How to: How To: Change A Fuel Pump Relay-91-94X

[Tbars4]

..I would assume someone disconnected them from their storage location at one time (which is under the power distribution box) and didn't install them back in their rightful place..

..The problem with them "laying around" in that location is that they will collect dirt and moisture while laying on their side or upside down..This will lead to shorts and failures of these relays..

 

[patrick.sellers]

help

ok, here is the story.
i have a 92 ford explorer that i just replaced the heads on, it is all back together nice and pretty... except for the fact that i have no spark and no fuel. i have been reading all night and farting around under the hood with no luck. also the check engine light does not come on when you turn the key to the on position.
i have read through alot of the threds that you have posted and you seem pretty damn close to an expert on this. i am hoping you can put an end to all my frustations.

 

[jd4242]

ok, here is the story.
i have a 92 ford explorer that i just replaced the heads on, it is all back together nice and pretty... except for the fact that i have no spark and no fuel. i have been reading all night and farting around under the hood with no luck. also the check engine light does not come on when you turn the key to the on position.
i have read through alot of the threds that you have posted and you seem pretty damn close to an expert on this. i am hoping you can put an end to all my frustations.

Check the inertia switch in the front passenger floor board.

 

[SPSmith]

ok, here is the story.
i have a 92 ford explorer that i just replaced the heads on, it is all back together nice and pretty... except for the fact that i have no spark and no fuel. i have been reading all night and farting around under the hood with no luck. also the check engine light does not come on when you turn the key to the on position.
i have read through alot of the threds that you have posted and you seem pretty damn close to an expert on this. i am hoping you can put an end to all my frustations.

After the inertial switch I'd go for the ECM relay which controls power to most everything. I replaced that and the fuel pump relay and finally had spark and fuel. Unfortunately, I think my particular issue now is the computer.

 

[SPSmith]

..I would assume someone disconnected them from their storage location at one time (which is under the power distribution box) and didn't install them back in their rightful place..

..The problem with them "laying around" in that location is that they will collect dirt and moisture while laying on their side or upside down..This will lead to shorts and failures of these relays..

Interestingly enough, there is no provision for the relays to be attached to the bottom of the power distribution box nor any sign that there ever was. Bearing in mind that this is a 1991 model, my local Ford dealership's expert on first gen Explorers stated that this is not uncommon and to simply seal the relays up with tape. And you are correct about causing failures. When I disconnected the ECM relay I found a 1/16th inch diameter hole in one corner and there was visible rust inside.

 

[Tbars4]

..The provisions to hold those relays in place are there and have been on other Ford vehicles (F series) since the 80's..

..I do not see a reason nor have I run across another 91 X (either pre or post 5/91) that had this missing..

..Can you post pics of this item?

 

[mr cribb]

I picked up a 91 4x4 last week, build date 04/91. Looking at my pictures there appears to be a box underneath the PDB. I searched for this thread to see if the beast will awaken from the 5 year sleep it has been in.

I read on here that relays and ECM could cause no fuel delivery. Just checking all angles before it is fuel pump time.

Pics:

 

[mr cribb]

It wasn't a box underneath the PDB, it is a relay holder. They clip up into place. Swapping FP relays didn't change anything, in fact the relay from the 91 works well in my 92.

I'm not hearing the fuel pump prime/ pressurize when I flip the key on. The only thing I haven't done is swap ECM from truck to truck.

 

[Maniak]

It wasn't a box underneath the PDB, it is a relay holder. They clip up into place. Swapping FP relays didn't change anything, in fact the relay from the 91 works well in my 92.

I'm not hearing the fuel pump prime/ pressurize when I flip the key on. The only thing I haven't done is swap ECM from truck to truck.

Check the inertia switch. It was in an accident AND moved with a loader. It if took a big enough hit the switch and kick.

Its on the firewall on the passenger side, right by the trans hump. Reach your finger into the top of it and push it down.. If it moves down, it was tripped.

~Mark

 

[mr cribb]

I checked that first thing. It didn't move. This was after it being moved. After the accident the previous owner did reset the inertia switch and it started for him then. That was 5 years ago.

 

[Tbars4]

.A common issue with the inertia switch is it may not be carrying the full voltage from one side to the other..I would check that first..

..If you are still having issues then, I would click on the last link in the first post as it has every test there is for your fuel system..

 

[iteotwawki]

I think this issue is contagious.

...Is Your truck possesed???...Do you hear a whir noise after you shut your truck off and pull the keys???...Do you come out to your truck after it sits for 2-3 days and it is completely dead???...:scratch:

...You may be in need of this fix....there are several other items that may cause these symptoms, but this seems to be a common one in which my X was also inflicted with...this is a simple fix but after researching it and reading diagrahm's, i had trouble locating the hidden relay...I had changed one of these on one of my old F250's and luckily remembered where the relay location was...

WARNING as usual, this is what i did to fix my problem...attempt do do this at your own risk...

Hey TBars, my truck's got the same condition. I walk outside and the dang fuel pump cycles and I'm not even in the vehicle. Oh and it likes to cycle after I shut off the engine. Can you kindly tell me what your resolution was?

 

[Tbars4]

...:shifty_ey ..a new relay fixed it...

 

[iteotwawki]

...:shifty_ey ..a new relay fixed it...

Thanks, I'll give it a look.

 

[Razorwindmo]

...Is Your truck possesed???...Do you hear a whir noise after you shut your truck off and pull the keys???...Do you come out to your truck after it sits for 2-3 days and it is completely dead???...:scratch:

...You may be in need of this fix....there are several other items that may cause these symptoms, but this seems to be a common one in which my X was also inflicted with...this is a simple fix but after researching it and reading diagrahm's, i had trouble locating the hidden relay...I had changed one of these on one of my old F250's and luckily remembered where the relay location was...

WARNING as usual, this is what i did to fix my problem...attempt do do this at your own risk...

First and foremost, disconnect your positive and negative cables before attempting to work on anything electrical on your vehicle...

NOTE....if your first gen has the relays inside the power distribution box, don't look underneath for a relay...
...This is also similar to do on Second gen X's except the power distribution box sits in the engine bay in front of the driver and the relay itself is easily located inside with the fuses...

...This is your power distribution box, located on your passenger fender...

...If you open it up you will find large relay fuses...

...If you look under the cover, you will see where it says "Fuel Relay", this is only the fuse for the fuel relay...mine is the one in the rear of the box...(left side of this cover)

...If you look under the box you will see a set of 3 plug-ins...these are actually plugged into your realays

...on mine, I had to remove the plug in the back, directly under my fuel pump relay fuse...

..If you look close you will see a sliver of metal in which this relay is attached...you will need a flathead screwdriver to pry it to the outside with one hand, as you use your other hand to pull it loose...(i actually had to unscrew my power distribution box from the fender so i could have access to work)

...after it was removed i noticed it was a ford part and this is what it looks like...i found the replacement relay ranging in prices from 12-45 dollars

HINTS
motorcraft replacement relay seems to be the choice for replacement as they last

If you take your relay in, they will read the number off of it to cross reference it with the new one...below are the prices that matched up with my originally numbered Ford relay of -F19B9345A2A, autozone did not even try to cross reference...
Autozone-11.99 = 3 mo. warranty (most people have these go out in a couple months)
Kragen/shuck's/checker - 21.99 = 1yr. warranty (niehoff PN# RY71)
Pepboy's-24.99 = 1 yr. warranty (borg/warner PN-R647 = the one I bought)

...I hope this will be useful to those who have the same problem...Good Luck on your project...
_________________________________________________________________________________

...For info on other "No Start" conditions...

...This thread may help diagnose your no start problem if it's electrical..
Diagnosing A No Start/Slow Start - Starter Concerns

...If it's fuel related, there are several test to be found in this thread...
Fuel Pressure- Low key off, okay at idle

I have a 1991 F-150 XLT Lariat with the 5.8L and my relay is only 4 pins with a bump out. It is no longer in stock anywhere new. It is an obsolete item.