Fuel pump problem

In_the_works

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I've been having some problems getting my truck to start lately (over the past 2 weeks). I knew that my battery was about due, so I bought an Optima to replace it, and that solved the problem for a few days, but then about a week ago it started giving me the same problem. Now the only way I can get it to start is by giving it a jump from a running vehicle. I ended up taking it to a mechanic today to get a diagnostic done, ($80 bucks, thank you very much), and all he was able to tell me was that no current was getting to the fuel pump. Has anyone had a problem similar to this on their ford? Any suggestions?

BTW the engine is an efi 5.8l
 

Gabe Lara

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You may want to check out your alternator and the voltage regulator on it as well.
It may not be charging your batt. as it should, resulting in the drop, and lack of proper current to the fuel pump.

-Gabe
 

tkr

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Just to make sure I understand, you turn the key and engine cranks over but won't start. So you hook up the jumper cables to another vehicle and it starts?? Was the mechanic you took it to able to duplicate the problem??
 

In_the_works

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Correct, it will crank, but not fire up. The mechanic said that he was not able to get it to run even after jumping, but I haven't had a problem with that yet, so I'll have to see if I can even get it out of the shop when I go to pick it up today. And the alternator was tested and was working fine.
 

empire231

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same type of problem happened on my dads old school BENZ. we solved the problem by running a new wire straight to the fuel pump and it worked fine after that. it's a quick fix, but I'm sure there's another way to do it. we thought the pump was bad but that proved us wrong.
 

tkr

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If you're not able to test the circuit yourself, the first thing I'd recommend is to replace the fuel pump relay. Possibly the contacts are dirty. Otherwise, assuming the mechanic is correct, its just a matter of tracing the circuit to find out where you're losing power.
 

matt_helton

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i think your mechanic is high on ludes. how in the heck could it be a fuel pump or pump circuit problem if it fires up when its jumped(same as having a good batt in the truck). if you have a no crank situation you need to see whats killing the battery, check for a constant draw or a faulty charging system, bad cable, connection, ground or just a bad cell in the battery. but if you still think its a fuel pump problem, an easy way to rule it out is to turn the key on and hit the pressure test port on the fuel rail with a screw driver and see if gas squirts out, or just go back to the harness at the tank and check for power. but i dont understand how it needing to jump start could be related to a fuel pump problem, unless we arent getting all the info in the first place.
 

hxckidd

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my ex had that problem on her 94 ranger and it was the fuel pump relay. if you tapped on it then tryed starting it, it would turn over fine but the other times it would crank and want to start but just die. It was a pretty cheap part too. you might look into that.
 

John Bitting

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I had a similar problem with my bronco. I ended up replacing that coil thing that is mounted on the inner fender well, it was like $12. It is what the battery positive runs into? I am drawing a blank on the name of it? I would turn the car over and it would click and then turn it over and it would start fine.
 

singlehanded

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My starter solenoid went out on my f-150 a few months ago but it wouldnt crank or couldnt be jumped it did absolutly nothing when I turned the key??? sounds like something different. Maybe a bad wire connected and for that much cash they should have been able to tell you what it needs to fix it not just that it isnt getting voltage. I go to wilsons on saturn in placentia/ or maybe its brea by imperial and kramer they are probably the best shop around.
 

Travisfab

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My Bronco (and my dads) had a similar problem, if the truck will start when being jumped and stay running it is defiantely not the fuel pump or relay. Kragen will test the starter, alternator, battery for free
 

ntsqd

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Never say 'definately' until you have actually ruled out the possibility. Modern stuff is much more voltage sensitive than older vehicles. If the pump relay isn't getting enough volts or current it will not work.
I'd try a new relay to see if that does the trick.
 

In_the_works

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Where is the fuel pump relay located on F150s? I just spent about an hour going through my engine compartment making sure all my grounds were appropriately contacted. Something else I noticed while driving it around was a very high pitched quiet hum coming from both fuel pumps. This may have always been the case ,I just had my stereo too loud, but now I'm listening for any little noise I can. And thanks to everyone who has responded so far.
 

In_the_works

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Do you mean the Inertia switch? The one behind the pass. side kick panel? On a side note, I've been able to get it to light up the past 2 times i tried, I just hope my luck holds out...
 

tkr

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It would make a little sense as well if your fuel pump was bad. Extra current through the pump motor could make it work sometimes, but that would mean your mechanic was wrong about not getting power.
Anyway, the fuel pump relay is in the engine compartment fuse box. There should be a label on the underside of the cover to show you which relay it is. Like everone else has said, these relays fail quite often, sometimes on their own, sometimes from a fuel pump drawing too much current. If you're pump is noisy, chances are your filter is plugged and has worn out your pump.

Good Luck
 

billymanfroy

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There's a relay for key on (the 2 seconds worth of pump to pressurize the system) and then there's another one for key on + engine running (keeps the pump running if it senses spark). I've heard a lot of people have this problem with rangers and it's usually one of those relays. I won a race once cause the guy couldn't figure it out in time to make the start.

If it won't run check your fuel pressure w/ the key on and then after you start cranking it. The tapping trick usually does the job for diagnosing it also.

You could always take it to a mechanic who actually specializes in Fords also. Good luck.
 

tkr

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"There's a relay for key on (the 2 seconds worth of pump to pressurize the system) and then there's another one for key on + engine running (keeps the pump running if it senses spark)"

Actually, the PCM Power Relay is energized in start or run, and in turn sends power to both the PCM and the Fuel Pump Relay. The PCM will ground the coil in the Fuel Pump Relay for 1-2 senconds when the key is turned on, then will shut it off until it sees a crank signal(PIP). Once it does it grounds the relay again until the key is shut off. From the relay, the power goes through the inertia switch directly to the fuel pump. I've seen relays go bad, contacts and terminals melt from excessive current, and fuel pumps go bad. But to date I have yet to see a PCM Power Relay go bad or a PCM not ground the Fuel Pump Relay unless the ignition module was bad.
 
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