jayzauto Posted January 23, 2016 Share Posted January 23, 2016 Ok guys 91 mj base 4.0 4wd. I've been told my fuel pumps bad. Trying to save a little money I plan on doing it my self. Well most the video and pictures I've seen show the fuel pump on to the tank meaning you gotta drop the tank. As I crawled under mine there seems to be something mounted to the side of the tank. Is this the pump? I do have pic and video of what I'm talking about but this site will not let me upload from phone. Any help would greatly be appreciated. Link to comment Share on other sites More sharing options...
Doc. Posted January 23, 2016 Share Posted January 23, 2016 If memory serves me right, the last pump I replaced on a stock short bed truck I did not drop the tank. Link to comment Share on other sites More sharing options...
Marine1Texas Posted January 23, 2016 Share Posted January 23, 2016 My 87 long bed, and 88 short bed both can be changed by not dropping tank. Link to comment Share on other sites More sharing options...
HOrnbrod Posted January 23, 2016 Share Posted January 23, 2016 Ok guys 91 mj base 4.0 4wd. I've been told my fuel pumps bad. I'm curious who told you the pump was bad. What are the symptoms? Does it run? Has it been pressure tested? Link to comment Share on other sites More sharing options...
jayzauto Posted January 25, 2016 Author Share Posted January 25, 2016 Has not been pressure texted yet. I really don't no what I'm doing. I let it set for 2 and a half months because of a brake master cylinder/ injector o ring/ tire issues well finally got around to it and fix all that. Started up ideled and revved fine. Put it in drive and has no power it back fires threw intake and threw tail pipe. So I added 2 cans of heet and topped off with new fuel and replaced fuel filter. Still same problem. Also during doing all this I put the read of the truck up on jack stands and the truck run perfectly fine in all gears up in the air but as soon as it's on the ground it's back to no power and constant back fires. Link to comment Share on other sites More sharing options...
87MJTIM Posted January 26, 2016 Share Posted January 26, 2016 Either turn off "auto correct" or use a spell checker. It is hard to follow what you're saying. Link to comment Share on other sites More sharing options...
HOrnbrod Posted January 26, 2016 Share Posted January 26, 2016 Rent a set of fuel pressure gauges from Autozone and do a fuel pressure test first before pulling the pump.. Link to comment Share on other sites More sharing options...
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