Fuel Pump Relay Issues

[dwpenney01]

We have a 1991 EB Explorer with 187K miles. Today my wife had problems starting it. Usually we turn the key to the On position and let the Fuel pump prime before starting. Now when she did it, it would not prime. I thought the Fuel pump had gone out. But after a few more tries, the pump primed and started.

Not knowing how the Fuel pump is powered, I need to find out if this is a Relay problem or is the Fuel pump going bad. The fuel pump on my truck (F-150) on the front tank went and it just quit. With the Fuel Pump sometimes working and sometimes not working I am wondering if it a Relay problem.

Anyone seen this problem?

Thanks,

Donnie Penney
donnie@penneyscompter.com

 

[TPLYNCH]

Did you hear the FP whining when it was turned to ON when it wouldn't start? If not, then start w/the relay. It's in the black box under the hood, near the firewall I think. If it happens again and you don't hear the whine, leave the key ON, pop the hood, open the box and jiggle the relay. If you hear the FP start to whine, then you've found your problem... and hopefully it is this simple cheap problem!

 

[mrboyle]

It could be either the pump or the relay. The relay is far cheaper than the pump, but is the savings worth the risk of being stranded? If it were mine, I'd replace both the pump and the relay. I also recomend stepping up and buying a Ford pump instead of an aftermarket. I have seen far fewer problems with the Ford pumps than the unreliable aftermarket pumps.

 

[Glacier991]

About a year ago I had a situation where I could not start my Ex. I was at work and had my gf come get me. Just to show her, I got in (after she drove 20 minutes to get me) and bang, it started right up. Go figure. Ran fine for about 3 months when it happened again. This time it wouldn't start and I had it towed home. I stole power from the cigarette lighter and fed the puel pump circuit power to the fuel pump at the interial switch (under the passenger side dash), still nothing. Ultimately it turned out to be the fuel pump. Not a fun replacement, but not terribly difficult.
Good luck.


Happy exploring

Chris

 

[zavetsky]

Same problem!!!!

I just got home after having the SAME EXACT problem about an hour ago, so its fresh as hell in my head....(yeeha)...

FOr the last few months, the truck would occasionally not strat after being run for about 15 minutes and then being turned off, and then trying to restart another 10 minutes or so later (like when I go to pick up kids at school!)........
I get no relays clicking or fuel pump sounds at all...normally I get all kinds of loud buzzes, clicks and whirs....

Usually, if I sit a few minutes, I can turn the key and get all the noises back and it starts right up.......

Today however, no such luck....sat for a good 45 minutes and no luck..

Tried tripping the fuel shutoff switch and reset it, no help....

Then I pulled out my handy dandy code scanner....Set it up accordingly and did the test.....NO CODES!!! Dead as a doornail...scanner is fine...battery for it is fine...

So, after scratching my head for a few minutes (and like 30 people stopping me to say "Are you ok??", I finally figured to try disconnecting the negative terminal to the battery....

As I reconnected it after having it off a few minutes, I saw the code scanner jump to life!!!!!! ANd then the scanner started spitting initializing codes....

I turned off the scanner and tried the key...started first try!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

I think my problem could be a bad or going-bad engine control computer....could it be anything else???

DZ

 

[travish_1]

I had this same problem on my 94 X. I couldn't figure it out but finally a shop tried switching the AC relay switch with the fuel pump relay switch, it started right up. Picked up a relay switch from autozone for about 16 bucks.

 

[duck210]

I have had problems with both the starter, and fuel pump relay. I was stranded at work for about an hour one night. The fuel pump would not prime. Finally after jiggling the relay as I had done prior to this episode it started. I had no problems for weeks. Then one day....guess what? It happens again, but this time it was the new relay. Being somewhat of a junk collector I reached for the old relay that I stored in the console. I replaced the new with the old, she fired like it aint nobodys business. I concluded that maybe the connectios were oxidized. Went back to the dealer and bought a tube of (write this down) "silicone brake caliper grease AND dielectric compound. XG-3." The parts guy told me I might think about the expense. It afterall is $10.00 a 3oz tuble.
BIG DEAL! This stuff did the trick. I lightly greased every contact in the under the hood fusebox.

I have had ZERO problem with any relay since. In fact a guy I work with had the same thing happen with his explorer (same year). I saw him goofing under the hood with the same difficulty as I experienced. He asked me for a jump start. I took the grease out of the console. His rig fired up, he drove away happy, and has no problems since. Boy was I a hero that day. If only he knew the hell I paid to have the knowlege to fix his problem!

 

[zavetsky]

???/

Was your truck (and his for that matter) turning over??

Mine was....

In my case, I think the lack of any codes at all from the scanner indicates something other than a fuel pump relay....

But I may try that silicone grease trick.

DZ

 

[jimbo74]

one day after work i tried to start my truck... not a darn thing happened... i threw in a new relay, still nothing... no fp whine present at any time....... eventually, i figured out that i accidentally triped the inertia switch... so i reset it, and it started up without a problem... according to the ford manual, a pothole can set off the inertia switch!!!!

 

[zavetsky]

I tried that...in fact, I purposely tripped mine to test it.....whacked it sveral times with a screwdriver and it tripped....

Reset it and nothing.....

I'm telling you.....the next time this happens to anyone, plug in your scanner and check for codes...mine was dead as a doornail...

A bad fuel replay isnt gonna do that I wouldnt think........

It would show up as a bad code, but the computer would not shut down......

 

[Glacier991]

Have to say that no power to the scanner more sounds like you had a bad battery connection, and fixed it (for now) by removing and replacing the cable? No power at the scanner connection ain't a fuel pump or relay problem.

My 2 cents anyway


Happy Exploring

Chris

 

[duck210]

Hi Zavetsky,

When I had the starter relay problem, the motor would turn over. When it's nice and quiet outside keep your door open and turn your key on. You should hear the fuel pump prime for a second. Not saying the dielectic grease is a cure all, but it sure is a cheap and easy fix.
When I was having problems starting my engine it became routine to go wiggle the relay until it would start. I have had no problems in a year now.

 

[sailorman101]

another problem i had on my previous 91 explorer xlt was the wiring harness that runs down the left valve cover. when i got it back from the body shop after having some collision damage repaired they failed to secure it in place and it was sitting on the exhaust manifold where it burned into it just enough to ground out. this not only created a problem of not starting but played havac with the shift computor and messed up the lockout and shift points. i had two dealerships and two independant transmission shops tell me i needed a new trany and finally found the problem when it failed to start and i was troubleshooting that problem

 

[zavetsky]

I agree that this is one way to test.....I had just that problem.....no fuel pump priming...but I also didnt get any of the other under hood relays and stuff clicking.....

I will probably grease all of them just to be safe, but one fuel pump relay probably isnt going to prevent the whole ECM from spitting codes.......I think I will test this theory though.....If I pull the relay altogether and test for codes, my guess is that I will still get codes....Only one way to find out though!!!

...now, if only the rain would stop....
DZ

Originally posted by duck210
Hi Zavetsky,

When I had the starter relay problem, the motor would turn over. When it's nice and quiet outside keep your door open and turn your key on. You should hear the fuel pump prime for a second. Not saying the dielectic grease is a cure all, but it sure is a cheap and easy fix.
When I was having problems starting my engine it became routine to go wiggle the relay until it would start. I have had no problems in a year now.

 

[jDan]

I have had similar problems w/ my 92. It would not start when it was cold, expecially during the winter months. It would take four or five tries to get it started. It would turn over but wouldn't fire. The problem went away as it started to warm up, but a couple mornings ago it reared it's ugly head again. Has anyone had anything similar?