oldblues

hi
i need to replace the sending unit in my fuel tank , 98 12v 2500 4x4 auto qc.

called dealer and ask if they stock it ?

dealer said he needed to know what pump was in the tank so he could look up the corect unit .

he said could not tell by vin no ?

so do i got to drop tank to find out what pump / send unit i have ?

fuel pump,lift pump,injection pump ?

TIMMY22

on a 98 12v, the only thing that should be in the tank is a fuel module.

They are probably confusing it with a 24V.

ask them for one for a '97. seems to me there was a plug issue with late '97 early '98. one had 4 conductors and one had I think 6 conductors.

rattlerbob5.9

Yours being a early 98 and a 12 valve will only have a mechanical lift pump on the engine and a p-7100 mechanical injection pump. Just tell them you got the GOOD one! There was someone else on here a few weeks back with a similar issue getting a sending unit i think the problem lies in the # of pins for the wireing plug in. You for sure have no pumps in the tank.

oldblues

OK!
thanks . no third pump .

also is there any advantage going to a pump in tank ?

i think i heard something about this ?

thank you !

rattlerbob5.9

NO in the tank pump for you for any reason-never !!

chop342

To intall a pump in the tank you have to install the 3rd gen sending unit. If you want higher fuel flow or volume just install a fass pump without filters, guys around here buy them all the time for $425 for the fass 95GPH pump and no filters. This setup will work just fine with a stock engine setup, but for a 12v i wouldn't bother with anything other than what is on there from the factory unless you are making some serious power.

chris

TIMMY22

To save yourself alot of aggrivation, I would squeeze in between the bed and the chassis in front of your drivers tire. shine a bright flashlight in there and either count the wires going into the plug or unplug the module and count the pins.

When you go to dodge, ask them to bring one out from a 97 and an early 98. Now you know what you are looking for.

They will not mention this but there are refurbished modules that they will probably not stock (have to order) for half price.

You can get at that puppy 2 ways...

1. Disconnect plug and fuel lines, loosen the straps and drop your tank (your'e going to want to run it down low on fuel).


OR...



2. Remove 6 or 8 bolts that hold your bed on. Put the ones on the passengers side back in only a couple of turns. disconnect Taillight harness plug near bumper, one ground strap front passengers side of bed and hose clamps on fuel filler. Jack/lift drivers side up 2 feet or so and prop it with a 2x4 (not that heavy). replace module.

3. while you are under there, I recomend looking at the brake line that runs between the tank and the chassis. This is known to pop there. if nothing else, take a 48" piece of new brake line, get some caps to block the ends. Work it in there and secure it with both ends protruding past each end of the tank. Now, when that sucker pops some day, you have a 15min job instead of a 2 hour job. Also, not a bad idea to clean the top of the chassis rails and quickly hit them with some POR chassis paint.

Have fun!

infidel

You have to specify you have a diesel, the gassers all came with an in tank pump.

the.hogman

This past weekend I dropped the tank in my 98 12v and fixed the fuel gauge sending unit. As said before, there is no pump in the tank on our trucks.
The problem with the fuel gauge sending unit is on several threads in this forum as well as the fix. Do it. It is cheaper.
I took a different route on the fix from the ones listed by welding a tab onto the bracket that goes over the float arm. No need to go to the hardware store when you have a mig and a little piece of metal. You'll understand when you get the unit out of the tank. Simply welded a little tab with a hole in it that goes over the float arm pivot. Holds the flaot arm against the contacts so that the sender works. Took five minutes and saved me a trip and $$.
Enjoy.

Joseph H. Smith

My Dodge was made early in the production year (mid 97). I have gone under warranty a couple of times with the sending unit problem. Dodge has done several modifications to the sending unit assembly in the tank. If the unit in your truck has never been changed then the vin will work. If you are changing the whole unit and not just the float arm then it does not matter what unit you have in it now as they should sell you the latest version which plugs right in. Now having said that if you want to change just the float you will have to know which sending unit assembly you have installed as with each modification the float arm changed and it is not interchangeable with other versions (i.e. a -A or -B etc.) The last version put into my truck was an "F" which was physically different then the version removed which I believe was a "C". When I went to fix it myself I ordered just the float by my vin and they sent me the float for the original sending unit the truck had new. Not the same as the sending unit on it now which is the "F" version. Also the earlier versions had an assembly for diesel and a different assembly for gas but later versions are combined so the same unit is used on both diesel and gas.

mopower

Yep, no tank pump, just the module. The float arm on the new sensor I got looked different than the one I took out, but I clocked it so it didn't hit anything and it works perfect.

I just went through dropping my tank and changing my module for a different reason, but I can tell you that depending on where you live the winter may have taken its toll on the fuel inlets at the module if they are steel. There is a plug issue too. 98 and up have a 4 pin, the older ones have an 8 pin. The sender is only two female crimp connect type pins though, so if you only need a sender, you won't have to worry about the plug. Just a heads up to look at the fuel lines while you are there, and the filter on the bottom of the module should be changed too.

If you have the room I was told its easier to pull the bed than to drop the tank.

schoust

I did mine recently I droped the tankl pulled the module and changed the little potentiometer and that was that,when your down there make sure you look at the steel lines that go into the module and make sure there not rusty,oh and check all the lines while your at it.....