Fuel pump quit...help - The 1947 - Present Chevrolet & GMC Truck Message Board Network

69BUCKET · 07-24-2018, 12:35 PM

5.3/th350 in a '69....put little over 100 miles on it with no issues and love the way it ran.

Went to start it to show my brother, fired right up, as usual....then just shut down. Tried to fire it up, but pump didn't buzz to prime system like usual. In line fuse for pump is good, 4 30a fuses for system are good. What i did notice was one relay isn't getting switch on power. I jumped power to the switch on power for that relay hoping it was bad, but no buzzing from fuel pump. Tried a new relay, still no switch on power.

Any ideas on what to try next? The relay does have constant power...but no switch power. Even when jumped, no buzzing from pump. Need some help.

BR3W CITY · 07-24-2018, 12:41 PM

If its not getting switched power, then you need to backtrack the switched source your using and see where the power isn't flowing. What are you using to trigger the relay? ignition on, the ecm command, an external switch?

69BUCKET · 07-24-2018, 12:49 PM

Quote:

Originally Posted by br3w city

if its not getting switched power, then you need to backtrack the switched source your using and see where the power isn't flowing. What are you using to trigger the relay? Ignition on, the ecm command, an external switch?

it was a 4-wire harness and wired it with ignition on...

69BUCKET · 07-24-2018, 12:53 PM

I figured when switch is on and didn't fire pump, i would jump power to it to see if it would fire...but nothing. So even if i get power to the relay, nothing is happening.

Custom 68 · 07-24-2018, 02:24 PM

Can you tell if the relay "clicks" could it be bad? I see you have replaced it. What about the ground? The relay and pump needs to be grounded good. and check your other grounds too. They can be a bit finicky.
Dave

69BUCKET · 07-24-2018, 02:50 PM

Checked grounds...block, firewall, battery, rad.support, fuel pump, all good....next?...

BR3W CITY · 07-24-2018, 03:08 PM

Put hot 12 to the pump and throw a meter on it to see what it draws. If its making no noise but drawing amps, then its seized

69BUCKET · 07-24-2018, 04:11 PM

On it....

69BUCKET · 07-24-2018, 05:17 PM

Pump is spinning as it should when 12v is applied....now what?....

69BUCKET · 07-24-2018, 05:24 PM

Wiring for pump does as it should...12v for couple seconds...then goes down...

69BUCKET · 07-24-2018, 07:26 PM

Figures...wire connections at the pump...��....the orginal nuts it came with didn't fit and the connection i came up with was loose....long day for a silly mistake...carry on...nothing to see here....

jessemthompson · 07-24-2018, 08:22 PM

Quote:

Originally Posted by 69BUCKET

Figures...wire connections at the pump...��....the orginal nuts it came with didn't fit and the connection i came up with was loose....long day for a silly mistake...carry on...nothing to see here....

It happens to the best of us. I know I’ve had plenty of these things happen to me. At least you figured it out.

07-24-2018, 12:35 PM	#1
69BUCKET Registered User Join Date: Oct 2017 Location: Newton Posts: 216	Fuel pump quit...help 5.3/th350 in a '69....put little over 100 miles on it with no issues and love the way it ran. Went to start it to show my brother, fired right up, as usual....then just shut down. Tried to fire it up, but pump didn't buzz to prime system like usual. In line fuse for pump is good, 4 30a fuses for system are good. What i did notice was one relay isn't getting switch on power. I jumped power to the switch on power for that relay hoping it was bad, but no buzzing from fuel pump. Tried a new relay, still no switch on power. Any ideas on what to try next? The relay does have constant power...but no switch power. Even when jumped, no buzzing from pump. Need some help.

07-24-2018, 12:41 PM	#2
BR3W CITY meowMEOWmeowMEOW Join Date: Sep 2009 Location: MKE WI Posts: 7,128	Re: Fuel pump quit...help If its not getting switched power, then you need to backtrack the switched source your using and see where the power isn't flowing. What are you using to trigger the relay? ignition on, the ecm command, an external switch? __________________ *'66 Short Step / SD Tuned / Big Cam LQ4 / Backhalfed /Built 4l80e / #REBUILDEVERYTHING* MY BUILD THE H8RDCPTR //\\ MY YOUTUBE CHANNEL REV J HD

07-24-2018, 12:53 PM	#4
69BUCKET Registered User Join Date: Oct 2017 Location: Newton Posts: 216	Re: Fuel pump quit...help I figured when switch is on and didn't fire pump, i would jump power to it to see if it would fire...but nothing. So even if i get power to the relay, nothing is happening.

07-24-2018, 02:24 PM	#5
Custom 68 Registered User Join Date: Nov 2001 Location: Springfield, MO Posts: 2,928	Re: Fuel pump quit...help Can you tell if the relay "clicks" could it be bad? I see you have replaced it. What about the ground? The relay and pump needs to be grounded good. and check your other grounds too. They can be a bit finicky. Dave __________________ Dave 1968 Custom Chevy with turbo charged 5.3 gen III 4l80e swap 1967-71 GMC 3/4 ton long step 4x4 (not sure what year exactly?) "A good friend will bail you out of jail...but a true friend will be sitting next to you saying "that was frekin awesome". "If it doesn't fit force it...If it breaks then it needed to be replaced anyway!"

07-24-2018, 02:50 PM	#6
69BUCKET Registered User Join Date: Oct 2017 Location: Newton Posts: 216	Re: Fuel pump quit...help Checked grounds...block, firewall, battery, rad.support, fuel pump, all good....next?...

07-24-2018, 03:08 PM	#7
BR3W CITY meowMEOWmeowMEOW Join Date: Sep 2009 Location: MKE WI Posts: 7,128	Re: Fuel pump quit...help Put hot 12 to the pump and throw a meter on it to see what it draws. If its making no noise but drawing amps, then its seized __________________ *'66 Short Step / SD Tuned / Big Cam LQ4 / Backhalfed /Built 4l80e / #REBUILDEVERYTHING* MY BUILD THE H8RDCPTR //\\ MY YOUTUBE CHANNEL REV J HD

07-24-2018, 04:11 PM	#8
69BUCKET Registered User Join Date: Oct 2017 Location: Newton Posts: 216	Re: Fuel pump quit...help On it....

07-24-2018, 05:17 PM	#9
69BUCKET Registered User Join Date: Oct 2017 Location: Newton Posts: 216	Re: Fuel pump quit...help Pump is spinning as it should when 12v is applied....now what?....

07-24-2018, 05:24 PM	#10
69BUCKET Registered User Join Date: Oct 2017 Location: Newton Posts: 216	Re: Fuel pump quit...help Wiring for pump does as it should...12v for couple seconds...then goes down...

07-24-2018, 07:26 PM	#11
69BUCKET Registered User Join Date: Oct 2017 Location: Newton Posts: 216	Re: Fuel pump quit...help Figures...wire connections at the pump...��....the orginal nuts it came with didn't fit and the connection i came up with was loose....long day for a silly mistake...carry on...nothing to see here....



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