1989 K5 will not start found that fuel wasn't getting to the TB, replaced filter didn't fix the issue, put a test light to the fuel pump and found very low voltage to the pump, traced wire back to fuse block very good power to the fuse block but low voltage coming out not sure what to do next. Any suggestions would be greatly appricated.
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.
Low Voltage to Fuel Pump
- Thread starter RDElliott
- Start date
zombie1969
1/2 ton status
You can check for the presence of voltage with a test light but not the amount.A dim light would be an indication of low voltage but we are smarter animals now with more advanced tools.You should have a relay that supplies voltage to the pump and if the contacts have carbon build up it will act like a resister giving the pump less than bat voltage.
It is located on the firewall just to the left (passenger side) of center. There will be a connector with a red wire dangling from it.
Don't forget there are two halves to that voltage. Where did you get your ground for the test light?
If its the same place the pump does, it might be a bad ground.
If you don't have a voltmeter, a long piece of 12 or 10 gauge wire can help locate problems.
Hook one end to a known ground and hook it to the ground of the pump. Either a separate ground wire, or the gas tank its self.
If that does not help, thenhook the end to a fused power source, and carefully hook it to the hot wire for the pump.
If it runs, then you will have to back trace the power feed. If not, then check the pump.
If its the same place the pump does, it might be a bad ground.
If you don't have a voltmeter, a long piece of 12 or 10 gauge wire can help locate problems.
Hook one end to a known ground and hook it to the ground of the pump. Either a separate ground wire, or the gas tank its self.
If that does not help, thenhook the end to a fused power source, and carefully hook it to the hot wire for the pump.
If it runs, then you will have to back trace the power feed. If not, then check the pump.
Its a common dilema with GM vehicles,the plug and wiring harness for the fuel pump often get corroded badly,some new pumps come with a new plug and a peice of harness to splice into the old harness..my friend usually just runs a new wire from the fuse box to the pump when he encounters a vehicle with gangrene wiring going to the fuel pump..and yeah,grounds are important too,especially on vehicles here that rust so fast you can almost watch them turn brown..adding another ground wire to the frame surely wont hurt..
