No fuel pressure '91 MJ

[87manche]

How would i go about jumping the pump? hook it straight to the battery?

What can i do with the contaminated fuel? isnt muratic acid available at pool supply stores?

yes, straight to the terminals on the pump. Only a moment though! Just enough to make it jump.

Disposal of the old fuel is a problem. You can take it somewhere, use it to start a bonfire or kill weeds, just don't pour it down a drain.

 

[old_man]

What can i do with the contaminated fuel? isnt muratic acid available at pool supply stores?

I would bet that your fuel filter is totally clogged as well. Muratic acid is available at Home Depot and Lowes as well.

 

[kastein]

How would i go about jumping the pump? hook it straight to the battery?

What can i do with the contaminated fuel? isnt muratic acid available at pool supply stores?

I would go with the start a bonfire method, we use it frequently here.

I also keep a 5 gallon bucket I call the "5 gallon bucket of miscellaneous hydrocarbons" around, every time I replace a gas tank, whatever is left goes into it. I use it as a first-step degreaser, differential parts / tranny parts / axleshafts / other large parts go in and get hit with a brush, it takes heavy gear lube off way better than brakleen. Then I rinse the gas off with brakleen (over the bucket) and throw the lid back on.

 

[sharq]

I would go with the start a bonfire method, we use it frequently here.

I also keep a 5 gallon bucket I call the "5 gallon bucket of miscellaneous hydrocarbons" around, every time I replace a gas tank, whatever is left goes into it. I use it as a first-step degreaser, differential parts / tranny parts / axleshafts / other large parts go in and get hit with a brush, it takes heavy gear lube off way better than brakleen. Then I rinse the gas off with brakleen (over the bucket) and throw the lid back on.

great idea with the bucket. i dont have a lid for a 5 gallon bucket but i have plenty of buckets. i have dogs and they hang out while i work in the garage and yard. im concerned about them getting into something like that. i need to find me a painter with some extra lids.

 

[kastein]

Two bucks or so at Home Depot / Lowes if you can't find one. Even comes with a nitrile rubber hose gasket in the rim.

 

[joe_peters]

Delis--the buckets usually smell like pickles, but after adding some misc. liquids it won't matter. Around here they sell them with lids for about $0.50 each.

And if the pickle smell really bothers you, turn it upside down on the lawn for a day.

 

[sharq]

Does a XJ tank fit in a comanche? if i can make it fit ill be fine with an XJ pump/sender.

 

[87manche]

Does a XJ tank fit in a comanche? if i can make it fit ill be fine with an XJ pump/sender.

No, not even remotely close.

You can still get new tanks.
http://www.partstrain.com/store/details/Jeep/Comanche/Spectra/Fuel_Tank/1989/SPIJP5B.html
$136 for a new tank. Get the straps as well, they're going to fall apart when you take them off.
They show an RCI fuel sender for that tank as well, but I'm not sure if it actually fits.

I would clean that bracket/sender up and replace the pump with an XJ pump. of course this is assuming that you've verified you're getting proper voltage and ground at the harness. The pump that is in the tank might be fine, even with all that nasty, it just depends if it sucked up that mess.

I'd say for sure you're pulling the tank, and at the very least cleaning it thoroughly and coating the inside. For $150 it might not be worth the hassle and you can just stick a new tank in it.

 

[sharq]

just curious, what is it about the dimensions that make the XJ tank not fit?

 

[87manche]

The XJ tank is much flatter and wider. The MJ tank is more vertical and longer.

The width of the XJ tank will make it interfere with the driveshaft. Also the mounts at the top of the MJ tank that are molded into the bed are chaped to come down and over the top of the MJ tank and lock into the formed strap ridges on the tank. The filler neck locations are facing the wrong way as well.

Here's the XJ tank:

here's what an Mj tank looks like.

 

[kastein]

I'd honestly throw a new tank in it. Cleaning up that sending unit may take quite some time.

 

[87manche]

Does anyone know if the 23 gallon sender and the 18 gallon sender are the same? I've got a 23 gallon sender out back tat has a good pump in it. and good gauge sender.

 

[sharq]

Does anyone know if the 23 gallon sender and the 18 gallon sender are the same? I've got a 23 gallon sender out back tat has a good pump in it. and good gauge sender.

would we be able to find out from an FSM?

 

[hupo224]

wrong thread

 

[joe_peters]

Does anyone know if the 23 gallon sender and the 18 gallon sender are the same? I've got a 23 gallon sender out back tat has a good pump in it. and good gauge sender.

The 91-93 parts catalog only lists one gas sending unit for the MJ, no tank size specified.

Here is the info from the 87-90:

SENDING UNIT, Fuel ***
5200 3671 1 w/16 Gal. Tank - Carbureted Eng. - 7 Ft. Box - 1988
5200 3644 1 w/18 Gal. Tank - Carbureted Eng. - 7 Ft. Box
5200 3652 1 w/23.5 Gal. Tank - Carbureted Eng. - 7 Ft. Box
5200 3644 1 w/23.5 Gal. Tank - Diesel Eng. - 7 Ft. Box

 

[kastein]

Fairly certain they are the same, the bracket mechanical differences are fuel injected vs carbed vs diesel, electrical differences are renix vs HO, pump differences are carbed (no pump) vs TBI (4cyl RENIX, low pressure pump) vs MPFI (6cyl RENIX + all HO, high pressure pump) vs diesel (I think.)

 

[sharq]

well, i finally had a chance to work on the fuel pump/sender assembly. i took the pump itself out of its hangers and hooked it straight to the battery. the pump doesnt seem like it wants to rotate freely. like its got too much junk in there. it does act like it wants to. i can feel it try to turn but it doesnt seem to operate correctly. i tried to clean the fingers on the sender and ended up breaking one. this unit is totaled
ill be pulling the tank in a few minutes.