Whats up with the 96 XJ? & Crank but no start problem!

[90zxdriver]

Well since I have been trying to figure out my lack of fuel problem I am finding out that my 96 is like no other. Heres what I discovered today;
- I have a 96 style gas tank with a 96 style fuel pump assembly (not sure of what the actual internals looks like, haven't removed it yet) but I have the 97+ style wiring harness (5 pin), not the 3 pin harness found on the 96 and older.
- I have the 97+ style relays and fuse block under the hood even though Jeep, napa, autozone and carquest all say I have the 96 and older style (only option listed in their computers).
Whats up with my Jeep? Transition year or something?

Now for the problem. I bumped into a tree a few weeks back, not very hard about 15mph, just enough to crush my bumper but nothing else. At this point the jeep stalled, fuel gauge went dead and it would not restart.
- I have a nice bright blue spark
- I have swapped all relays into the starter slot and the engine cranks everytime so all relays are good.
- I have power to two out of the five pins in the fuel pump relay when the key is in the 'run' position (see pic). 5.1v and 6.1v... is this right... should I have 12 volts?

- Dead fuel gauge
- Sometimes (and ONLY sometimes) if I leave the key on for a few minutes I will get a slight trickle of fuel out of the schrader valve on the fuel rail but usually I will just get nothing out of it.

I'm thinking fuel pump but want a second opinion before I go through the trouble of dropping the tank for nothing since it is full to the brim! I also find it strange the gauge is dead since the fuel pump and sending unit are two different units. Any help is greatly appreciated.

 

[joe_peters]

Two different units, usually sharing the same ground. Check for power at the pump and test the ground.

 

[90zxdriver]

Common ground that could have knocked loose... never thought of that! Any idea where it is and how I test it?

 

[joe_peters]

Its back near the tank. Use a multimeter to check for presence of volts and ohm function to test for a ground open. Don't have the ESM for your year, but there should only be three wires coming out of the tank--power for the pump, the ground, and the qauge sending unit which is a variable resistor.

So you should find 12v, zero resistance for the ground and something between 1 and 88 ohms (not exact) for the sending unit.

 

[90zxdriver]

there should only be three wires coming out of the tank--power for the pump, the ground, and the qauge sending unit which is a variable resistor.

Yeah, for a 96 there SHOULD only be three wires but I have 5. I just ran out at 2am to verify and took pics to prove that my XJ is 'different'

http://img24.imageshack.us/img24/5194/0315090153b.jpg
http://img17.imageshack.us/img17/6176/0315090153.jpg
http://img18.imageshack.us/img18/2685/0315090153c.jpg
http://img21.imageshack.us/img21/4757/0315090154a.jpg

If I'm not mistaken this is the setup for a 97+ XJ

 

[90zxdriver]

I finally made some progress!!!! After some great advise I recieved on here I crawled under the xj and checked my ground and it was just hanging there. (see pics)

I'm guessing that it is suposed to be attached to the top of the fuel pump assembly unit and with the rust on it and the force of the impact it got knocked off thus not grounding the unit resulting in my inop fuel pump and sending unit.

Now, what do I do about this? Since the tank is full of gas I don't think I should be running a grinding wheel to get back down to metal (spark + gas = me no longer here!) Also, once I get it all cleaned up, how do I reattach the ground? It feels sooooo good to finally be making some progress after 2 weeks of nothing!

I know most 96's don't have a fuel pump setup like this, just remember that mine is "different" haha.

I'm running down to autozone now to get a new fuel filter... it would be awesome to have a few suggestions when I get back! Thanks!!!

 

[joe_peters]

You can use sandpaper to get some bare metal.

I would solder on a longer piece of wire and locate a spot on the unibody.

 

[90zxdriver]

I found an abrasive buffing wheel for my dremel tool... its not a metal wheel, kind of like a tough cloth (sort of) I think I'm going to try using this to remove the rust.

Now, do I ground that wire that is hanging there to the frame/unibody or does the tank need to get grounded or both? She might actually start today!!

 

[winterbeater]

Do you have an ohmeter? If you do, verify that you have a good ground in that broken wire. Test from that wire to the body for continuity. If good, just solder that wire back to the flange. Otherwise solder a new wire on and ground it to the body with a screw.

 

[wim hoppenbrouwers]

Hallo. Is the sending Unit not electrical isolated from the tank and chassis by the pumpseal?
So, I think you need to reattach the solderlip with groundwire to the pumpbody.

 

[90zxdriver]

Hallo. Is the sending Unit not electrical isolated from the tank and chassis by the pumpseal?
So, I think you need to reattach the solderlip with groundwire to the pumpbody.

Yep, this is EXACTLY what I was told by a Jeep tech today! I told him my problem and before I could even finish he said the ground wire rotted off. Now I just need some half way decent weather to fix it in,

 

[winterbeater]

Just drill a small hole into the flange and sheetmetal screw it!