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Blazer fuel pump


rajung's Avatar
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04-23-02, 05:57 PM   #1  
Blazer fuel pump

My Daughter has a 1994 Chevrolet Blazer with a v6 and I am hopeing someone can help with a problem .
A few days ago it quit running and wouldnt restart.
The fuse for the fuel pump was blown.
Replaced , tried to start and blew again.
Can a bad fuel pump cause this or would the odds be the wiring in the fuel pump system?
I know almost any wiring problem in that area can cause this but she is known to drive on vapors quite a bit which must really play havoc on an electric pump.
Also is there a plate on the floor area for the pump or does the tank need dropped?
Thanks to all the help now and in the past.

 
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davo's Avatar
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04-23-02, 06:07 PM   #2  
Iwould suggest disconnecting the connection at the pump and turn the key on and see if it blows again.Then crank it and see if it blows if it does not it is most likely the pump or wiring inside the sender.If you replace the pump change the in tank filter and the one in the fuel line.

 
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04-23-02, 06:18 PM   #3  
Thanks
Any idea if tgere is an access panel?

 
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04-23-02, 06:36 PM   #4  
Remove the rear tank bolt and loosen the front bolt that will give you enough access.If you need wiring diagram send me a pm with email addy.

 
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04-23-02, 06:37 PM   #5  
Oh sorry no access panel.

 
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05-08-02, 04:56 PM   #6  
Well I removed the fuel tank and found a bad pump and both wires to it melted.Sender works, or did before anyway.
I repaired wires,replaced fuel pump,strainer and pulsator just for good measure.
My question is before I replace the tank I tested the pump in a bucket of water and the pump runs under a 12volt source but only when the float is at the bottom (empty) position.
As soon as I raise the float the pump quits.
I am not an idiot nor an Einstein but doesnt this seem backwards?
Low fuel, pump should quit!
My daughter must seem to confuse decimals when fueling.
One more !
At the weather pack connector at the bumper for the pump before I removed tank I had second or so current when ignition was turned on,cant remember which color wire.
Now I cant get any even though the fuse has 12volts on both sides and not blowing as before.
Thanks for all the past help.

 
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05-08-02, 05:18 PM   #7  
well it sounds like you have somehow hooked up the fuel pump to run through the sending unit or perhaps you are not grounding the unit correctly the pump should run regardless of where the float is and sticking it in water is not that great of an idea and hard on the pump, usually the purple wire goes to sending unit and grey goes to the positive side of the pump and black to the negative side of the pump perhaps when repairing the wiring you incorrectly wired it or you are hooking up your 12 volt source to the purple and grey which you only need to hook up to the grey and to ground out the sending unit to ground.

 
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05-08-02, 05:26 PM   #8  
Thanks.
The wiring to the sending unit only connects one way both ar different type of ends.
I connected the grey to the pos. side of pump and black to neg. side.
at the weather pack connector I hooked the pos. to grey and the other to neg. on voltage source.
I did not however ground pump unit(sending unit) or ground ring that usually mounts to frame.
Is this the problem?
It sounds like I should have grounded the 2 ground wires and just connected the pos.
Doing what I did, would this cause the symptom I had?
Thanks

 
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05-08-02, 05:43 PM   #9  
yes it would cause the problem hooking either ground or power to the sending unit would explain why it would only function when the float valve is at empty the sending unit grounds out to the metal and is a variable resistor when your float is at empty you are getting a decent ground to run the pump but when you raise the float resistance increases and will cause the pump not to run, if you just hook the negative to the black gound wire or to the metal part of the sending unit and the positive to the grey wire it should run regardless of float position.

 
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05-08-02, 06:31 PM   #10  
bejay
Thanks so much for the info you posted.
I will install tomorrow and post update.
Thanks again.
I have found this site very usefull & friendly by almost all users.
rajung

 
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05-09-02, 06:52 PM   #11  
Replaced tank/pump today.
Everything seems to work fine.
Daughter happy,I'm glad its gone.
Thanks to all again for advice.

 
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