Replaced three fuel pumps, keeps stumbling/dying

Tiny
KATIE A TELFER
  • MEMBER
  • 1995 CHEVROLET BLAZER
  • 4WD
  • AUTOMATIC
  • 200,000 MILES
Please help! My husband is completely stumped which scares me because he knows his stuff. We have replaced the fuel pump three times in the past six months or so, he just put a new one on two days ago, and a month before that. He has also replaced the sock/filter. While he was driving at work tonight all the sudden it started stumbling and sputtering and would not go over ten mph. So now here we sit again completely clueless as to what is happening. It idles smooth but is hesitating on acceleration. We have put Autozone fuel pumps on, which I am getting mixed reviews about now. Anything you can tell us to help would be very appreciated.
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Friday, December 30th, 2016 AT 3:23 PM

5 Replies

Tiny
HMAC300
  • EXPERT
Scan for codes it is probably not the pump those are pretty reliable as they only require 9-13 psi. Seeing as this is a TBI unit check under it for a vacuum leak which is quite common on these, just use choke cleaner and spray it will change rpm if it is leaking. 1995 might be a bad year, but try jumping A and B on aldl with key on and see If check engine light flashes count flashes like one three times then two three times would be code twelve which would say it is working then get back on what the codes are if any.
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Friday, December 30th, 2016 AT 3:32 PM
Tiny
KATIE A TELFER
  • MEMBER
It will not pull any codes up.
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Friday, December 30th, 2016 AT 3:34 PM
Tiny
KATIE A TELFER
  • MEMBER
Why will it not ever pull any codes up? It never works on any scanner tools.
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Friday, December 30th, 2016 AT 3:35 PM
Tiny
CARADIODOC
  • EXPERT
Hi guys. Also consider a bad ground on the gas tank. That has been a real common problem on the smaller Blazers with steel tanks. One clue is the pump works okay for a while after the tank was removed. The ground for the pump is made through the straps that hold the tank on. To verify they are not making a good connection, connect a test light to a paint-free point on the body, then probe the side of the tank while a helper cranks the engine. Twelve volts only goes to the pump for one second after turning on the ignition switch, then again during engine rotation, (cranking or running). If the ground is bad, you'll find twelve volts right on the tank.

The fix for this is to drill a small hole through the flange joining the top and bottom halves, outside of the welded seam. Run a self-tapping screw into the hole, and connect a wire to it. Connect the other end of the wire to a screw in the body or frame rail. If that is not the cause of a dead pump, HMAC300 will continue on with the diagnosis.
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Friday, December 30th, 2016 AT 3:51 PM
Tiny
HMAC300
  • EXPERT
If you have the new type scanner it will not work because it is obd2 and has sixteen ports for it to connect to not twelve or fourteen that is why they do not work. Follow what CARADIODOC has said and get back to us. Use a jumper wire between A and B to pull codes.
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Friday, December 30th, 2016 AT 4:25 PM

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