Question about 1998 GMC Envoy

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What size is the nuts on fuel feed and return lines for 19998 gmc envoy

I.m trying to disconnect the feed and return fuel lines going into the spider injection system inside the plenum. I know the fuel line coming from underneath the truck has a built in 5/8" nut but the connecting nut infront of the bracket the feed and return lines connect to, I don't know what size they are. I know they are bigger than 17 mm open end wrench I have. I'm trying to disconnect this connection to see if there is a forgien blockage since ther is no fuel at the strator valve but when I cycle the key you not only hear the fuel pump run but there is fuel before and after the fuel filter. any info on the connecting nut's size would be helpful since I couldn't find anything about that in the haynes repair manual.

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4 Suggested Answers


6ya staff

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Posted on Jan 02, 2017


Ricardo Loranca

  • 552 Answers

SOURCE: Flare nut wrench size?

try metric size. a flare wrench is an closed end wrench with a little **** in big enough to to slide over the line and then around the bolt its grabs mor of the bolt than a regular wrench

Posted on Dec 13, 2008


Ronnie Wilson

  • 1596 Answers

SOURCE: have a 1995 gmc yukon 2dr i have change the fuel

On a NO Power to FUEL Pump Problem One Must ALWAYS Start from the Begining of the THAT CURCIUT, This Being the Fuse , Then The FUEL PUMP Relay , And Then WIRING , and LAST Is The PUMP Itself. Here is Info on the RELAY. rejakwilsoin @ < is my Email Address if you want More info Feel free to Contact me.

The Fuel Pump Relay is located in Underhood Fuse Relay Center. The Underhood Fuse Relay Center is located on the LH rear of engine compartment, on fender.


  1. Protective cover.
  2. Retainer, if installed.
  3. Electrical connector.
  4. Relay by depressing bracket clip at rear of relay, or removing bolts from retaining bracket.
  1. Relay.
  2. Electrical connector.
  3. Retainer.
  4. Protective cover.

Posted on Nov 02, 2009



  • 14 Answers

SOURCE: 6.2 diesel will not bleed diesel

Make sure all lines are light when turning engine over.While turning engine over loosen the a line closes to pump or the fuel filter.You should get some fuel.Then continue on all lines working farther away.

Posted on May 02, 2010

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1. Remove rear seat bench

2. Fold carpet forwards

3. Fold back rubber mat

4. Remove the nuts and fold back metal cover

5. Disconnect electrical connector

6. Release and disconnect fuel feed and return lines

CAUTION: The fuel gauge must roughly indicate zero before the left tank opening is opened. Large quantities of fuel may emerge upon opening. If necessary, keep the left tank opening closed and feed an extraction hose through the right service opening to the left tank half and drain the fuel out of the left tank area before proceeding.

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9. Disconnect line to fuel filter

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