Engine/Transmission (1994 - 1998) 97 Fuel Sending Unit Replacement Info

[LJHagen]

I've been advised to familiarize myself with the type of fuel connections I'm going to run into when I drop my tank to R&R the sending unit... The book lists 3-different types of connectors, one of which requires a release tool... Anyone actually know what kind of connections a 97 Longbed standard cab fuel tank will have waiting for me up there?

 

[Andy Redmond]

Should have a plastic clip that you can squeeze on either side, while gently wiggling off the supply or return line. The supply is the larger 3/8" id and the return is 5/16". Be careful this plastic can break easily. I've sold fuel lines and fuel tank modules to several DIY's that used the bigger hammer approach. Just take your time and be patient, it'll work. I like a 2x8x36-48" to place on the floor jack to gently let it down, particularly if you have more than a couple of gallons left inside the tank.



You should have the 100ohm sending module, ck for zero at the two terminals on the tank module at "float up" and 100 +/- ohms when its down at the bottom, to assure you new sender works (tan and light blue 22 ga. ? wires)



I usually remove the elec. connector first to gain more clearance, gently pry the red lock out then squeeze the release and gently wiggle the insulator outward from the module port. A dab of diletric grease will aid re-assy.



A strap wrench is handy for removing the plastic nut. The rubber tank grommet and nut are usually re-usable.



Good luck

Andy

 

[LJHagen]

Awesome info! Fortunately, the new sending unit came with that gasket, so I'm crossing my fingers it'll go easily... ($38 for the unit and gasket from mopar4less.com).



Hey, is the fuel system pressurized like a gas system is? If so, anyone know the bleeding sequence?

 

[rrausch]

I like Mopar4less! Before I knew about them I got my last fuel sending unit at a local Dodge dealer for about twice that.

 

[Andy Redmond]

Add at least five gallons of fuel, press rubber bulb on the transfer lift pump (drivers side of engine above the starter and below the fuel filter) about 25 times. It should bang off and run rough and continue running. Should it die, loosen the m6*1. 0 bolt (10mm socket) on the output of the fuel filter, opps yours has a cartridge style, 7/16" socket on one of the plugs on the top and work the primer until you get some fuel, tighten it, then if it doesn't crank and run, you might have to loosen an injector nut (3/4" or 19mm) until you see some fuel, if it acts like it wants to crank, tighten the nut until snug, clean the area with brake clean etc. then crank run until it smooths out and check for leaks at any connection that you opened.



A job well done.



Andy

 

[Turbo Thom]

Andy. Good info. I found when I tried to let the tank down to the ground, the lines were pushed into a retainer on the frame. My old hands were almost not strong enough to pull them out. Also, when I removed the entire unit, there was fuel caught inside the module. Me on a creeper, guess where the fuel went as I tilted the unit for removal? Oh well, live and learn.



. . Preston. .

 

[johnrv4]

I know exactly what Preston means about the fuel trapped in the tank module unit. Luckily, it didn't get on me, just all over the garage floor. Then I got to listen to my wife comment "It stinks in here" for the next week. Another little bit of advice. If your fuel lines coming out of the tank are metal(on the top of the tank module), and the truck has been subjected to road salt, you might have a hell of a time getting the connectors off even after releasing the plastic clip. Living in the salt belt, I've pulled three apart that were an absolute nightmare to remove. What happens, is the steel line starts to rust underneath the sealing o-ring on the line. The rust pushes the o-ring against the plastic coupler(on the hose) so tight, that the coupler won't budge. I've fought with a few, and then did one that had plastic lines coming out of the module which released very easily.

 

[LJHagen]

One more quick sending-unit replacement question...

You can tell how much I drive this truck that it's taken this long to put 500-miles on this tank and FINALLY run the fuel down! Now that I'm getting ready to drop it, one last thing... do you disconnect the fuel lines before or after dropping the tank? Can you reach them when it's still up there? If not, how far down can you come before you run out of line?



Thanks guys!! (Wish me luck, since I'll be doing this outside!!)

 

[Andy Redmond]

You can let it down a bit (tip the rear down) to gain more access to the fuel lines and electrical connector.



Before you start pressure wash the top of the tank to keep the fuel system clean and fod out of your eyes as you work. After it drys then disconnect everything.



Giddy up. . let us know how it turns out

 

[LJHagen]

It's Done... In more ways than one, unfortunately!

Thanks to all for fantastic advice for replacing the sending unit! Went off without a hitch (and luckily, it only had 2-gallons left in the tank!). I used one of those motorcycle jacks that have become so popular lately, and it worked great.



Only bummer is, even though I did an OHM check on the new sender, gauge still reads zero... Fuses look good too... Since I'm getting ready to part with 'er (buying a house :{ ), guess I'll have to go to the gold-plated dealer on this one... . This is gonna hurt!



Thanks again guys!!

 

[Andy Redmond]

Ck. your factory service manual for troubleshooting the fuel gauge on the gauge panel.

 

[LJHagen]

unbelieveable

What were the odds... the brand new, sealed-box, Mopar sending unit was bad... nice...

 

[Andy Redmond]

"You should have the 100ohm sending module, ck for zero at the two terminals on the tank module at "float up" and 100 +/- ohms when its down at the bottom, to assure you new sender works (tan and light blue 22 ga. ? wires)"





Now do you know why I suggested in our earlier posts that you ck. it while the tank was on the ground and the fuel module was out of the tank?