump because I've never had any idling issues or stalls while driving. The other day it wouldn't start, the fuel pump wouldn't engage with the key on at all. I switched the relays around and wiggles the fuse box. Then 6 out of 10 times the due pump would engage. Was thinking maybe some frayed wires or something electrical. Similar to this original post.
Thoughts? Thanks.

In my experience with Ford fuel pumps (which is not insignificant) this is what fuel pumps do when they are worn out. Usually begins when the weather turns cold.