No power for the fuel pump

Tiny
SMASH2K9
  • MEMBER
  • 1990 CHEVROLET S-10
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 137,911 MILES
The ECM in my s-10 Blazer has no power input for the fuel pump. There is no coil reaction for the fuel pump relay. I have tested the electrical wiring, and am able get the fuel pump to run through bypassing it. My guess is that there could be an open circuit that is preventing power from starting up the fuel pump. Any suggestions on where to go from here?
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Wednesday, April 15th, 2009 AT 3:06 PM

18 Replies

Tiny
RACEFAN966
  • EXPERT
First lets start with the simple things ok. Have you check the fuel pump relay? I need you to check the dark green wire with the white stripe going into the fuel pump relay make sure there is power there. Then check the black wire with the white stripe from the fuel pump relay to make sure it has a good ground. If this checks out ok then we will go from there ok. I need to also know if you the 2.8 V-6 or the 4.3 ltr V-6. Here is where the relay will be located. On the 2.8 ltr blazer it is on the left (driver) side fender near the master cylinder. There is an A/C relay then the Fuel pump relay and next to the fuel pump relay the fuel pump test connector. On the 4.3 ltr blazer it is on the left firewall next to the power brake vacuum booster. Let me know what you find and we will go from there.
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Thursday, April 16th, 2009 AT 10:53 AM
Tiny
SMASH2K9
  • MEMBER
Yes, I have checked the fuel pump relay-there is both power and a ground going throughout. I have the 4.3 liter motor.
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Friday, April 17th, 2009 AT 2:01 PM
Tiny
RACEFAN966
  • EXPERT
Ok I understand you checked the relay's but did you do the tests that I have asked. I need to know what it is doing in the vehicle. Let me know what you find so we can go to the next test. I do not guess and just replace parts I test and replace what is actually bad. I am really trying to help. Also I need you to check the gray wire or it may be tan with a white stripe wire is doing. This wire also goes to the oil sending unit as a fuel pump cut off. Get back to me ok.
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Saturday, April 18th, 2009 AT 9:27 AM
Tiny
SMASH2K9
  • MEMBER
Checked the drk green/white wire-there is power running through.

Checked the black wire-there is a ground.

I try turning the ignition, and power is not being sent to the fuel pump.
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Saturday, April 18th, 2009 AT 9:11 PM
Tiny
RACEFAN966
  • EXPERT
The ECBM fuse powers the pump here is a wiring diagram for the fuel pump. (Below) Let me know what this wire is doing. Also is there power at the orange wire at the fuel pump relay? If you are getting power to the relay and none out then this relay is no good. Get back to me with what you find ok.

https://www.2carpros.com/articles/how-to-check-a-car-fuse

Please let us know what you find. We are interested to see what it is.

Cheers
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Monday, April 20th, 2009 AT 11:28 AM
Tiny
SMASH2K9
  • MEMBER
It was the fuse thanks for your help I cant believe I over looked that.
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Thursday, April 23rd, 2009 AT 11:18 AM
Tiny
U772307
  • MEMBER
  • 1190 CHEVROLET S-10
  • 93,000 MILES
I have a 1990 s-10 2.5 engine, I've replaced the relay and the fuel pump, also checked the wiring from pump to wiring housing on fire wall. It operated on a 10 amp fuse, it blew fuses, so I up it to a 20 amp. I fear that I burnt the pump up. What could be causing the fuses to blow.
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Tuesday, March 13th, 2018 AT 10:47 AM (Merged)
Tiny
BMRFIXIT
  • EXPERT
If no start condition and fuse is blowing as key on or cranking, process of elimination should be considered
disconnect fuel pump if fuse blows wit fuel pump disconnected pump and wiring in tank OK if not check sender unit and wiring at entry point

check for voltage at the tan/wt or gray wire
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Tuesday, March 13th, 2018 AT 10:47 AM (Merged)
Tiny
U772307
  • MEMBER
The fuse blows after I drive 15 minutes and sometimes 45 minutes
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Tuesday, March 13th, 2018 AT 10:47 AM (Merged)
Tiny
WRENCHTECH
  • EXPERT
Probably a bad fuel pump.
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Tuesday, March 13th, 2018 AT 10:47 AM (Merged)
Tiny
STEVELOCK
  • MEMBER
  • 1992 CHEVROLET S-10
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 200,000 MILES
I have no power running to my fuel pump, need to know what to check for fuse, relay. Changed fuel pump in tank there are two wire's running in to tank and two wire's grounded from frame to top pump out side. Well replacing pump in tank there was two wire's with a clip that run from top of pump to a clip to the bottom off the pump were rotted almost off which were touching together. Not sure if the wire's shorted something out or if there was a different problem.
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Tuesday, March 13th, 2018 AT 10:47 AM (Merged)
Tiny
RASMATAZ
  • MEMBER
What color wires are they?
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Tuesday, March 13th, 2018 AT 10:47 AM (Merged)
Tiny
STEVELOCK
  • MEMBER
There is two wire's purple and litte grey going in to top fuel tank. There is two relays driver side engine compartment not sure if they are the wire's running from pump but one run's in two each relay.
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Tuesday, March 13th, 2018 AT 10:47 AM (Merged)
Tiny
RASMATAZ
  • MEMBER
The gray is the power feed to the fuel pump
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Tuesday, March 13th, 2018 AT 10:47 AM (Merged)
Tiny
JOEG
  • MEMBER
  • 1987 CHEVROLET S-10
Im having trouble with the fuel injection on the truck. I checked to see if it was spraying fuel and it wasnt. I put a new fuel pump and injector in the truck and I got it to spray if I direct connect the injector to the battery. I then ran new wires to the ecu and got it to run I shut the truck off lost spark fuel pump and injector so now it just turnes over and nothing. So my question is what effectes the inector and what pins do the inector wires go into for the ecu? I also put a new fuel pump relay in.
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Tuesday, March 13th, 2018 AT 10:47 AM (Merged)
Tiny
TOBYU
  • MEMBER
Try things back the way they were wired and try an ignition module. The GM have a "pip" terminal on the module that controls the injector firing.
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Tuesday, March 13th, 2018 AT 10:47 AM (Merged)
Tiny
2CARPROS-ARCHIVES
  • MEMBER
  • 1991 CHEVROLET S-10
  • 175,000 MILES
Wont run replaced fuel pump, relay, tbi
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Tuesday, March 13th, 2018 AT 10:47 AM (Merged)
Tiny
ASEMASTER6371
  • EXPERT
Start with basics. You need compression, fuel pressure and spark.

Test and tell us what is missing

Roy
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Tuesday, March 13th, 2018 AT 10:47 AM (Merged)

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