1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

Damn Fuel Pump

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Old Apr 18, 2004 | 05:54 PM
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Damn Fuel Pump

I am still having this problem with my fuel pump. I pulled it into the garage today and hooked it up my multimeter to my fuel pump. At am idle it shows up at about 12.5 volts. Now when the fuel pump makes a whine the volts drop to high 12.2 low 12.3. The new thing that i have noticed is the thing would not stay idling for long. The volts would stay steady at about 12.5 and they would begin to climb, 12.79, 13 and my car sputters and dies. Every single time i start it, it idles, and then the volts climb and it dies.

Now this has to have some sort of a reason, what i dunno. But thats what you're for! Hopefully someone can help, this is my everyday ride.
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Old Apr 18, 2004 | 06:09 PM
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Sounds like the pump may be failing once it get warm after operating, or you have a crappy ground. Your taking volt readings off the + input and chassis ground? Try adding a new ground, see if it helps.
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Old Apr 18, 2004 | 06:17 PM
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I am taking the reading off of the plug in the storage bin it connects directly to the fuel pump. There is a positive and negative on the plug so there is no chassis ground.
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Old Apr 18, 2004 | 06:38 PM
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Well after letting it sir for 15-20 minute i went to go out a start it again. It started up and the voltage showed up and fluxuated between 12.17 & 12.19 and it was running nice and smooth. After letting it idle for about 3 minutes the voltage slowly went up and up and the idle got worse and worse. The few times that the fuel pump whined the voltage shot up about .10 of a volt. Otherwise the voltage continued to go higher and high till about 13.30 when it finially sputtered and died.

Is my problem that possibly the tank it not venting properly, and the fuel pump is struggling the more it runs to push/pull the fuel? Thats just an idea.

Anywho, please more suggestions.

WhOOPS, in my first post i said "Now when the fuel pump makes a whine the volts drop to high 12.2 low 12.3." They didn't drop they increased, my bad.

Last edited by GavinJuice; Apr 18, 2004 at 06:41 PM.
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Old Apr 18, 2004 | 06:38 PM
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I have a spare one if you want to buy one ?
jm85rx7@hotmail.com[IMG][/IMG]
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Old Apr 18, 2004 | 06:41 PM
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How much, and has it ever been used?
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Old Apr 18, 2004 | 07:22 PM
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Any other suggestions as to the increase in voltage and sudden death of my car? This really makes no sense. PLEASE HELP.
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Old Apr 18, 2004 | 08:10 PM
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Your pump might be getting enough extra voltage to make the pump over power the carb. When I say that, I mean that the pump might actually be putting out too much pressure and flooding out the engine. This happened to me on my old carb that I broke the return line fitting off of. Between the pressure from the pump and having no return line, it would actually force enough fuel into the engine to make it miss a lot. After I unhook the pump it would idle nicely for a minute or two then die of fuel starvation. Your just sending enough pressure and fuel into the carb to overpower the return line and flood out the engine.
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Old Apr 18, 2004 | 08:18 PM
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yeah, is it your pump thats stopin or the car dieing? if the cars dieing it might be that the float bowls arn't set good or the springs lossened and your flooding it. i would think that if your idling your alt. should be makin more juice therefor sending it to the pump and otherplaces. check the return hose on your carb and make sure that check valve thingy is good. or if you wanna rule out the vent problem take the cap off and start it.
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Old Apr 18, 2004 | 08:23 PM
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Well, if there is too much pressure it could just be forcing the needle valves open. Those floats don't put enough force on the needle to seal enough for even 2psi of pressure without the return line, and with the return line, its still limited by the size of the line, which isn't very big.
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Old Apr 18, 2004 | 08:32 PM
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well, my car is fuel injected
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Old Apr 18, 2004 | 08:35 PM
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well now you tell us
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Old Apr 18, 2004 | 08:52 PM
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I would think my sig in the first post and the huge *** picture of the high pressure electric fuel pump would be a good indication.
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Old Apr 18, 2004 | 09:19 PM
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Anyone have any idea or education guess to the voltage problem? Should i just buy a new fuel pump?
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Old Apr 18, 2004 | 10:13 PM
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^
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Old Apr 18, 2004 | 10:26 PM
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You know what, I never even payed attention to the box UNDER the pump. It doesn't say high pressure on the pump itself. As for the sig, I just never looked at it. My mistake.
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Old Apr 18, 2004 | 10:42 PM
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Well now that we have that covered 16 posts later, anyone have an idea to the voltage problem i am having. Remember this is a FI car.
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Old Apr 18, 2004 | 10:56 PM
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if you would just show your sig in every post, maybe it would be more noticable. and the pic didn't show on me earlier, yet it still looks like the stock pump on a carbed motor, just nicer. yet have you tried anything suggested?
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Old Apr 19, 2004 | 12:06 AM
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Well every post has been surrounded around the idea that my car is carbed.
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