Fuel Pump Relay

Tiny
JJREBHOLZ
  • MEMBER
  • 1996 CHEVROLET TRUCK
  • V8
  • 4WD
  • AUTOMATIC
  • 132,000 MILES
I changed my fuel pump and when I did I redid the wiring inside the tank. This included 4 wires, two grounds and power to the fuel pump and power to the fuel gauge. Now the fuel pump relay keeps burning up on me. The relay gets so hot that it will smoke and the truck will die. When I change out the relay it will start back up. Is it possible that the I mixed the two grounds up or is something else causing this?
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Friday, October 8th, 2010 AT 9:58 PM

50 Replies

Tiny
JDL
  • MECHANIC
  • 16,098 POSTS
My wiring diagram showed three wires at the fuel pump. The info I looked at was for a 96 K1500 5.7L engine? I also looked at the partsbook for fuel pump connector, it showed a three wire connector. Maybe there is new style and old style?
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Friday, October 8th, 2010 AT 10:15 PM
Tiny
JJREBHOLZ
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  • 6 POSTS
I dont know but One ground goes directly to the frame.
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Saturday, October 9th, 2010 AT 12:16 AM
Tiny
JDL
  • MECHANIC
  • 16,098 POSTS
It sounds like you have a bad ground oir fuel pump control module. Here are the fuel pump wiring diagrams and a guide to help you check the wiring and connections.

https://www.2carpros.com/articles/how-to-check-wiring

Please let us know what you find. We are interested to see what it is.
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Saturday, October 9th, 2010 AT 9:32 AM
Tiny
BOB HILL
  • MEMBER
  • 1 POST
I got a new fuel pump balance module fix the problem cost $54.00 Thank you so much
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Sunday, November 4th, 2018 AT 12:32 PM
Tiny
FREEBEETOWING
  • MEMBER
  • 1 POST
  • 1996 CHEVROLET TRUCK
  • V8
  • 2WD
  • AUTOMATIC
  • 333,000 MILES
I own a 1996 chevy 3500 HD tow truck, vortec 454, 4l80e trans. Well it keeps on burning up fuel pump relays, what could be making it do this
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Sunday, November 4th, 2018 AT 12:33 PM (Merged)
Tiny
DR LOOT
  • MECHANIC
  • 2,311 POSTS
Most likely a bad ground.
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Sunday, November 4th, 2018 AT 12:33 PM (Merged)
Tiny
RDCJB
  • MEMBER
  • 1 POST
  • 1996 CHEVROLET TRUCK
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 100,000 MILES
I have a Chevy 1500 and Since the end of May, I have replaced my fuel pump 3 times. I have also replaced the sending unit, wiring harness, fuel filter, 2 o2 sensors, the idle air intake valve, alternator, and fuel relay. After I replace the fuel pump, the truck runs great for about a wekk, then the check engine light comes, then about a week later, the engine dies and I have no fuel pressure and no power to the pump. What else should I check/replace to fix this issue?
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Sunday, November 4th, 2018 AT 12:34 PM (Merged)
Tiny
POWERS009
  • MEMBER
  • 2 POSTS
My fuel pump on my 97 s10 went out recently it was an electrical problem that caused mine to go out. They also had to change a map sensor and the crank shaft sensor on it. Don't know if that will help.
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Sunday, November 4th, 2018 AT 12:34 PM (Merged)
Tiny
HJC4604
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  • 1 POST
Have you cleaned out the tank? There may be water or dirt clogging the pick-up filter in the tank. If the punp can't get fuel out it can burn out or may just not be able to pump since it can't pick up fuel. Is the pressure at the rail zero or does it have a low reading. I've had 2 pumps replaced in 200,000 miles. They seem to last about 100,000.
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Sunday, November 4th, 2018 AT 12:34 PM (Merged)
Tiny
CHEVYMANSMP790
  • MEMBER
  • 3 POSTS
  • 1996 CHEVROLET TRUCK
Other Category problem
1996 Chevy Truck V8 Two Wheel Drive Automatic 332k miles

I just lost my fuel pump and put a new one in and it works fine but my truck wont satr ive checked for fuel pressure and spark and have plenty of both. I also checked the relay and its good too. Im trying to chase down the cause of the no start any suggestions? Thanks

P.S I dont know if the pcm might be on the way out with the miles it has on it?
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Sunday, November 4th, 2018 AT 12:34 PM (Merged)
Tiny
PEAR69
  • MECHANIC
  • 1,482 POSTS
If you have spark and fuel then check the gap of the spark plugs. If your computer is bad then there would not be any spark and/or fuel. I would test the ignition module considering the miles. Autozone or a place like that will do this for free.
Is the check engine light on?
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Sunday, November 4th, 2018 AT 12:34 PM (Merged)
Tiny
CHEVYMANSMP790
  • MEMBER
  • 3 POSTS
No check engine light
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Sunday, November 4th, 2018 AT 12:34 PM (Merged)
Tiny
CHEVYMANSMP790
  • MEMBER
  • 3 POSTS
I also want to try an injector pulse width test because I know I have fuel up there its acting like the injectors arent spraying but the trucks been maintained and I just put injector cleaner in it
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Sunday, November 4th, 2018 AT 12:34 PM (Merged)
Tiny
DOUGWHITE39
  • MEMBER
  • 1 POST
  • 1996 CHEVROLET TRUCK
  • V8
  • 2WD
  • AUTOMATIC
  • 150,000 MILES
After changing the fuel pump on my 1996 Chevy Silverado, and changing the fuel pump relay, it still doesn't work. Someone told me that the ignition control module could be the problem. Is it possible that the control module will keep the fuel pump from working? If not, what else could it be?
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Sunday, November 4th, 2018 AT 12:34 PM (Merged)
Tiny
SCOTTY DEE
  • MECHANIC
  • 592 POSTS
Did you verify that there was power to the pump before you changed it?
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Sunday, November 4th, 2018 AT 12:34 PM (Merged)
Tiny
FARMER34
  • MEMBER
  • 2 POSTS
  • CHEVROLET TRUCK
I have a 1997 Chevy 3/4 ton 4x4 automatic truck. The fuel pump relay is getting extremely hot. Checked the frame ground for the fuel pump and it is seems in good order. Replaced the relay with same results. Replaced the fuel pump with the same results. Removed the underhood relay box from weather box and found the gray wire has actually started melting. The wire goes to the fuel pump. Replaced the ground wire on the battery and cleaned all the contact surfaces. No recent repairs, truck has been wrecked and rebuilt. Truck is also high miles. Only OBDII code is an ignition misfire code that has been there for the 3 years I've owned the truck. Another thing that bothers me is the volt meter only reads about 12.5 volts, with a new battery. Haven't had the alternator checked yet but have a feeling it is do to a short in the system. Running out of things to try. Hoping someone might have some advice. Aprreciate any help.
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Sunday, November 4th, 2018 AT 12:34 PM (Merged)
Tiny
FARMER34
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  • 2 POSTS
Will try the oil pressure switch. It is a 5.7 with a 4L80E automatic transmission.
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Sunday, November 4th, 2018 AT 12:34 PM (Merged)
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
The computer energizes the fuel pump relay by grounding one side of the coil in the relay.

You need to check the fuel pressure, don't let the pump fool you because its coming On-it might be inadequate pressure.

Also look below this how your fuel system is wired


https://www.2carpros.com/forum/automotive_pictures/12900_oil_sending_unit_and_fuel_pump_circuit_11.gif



www. .com
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Sunday, November 4th, 2018 AT 12:34 PM (Merged)
Tiny
YOLLUP
  • MEMBER
  • 4 POSTS
95 chevy 1/2 ton. With a jumper wire in the relay I checked fuel pressure there is lots. There is no 12volt signal coming when the key is in the crank or run position at the relay to energize the relay. It does have battery power at relay. It also seems like there is no signal going to the injectors either. There is no fuel coming out when cranked.
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Sunday, November 4th, 2018 AT 12:34 PM (Merged)
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Since you know how to jumper a relay find me some spark at the pug wire and report back your findings. Don't have sparky we are not gonna have injector/s pulses. That's Y she's not starting No fuel in the combustion chamber.
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Sunday, November 4th, 2018 AT 12:34 PM (Merged)

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