Jimmy fuel tank/pump/sending unit W series (pros may want to skip) - some thoughts...


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I thought perhaps I could help save someone some time or aggravation if you choose to drop the fuel tank and swap the pump and or sender, etc. I did it this weekend so I will share some of my thoughts... The vehicle is a 4WD Jimmy SLT 1995.
When dropping the tank, use a car jack and jack it up one 1/4 pump past where it makes full contact with the tank the tank will flex a litltle (this seemed to make it easier to remove the tank straps/bolts)
Check the vent valves on the top of the tank. If they have any signs of cracking, replace them. I bought one at the stealership for maybe $30. I used RTV sealant on the tank before securing the vent it seemed to help it in terms of making it rock solid (these valves turn 1/2 way to lock in make sure you set it the right way before you turn it (dry fit it first before using the silicone).
A word about the straps... In both removal and reinstallation, do the front strap first. This is very important when you reinstall otherwise if the bracket comes out of the retainer and the rear strap is tight, you will NEVER get the front strap back on without removing the rear strap/bolt.
The filler hose connection should be made before the tank straps get tightened otherwise its too tight and a PITA. The EVAP line must be connected before the tank is raised or it will be near impossible due to the metal lines and their inflexibility.
I cleaned my tank out with warm water and dishsoap and then methyl hydrate. I let it sit overnight to dry. I washed the exterior of the tank with aluminum siding cleaner and then followed with an aluminum polish and carnubua wax (it seems excessive but I figured it might stave off the rusties for awhile. Dont bother reusing that damn lock ring for the pump replacements can be had for a few bucks and its much easier when reassembling.
If you think you need a new pump, be sure to check that damn pulsator. Both sides of that useless thing have almost an internal orange lining/washer that rips eventually and bleeds pressure into the tank rather than the line. If you think the pump is still ok, replace that pulsator with a rubber hose (3 piece and hose clamps). I may have been able to get away with just fixing the pulsator but I decided to put in a new pump (I found one with a lifetime warranty if you want the name ask and Ill dig it up).
My fuel sender was whonky before I serviced it (false empty and inaccurate under 1/2 tank) and now it works like a charm. I cleaned the variable resistor pack with alcohol and then filled all electrical molex connectors with dielectric grease. Im sure this one is obvious but if you have the spare tire mounted underneath, do yourself a favour a pull it before doing work on the tank (you will have enough room to kneel and address the tank fittings facing forwards with both hands rather than contorting too much. If you have a lift then you dont have the same issues as I do.
I also replaced the fuel pressure regulator under the plenum with the Help! kit. Make sure you use antiseize on all the fuel fittings and tank strap bolts. A word about mystery leaks in the fuel system. Put a little soap and water over the shraeder valve at the test port. I found I had a very slow leak there that I was able to find with the soap/water. I then uncrewed the valve, cleaned it off with alcohol put a little oil on it and screwed it back in. No more leaks. This leak wasnt detectible with a pressure gauge till many hours later.
Sorry if this was a waste of anyones time but I thought even if it helps one person, it might be worthwhile. if everything goes smoothly, you can pull the tank and replace the assy in a day or a few hours if you rush. As for the plenum, once you do it a few times, you can pull it in maybe 20min to an hour tops.
Thanks! Andrew.
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<HTML> <HEAD> <TITLE>Jimmy fuel tank/pump/sending unit W series (pros may want to skip) &nbsp;- some thoughts...</TITLE> </HEAD> <BODY> <FONT FACE="Verdana"><BR> I thought perhaps I could help save someone some time or aggravation if you choose to drop the fuel tank and swap the pump and or sender, etc. &nbsp;I did it this weekend so I will share some of my thoughts... &nbsp;The vehicle is a 4WD Jimmy SLT &#8211; 1995.<BR> <BR> When dropping the tank, use a car jack and jack it up one 1/4 pump past where it makes full contact with the tank &#8211; the tank will flex a litltle (this seemed to make it easier to remove the tank straps/bolts)<BR> <BR> Check the vent valves on the top of the tank. &nbsp;If they have any signs of cracking, replace them. &nbsp;I bought one at the stealership for maybe $30. &nbsp;I used RTV sealant on the tank before securing the vent &#8211; it seemed to help it in terms of making it rock solid (these valves turn 1/2 way to &#8216;lock&#8217; in &#8211; make sure you set it the right way before you turn it (dry fit it first before using the silicone).<BR> <BR> A word about the straps... In both removal and reinstallation, do the front strap first. &nbsp;This is very important when you reinstall otherwise if the bracket comes out of the retainer and the rear strap is tight, you will NEVER get the front strap back on without removing the rear strap/bolt.<BR> <BR> The filler hose connection should be made before the tank straps get tightened otherwise it&#8217;s too tight and a PITA. &nbsp;The EVAP line must be connected before the tank is raised or it will be near impossible due to the metal lines and their inflexibility.<BR> <BR> I cleaned my tank out with warm water and dishsoap and then methyl hydrate. &nbsp;I let it sit overnight to dry. &nbsp;I washed the exterior of the tank with aluminum siding cleaner and then followed with an aluminum polish and carnubua wax (it seems excessive but I figured it might stave off the rusties for awhile. &nbsp;Don&#8217;t &nbsp;bother reusing that damn lock ring for the pump &#8211; replacements can be had for a few bucks and i&#8217;t&#8217;s much easier when reassembling.<BR> <BR> If you think you need a new pump, be sure to check that damn pulsator. &nbsp;Both sides of that useless thing have almost an internal orange lining/washer that rips eventually and bleeds pressure into the tank rather than the line. &nbsp;If you think the pump is still ok, replace that pulsator with a rubber hose (3&#8221; piece and hose clamps). &nbsp;I may have been able to get away with just fixing the pulsator but I decided to put in a new pump (I found one with a lifetime warranty &#8211; if you want the name &#8211; ask and I&#8217;ll dig it up).<BR> <BR> My fuel sender was &#8216;whonky&#8217; before I serviced it (false empty and inaccurate under 1/2 tank) and now it works like a charm. &nbsp;I cleaned the variable resistor pack with alcohol and then filled all electrical molex connectors with dielectric grease. &nbsp;I&#8217;m sure this one is obvious but if you have the spare tire mounted underneath, do yourself a favour a pull it before doing work on the tank (you will have enough room to kneel and address the tank fittings facing forwards with both hands rather than contorting too much. &nbsp;If you have a lift then you don&#8217;t have the same issues as I do.<BR> <BR> I also replaced the fuel pressure regulator under the plenum with the Help! kit. &nbsp;Make sure you use antiseize on all the fuel fittings and tank strap bolts. &nbsp;A word about mystery leaks in the fuel system. &nbsp;Put a little soap and water over the shraeder valve at the test port. &nbsp;I found I had a very slow leak there that I was able to find with the soap/water. &nbsp;I then uncrewed the valve, cleaned it off with alcohol put a little oil on it and screwed it back in. &nbsp;No more leaks. &nbsp;This leak wasn&#8217;t detectible with a pressure gauge till many hours later. &nbsp;<BR> <BR> Sorry if this was a waste of anyone&#8217;s time but I thought even if it helps one person, it might be worthwhile. &nbsp;if everything goes smoothly, you can pull the tank and replace the assy in a day or a few hours if you rush. &nbsp;As for the plenum, once you do it a few times, you can pull it in maybe 20min to an hour tops.<BR> <BR> Thanks!<BR> Andrew.<BR> </FONT> </BODY> </HTML>
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Jimmy fuel tank/pump/sending unit W series (pros may want to skip) - some thoughts...
Good work. I pulled the bed on my 93 short bed / reg cab last summer to replace a dead pump.....dreading the job on my 99 2 dr tahoe. I'll file this note and any comments it receives in my tahoe manual.
By the way, how loud is the whine from your new pump and what brand did you use? The factory pump in my 99 sounds like an LM2500 gas turbine spinning at 20000 rpm.
skimmer
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sounded like a jet taking off... lasted 10 months and died... NewSkimmer... you pulled the bed to change your pump ? Our 89, 92, 94 we replaced them by dropping the tank. It was only about a 30-45 minute job to drop the tank and replace. How long did it take to take the bed off ? Last bed I tried to take off the bolts wouldn't come loose had to cut them out.
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The bed was easy to take off. Bolts were no problem. Just don't forget the two? ground wires. It only took a few minutes with help. Placed it up on some saw horses (under the rigid rails) as to not scratch the paint or bend the sheet metal. Left it off for a while...was a good time to paint all frame, gas tank, ...and wax areas you can't reach with the bed on. Also pulled of the trailer hitch and blasted/painted it.
When I put it back on....I screwed a short stud into one of the bolt holes to help pilot and align the bed. Then swapped it for a bolt.
Skimmer
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Sorry about the delayed response. The pump with the lifetime warranty is an 'AirTex'. Apparently their sending units also have a lifetime warranty but I didn't purchase one.
As for the sound of the new pump, it's fairly loud but with a very low tone and it sounds powerfull. I find that when the pump is going to fail, it will sound very high pitched almost like a squeal or metal on metal sounding like a bad bearing almost. One of the best ways to tell if the pump is taking a crap is to scan the waveform of a known new/working pump and pair it off against that of the suspect one. I did this prior to replacement and I could see noticable differences in the frequency of the response (I presume where the stator was worn or similar).
So far so good since replacement except for the rad that just cracked (Murphy's Law). This is the first rad I've replaced that has both an oil cooler and transmission cooler built in - lots of lines and lots of fun...
Take care! Andrew.
in article 7kcVh.18002$807.6728@trndny09, 69SScamaro at snipped-for-privacy@nochance.net wrote on 4/17/07 7:00 PM:

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thanks....better late than never.
skimmer

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