Mangonesailor
I'm Awesome
This is a tutorial for replacing the fuel pump in a 1996 and 1997 GMT 400. I'm pulling out a Spectre (that I put in while stranded this week) and putting a new Delphi in (replaced under warranty!)
First, I did the bed hatch cut per this thread by shelbyt.67 : https://www.gmt400.com/threads/fuel-pump-access-panel.11423/
However, to improve on his method, move your most-forward cut in the bed another 1/2" from the front wall, and extend the left side of the hole to the next "hump" in the bed corrugation to give you room for removing the ground wire and for getting your flare wrenches on the fittings. This will save you time and frustration.
First, pull the fuel pump relay and relieve fuel pressure from the engine-side. This depressurizes the rail ONLY. You will still have pressure from the regulator to the pump!!!!
Pic of tools needed:
Air gun, 3/4" and 5/8" line wrenches, flathead screwdriver, 13mm sockets, needle nose, brass punches/rods/tube, hammer, petroleum based grease, dielectric grease. You may want some penetrate oil for the fittings and time if your pump has never been removed. Possibly a pick as well.
I went ahead and disconnected everything electrically. The bolt is a 13mm hex and the plug just unplugs.
First I loosened the small clamp on the small tube, then the large hose just needs to be loosened from the pump side. Mine is pliable enough that I could just pull it off and push it aside.
Next, the lines. They are both 3/4" hex on the engine side and 5/8" on the pump side. Get those loosened and out the way. THE BIG LINE WILL HAVE PRESSURE BEHIND IT! Once it is loose SLOWLY remove it or else you'll take a shower of gas to the face... wear safety goggles or a face shield (uvex makes a nice one, with oxy-fuel shades you can install as well). Check to be sure the O-rings come out of the lines.
Once those are done loosen the retainer ring on the pump housing. Use compressed air to get dirt away from the hole.
To pull the pump in one move turn it so it will come out like this:
Clean the spot where the o-ring will sit, slide the new o-ring into position on the new pump and just moisten it with petroleum jelly.
Put the new pump in the same way.
Put the new retainer ring on, then wet the top and bottom so that it will be easy to install. Tighten the pump into place.
Next, use your petroleum jelly to wet the o-rings and fitting nuts, as well as the threads and tubing the nut slides over and pushes against. This will give you a nice tight seal and keep the plating on the tubes from galling. (Also helps with future replacements). My pump came with o-rings on it and extras in a bag. Keep them. I think the fit at the fuel rail as well.
Before you put the lines on look down inside for bits of the old O-rings... You don't want that in your filter. Pick the bits out carefully if you must. I used a screwdriver. When you tighten the lines ONLY TURN THE NUT! Do not turn the engine side of the line as this will twist the O-ring around and may damage it!
Install the remaining two lines and clamp them down.
I used two star washers with my ground, you do what you want. I put them on in this order top to bottom: Bolt, star washer, ground, star washer, bracket for plug. This should give you a ground that'll last a long time. Use a good amount of dielectric grease on this connection to keep it from rusting.
Plug it up and power it up a few times by turning the key on/off to prime the system and you're good to go! Just don't forget to check for leaks!
Hopefully this helps out someone in the future. I'm not responsible for any errors or accidents you make of your own doing of you follow this. You do it at your own risk!
First, I did the bed hatch cut per this thread by shelbyt.67 : https://www.gmt400.com/threads/fuel-pump-access-panel.11423/
However, to improve on his method, move your most-forward cut in the bed another 1/2" from the front wall, and extend the left side of the hole to the next "hump" in the bed corrugation to give you room for removing the ground wire and for getting your flare wrenches on the fittings. This will save you time and frustration.
You must be registered for see images attach
First, pull the fuel pump relay and relieve fuel pressure from the engine-side. This depressurizes the rail ONLY. You will still have pressure from the regulator to the pump!!!!
Pic of tools needed:
You must be registered for see images attach
Air gun, 3/4" and 5/8" line wrenches, flathead screwdriver, 13mm sockets, needle nose, brass punches/rods/tube, hammer, petroleum based grease, dielectric grease. You may want some penetrate oil for the fittings and time if your pump has never been removed. Possibly a pick as well.
I went ahead and disconnected everything electrically. The bolt is a 13mm hex and the plug just unplugs.
First I loosened the small clamp on the small tube, then the large hose just needs to be loosened from the pump side. Mine is pliable enough that I could just pull it off and push it aside.
You must be registered for see images attach
Next, the lines. They are both 3/4" hex on the engine side and 5/8" on the pump side. Get those loosened and out the way. THE BIG LINE WILL HAVE PRESSURE BEHIND IT! Once it is loose SLOWLY remove it or else you'll take a shower of gas to the face... wear safety goggles or a face shield (uvex makes a nice one, with oxy-fuel shades you can install as well). Check to be sure the O-rings come out of the lines.
You must be registered for see images attach
Once those are done loosen the retainer ring on the pump housing. Use compressed air to get dirt away from the hole.
To pull the pump in one move turn it so it will come out like this:
You must be registered for see images attach
Clean the spot where the o-ring will sit, slide the new o-ring into position on the new pump and just moisten it with petroleum jelly.
Put the new pump in the same way.
Put the new retainer ring on, then wet the top and bottom so that it will be easy to install. Tighten the pump into place.
Next, use your petroleum jelly to wet the o-rings and fitting nuts, as well as the threads and tubing the nut slides over and pushes against. This will give you a nice tight seal and keep the plating on the tubes from galling. (Also helps with future replacements). My pump came with o-rings on it and extras in a bag. Keep them. I think the fit at the fuel rail as well.
Before you put the lines on look down inside for bits of the old O-rings... You don't want that in your filter. Pick the bits out carefully if you must. I used a screwdriver. When you tighten the lines ONLY TURN THE NUT! Do not turn the engine side of the line as this will twist the O-ring around and may damage it!
Install the remaining two lines and clamp them down.
I used two star washers with my ground, you do what you want. I put them on in this order top to bottom: Bolt, star washer, ground, star washer, bracket for plug. This should give you a ground that'll last a long time. Use a good amount of dielectric grease on this connection to keep it from rusting.
Plug it up and power it up a few times by turning the key on/off to prime the system and you're good to go! Just don't forget to check for leaks!
Hopefully this helps out someone in the future. I'm not responsible for any errors or accidents you make of your own doing of you follow this. You do it at your own risk!
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