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Fuel Pump not getting power


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xxmatthewxx
New User

Jan 8, 2006, 7:11 PM

Post #1 of 10 (3835 views)
Fuel Pump not getting power Sign In

My 94 plymouth voyager 3.0 died on me and quit running. I traced it to the fuel pump and dropped the gas tank changed out the pump and put it back together and no start. So I dropped tank and took the pump out and try and turn key to on position to see if pump is coming on and nothing happens. thing is fuel sending unit is attached and it is getting power. I checked with a multimeter and have power at plug 12v. should there be 2 wires with power coming one to sending unit and one to the pump itself? I thought maybe bad pump and went got a new one and no same thing no power to pump. checked relays and switched them around checked fuses and still no power to pump can't figure it out any help would be great guys.
thanks,
matthew


najah
New User

Jan 15, 2006, 10:14 PM

Post #2 of 10 (3799 views)
Re: Fuel Pump not getting power Sign In

Frown<P>
I have the same problem as in there's no power to the fuel pump. I am in Melbourne and this is mainly a USA site so I dunno if anyone can help me but I'm just trying. I've been surfing the net ALL day on this topic & the solution and booked some Haynes manuals from the local libraries to bring home later. This site seems like the best one so far for the moderator answers the questions posted.
Car: Mazda Model: 121 Metro (aka originally Ford Festiva) YEar: 1997
Checked the normal things: spark OK, fuel pump OK (just changed it in Sept since it broke down on me so I gather if it's new.. it's alright), wiring OK (I think.)
Could it be my computer? Relays? there are these little relay square-ey thingies (about 6 of them) in the hood of the car up the front and in the manual it says to check it the fuse wires are burnt-- and none of them are. Also I checked the funny little switches underneath on the driver's side.. nothing looks wrong from the manual.
Is it some kind of wiring fault?? I've researched the topic and seems to me the obvious explanations are relay problems or wiring problems.. or didn't I install the fuel pump correctly to cause a short circuit? My boyfriend's a wannabe-mechanic but can't seem to find if there's an ignition switchbox or something?? (BTW he does everything that needs to be done to the car, he services it regularly and changed the fuel pump back in Sept. He's a motorsports student so he knows about cars and I trust him. Just this instance we can't figure it out!)
Arghh I love my Mazda but this ain't no simple problem can't seem to find where the problem is!
Please help!
Thanks
-Naj


DanD
Veteran / Moderator
DanD profile image

Jan 16, 2006, 5:52 AM

Post #3 of 10 (3793 views)
Re: Fuel Pump not getting power Sign In

Ok first off you will not have constant power at the fuel pump with the ignition in the run position with the engine NOT running.
Let me try and explain; when you initially turn the ignition on, the fuel pump is activated for two or three seconds, this is called the prime cycle, it’s to pressurize the fuel rail. If the computer does not see a RPM signal it will deactivate the pump. If everything is normal; when you crank the engine the computer sees the RPM signal, closes the auto shutdown relay which in turn closes the fuel pump relay and the pump is again activated.
At the fuel pump/fuel gauge sending unit you may have three or four wires, A dark Green/Black the fuel pump power, Dark Blue the fuel gauge and one or two black both are grounds. The dark blue wire should have 5 to 7 volts on it for the fuel gage. Also check that the ground(s) are good.
A voltmeter if it’s a good quality one will not be intrusive to the system; most times that’s a good thing but if there is a wire that is all but broken or corroded and only has one or two strands still making a connection. The voltmeter will still show you a normal voltages.
The green/black wire should have power to it as explained above, but this time test it with the thing connected to the pump, by back probing the connector with a safety pin or paper clip.
You may have a bad connection that will only go open when there is a load on the system. There is one connector that some of these older vans had; have been bad for corroding. If this van has this connector you’ll find it about half way down the frame on the drivers side. It’s about one inch square and I’ve repaired a lot of them for corrosion.
Let us know what you find.
Dan.

Canadian "EH"






Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Jan 16, 2006, 11:32 AM

Post #4 of 10 (3788 views)
Off the Topic Comment...... Sign In

Najah and any reader. You mentioned "driver's side" and we silly North Amercan's don't usually think of right hand drive vehicles. This site is growing as it should and involves all countries of the world. All invited!

Would love to visit Melbourne but for me Hawaii is only half way and that's just a bit much for me. My private jet is still on back order so I'll have to wait!!Smile

That's why computers are so magical for the world, Be well, T



najah
New User

Jan 16, 2006, 3:39 PM

Post #5 of 10 (3781 views)
post icon Re: Fuel Pump not getting power Sign In

DanD,
I'm sure you have a million templates to choose from 'coz you'll get sick of replying to newbies like me! I appreciate your suggestion and will check it out after work tonight. My beau's not so good at electricals and he won't listen to my ramblings so I'll print this out and force feed him! Thanks for your help, will let you know the outcome soon.
P/S: Tom, Melbourne's great! (On par with Toronto (?) for most liveable city.. what can you say? I love it! Smile )


DanD
Veteran / Moderator
DanD profile image

Jan 17, 2006, 5:05 AM

Post #6 of 10 (3777 views)
Re: Fuel Pump not getting power Sign In

Najah I was replying to xxmatthewxx and most of what I said will not apply to your vehicle. Sorry.
Dan.

Canadian "EH"






Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Jan 17, 2006, 8:05 AM

Post #7 of 10 (3773 views)
Re: Fuel Pump not getting power Sign In

Hi - Speaking for myself, don't own this site but love it, newbies are as welcome as anyone. Heck - we were all newbies once! I wish I had hands on computer help like I did in school for auto repair!!Smile Yeh - that was a long time ago but I've yet to see a square wheel run smooth down the road. T



najah
New User

Jan 17, 2006, 3:43 PM

Post #8 of 10 (3767 views)
Re: Fuel Pump not getting power Sign In

FrownDan, last night we checked with the multimeter there was power of 25V!! Sounds a bit much. Last week no power at all. I dunno what's going on. Anyways I'll let you know what I find in the next coupla weeks. Might need to send it down to an Auto Electrician... (read: $$$ Crazy )


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Jan 18, 2006, 2:12 PM

Post #9 of 10 (3761 views)
Re: Fuel Pump not getting power Sign In

I don't know of anything in a regular car that uses 25V!! I would check your meter with a known source. T



najah
New User

Jan 18, 2006, 6:13 PM

Post #10 of 10 (3758 views)
Re: Fuel Pump not getting power Sign In

UnimpressedYeah I figured everything was a bit suss. (For non-Aussies: That means dodgy. Read: not right.)
Anyways my boy took out the fuel pump from the fuel tank and brought it to the autotech: he had a look and said "the fuel pump's stuffed." (Read: not working.) So we went and bought a new one and.. ta-daa!! My car's fine.

Thing is, I JUST changed the fuel pump back in September. Fendi says maybe he's taken out the fuel pump out of the tank too many times to check it recently that he probably stuffed it up. Is this possible? I'm still not 100% sure it's the pump but then again... my car's in tip-top condition!

Hmmm... lucky it was $173 after discount. Thanks guys, I'm sure I'll come back to this site soon!!






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