Fuel pump issue

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spottedsquirl

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Hey all, my '85 max's fuel pump doesn't work like it should on the factory wiring. I have eliminated the pump it's self by wiring it directly to the battery. It pulls and primes on the battery but when on the key it sounds weak and don't want to prime. Has anyone ran a bypass to a relay or toggle? Is there anything I could do to improve the factory voltage?
 
If your pump is slow then the battery may be low. Did you verify it had power? In the On or RES position? Is the low fuel light working (you can verify this when cranking to see if it lights up while cranking)?
 
If your pump is slow then the battery may be low. Did you verify it had power? In the On or RES position? Is the low fuel light working (you can verify this when cranking to see if it lights up while cranking)?
Thanks for the reply. The battery is fully charged, I jumped the pump straight to the battery and it runs strong. When looped back through the bike it's weak. No difference between res. and on switch position even on an empty tank. The res. light does work as it should. I did have it running for a couple minutes after I went through the carbs just to hear it run. Thought the pump didn't sound right then, but didn't think much of it cause it was running. Btw, this is not the stock pump. It was already installed before I bought the bike.

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Sounds like the aftermarket pump is bad or, you have bad wiring somewhere to the pump, if it runs well on a direct wire, but not when you hook it up to the stock wire leads. Try flexing the leads from the 2 lead plug and see if it affects the pump operation. Flex them starting at the terminal and work backwards.
 
What pump is it, and why not swap it for a stock one?
I don't know the brand of pump it is, I'll have to look this weekend. I know this one works so I'm gonna pass up a swap unless I absolutely have to. Thanks

Sent from my SAMSUNG-SGH-I337 using Tapatalk
 
Sounds like the aftermarket pump is bad or, you have bad wiring somewhere to the pump, if it runs well on a direct wire, but not when you hook it up to the stock wire leads. Try flexing the leads from the 2 lead plug and see if it affects the pump operation. Flex them starting at the terminal and work backwards.
I will look into it this weekend and perhaps I will just go ahead with a relay. It'll save the amp and voltage draw from the stock setup and get more power to the pump that it needs. I do have a relay kit that I didn't need for another project. Thanks

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Don't trust it till you check the wiring. A relay is a good idea. If you have a problem with the wiring that won't put enough current to the pump, you'll probably be ok with a relay. They don't take much current to trigger them.
 
Don't trust it till you check the wiring. A relay is a good idea. If you have a problem with the wiring that won't put enough current to the pump, you'll probably be ok with a relay. They don't take much current to trigger them.
Wiring checks out. I may go ahead with the relay but it won't help with the current issue. Took it for a test run today and sure enough I didn't get but 100ft or so down the road and it quit on me. Turned the key off and back on but no fuel pump clicking. After about a minute or so the pump starts and ran about half a mile and quits again . Same as before, after about a minute it's all good again for roughly the same distance. I have a full tank of clean fresh gas and clean filter. The pump is not getting hot. I did switch from on to reserve and ran for over two miles without a hiccup. What can I do to fix this issue?

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Well when you hit the starter button, does the fuel light come on, on the gauge cluster?
 
Well when you hit the starter button, does the fuel light come on, on the gauge cluster?
It does not come on when I hit the start button with the switch in either position.

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