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Fuel Pump problem?

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Old 01-24-12, 02:57 PM
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Fuel Pump problem?

83 RX7 12a with stock nikki....heres the problem. Car is sitting in my shop for paint and body work. Have been working on dash/stereo/etc so key switch has been on some. Always remember hearing the fuel pump running when the key was in "run". Decided today to start the car as it hasnt been cranked in a week or two. It started, then died after about 20 seconds, then wouldnt refire. Noticed there is no sound from the fuel pump. Checked the wire to the fuel pump, its getting power. Didnt have time before i went back to work to do anything else, except hook the battery charger up (I have drained the battery working on stereo/etc). Questions are....could the fuel pump be bad? Could I have flooded the car by leaving the key in run too long with the pump running? Thinking I will pull the fuel lines at the carb and check to see if the pump is working tonight? Any tips, ideas on what to check or do???? If I have to replace the pump, whats recommended? Thanks!
Old 01-24-12, 03:12 PM
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nope as the Nikki setup has a return line unless there is crap caught between the needle and seat. You checked and have power to the pump, I'd check the ground before condemming the pump.
Old 01-24-12, 03:21 PM
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Originally Posted by 13x
nope as the Nikki setup has a return line unless there is crap caught between the needle and seat. You checked and have power to the pump, I'd check the ground before condemming the pump.
Thanks. Theoretically anytime the pump has power and gro und it should run, correct? Will see what it does this evening and if I don't hear it running will pull it and bench test it.
Old 01-24-12, 03:25 PM
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yes it could get power but if ground is not good to complete circuit won't work

kind of like having one wire to a speaker it doesn't work untill you hook up the other
Old 01-24-12, 04:04 PM
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Originally Posted by 13x
yes it could get power but if ground is not good to complete circuit won't work

kind of like having one wire to a speaker it doesn't work untill you hook up the other
Gets weirder....got home from work figured I would go check to see what was going on.....turned key on, no fuel pump noise at all. Unplugged the connector under the bin and checked with a test light for power...yes, power is there when the key is on, as it should be. Plugged the connector back together and figured I would check the plug connection to make sure power was getting thru...on the hot side, it was, test light came on. For some reason I decided to touch the ground side, test light came on, and pump started running feebly...whats up with that???? Is the second wire not a true ground? Is the fuel pump grounded under the car???? And why was it barely running???? Definately sounds like a fuel pump prob to me now, just not sure what....

Edit: Think I might have figured out the problem. Got out the old FSM and studied the wiring diagram. The fuel pump grounds thru connector X-15...which is a ring terminal that just happens to be located in the rear hatch area next to the power hatch release, which I removed the other night, and I know i disconnected that ground wire. So hopefully, thats the problem. When I can get back to the car i will check that and see. Beats pulling the pump.....thanks for putting me on the ground search.....

Last edited by 83Limited; 01-24-12 at 04:23 PM.
Old 01-24-12, 04:26 PM
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I beleive the other wire is grounded back inside the car, slow and feeble si a sign of a poor ground. Ever see a light that is kind of dull and someone wiggles the wires and it gets brighter? that would have been a poor ground
Old 01-24-12, 05:53 PM
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Originally Posted by 13x
I beleive the other wire is grounded back inside the car, slow and feeble si a sign of a poor ground. Ever see a light that is kind of dull and someone wiggles the wires and it gets brighter? that would have been a poor ground
Hooked the ground back up in the tail and all is fine.....bad ground...thanks for the help!
Old 01-24-12, 06:01 PM
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no problem nice to know the older dudes can still be usefull lol
Old 01-24-12, 06:12 PM
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Originally Posted by 13x
no problem nice to know the older dudes can still be usefull lol
Older dudes...lol....know how that goes, been on memory lane with this car...originally owned it back in the 80's when i was in high school....feels weird to redo stuff you did to a car 25 years ago....
Old 01-24-12, 06:42 PM
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oh that is cool hopefully didn't take too much to get her the way you remember
Old 01-24-12, 06:54 PM
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Originally Posted by 13x
oh that is cool hopefully didn't take too much to get her the way you remember
She isnt in too bad a shape....paint is toast, but body is fine, mechanicals so far are ok. Worst so far has been carb rebuild, but thats to be expected. Overall she is pretty much just like I sold her in 88...just a little "shabbier" but complete...so wont take too much to get her lookin like my avatar again. (avatar is 1987, sig pic is 2011)
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