Topic: Help Jeep wont start!

[Greatwhite]

Okay was in the parkinlot of my local 4x4 store, just bought some bushwacker flare, (thats the only good part of this story) Got in the jeep started it and it almost imediatly died.  wont fire back up.  Called my tow truck driver buddy and got the jeep into my garage.  Now from my troubleshooting the fuel pump is not kicking on, i tried to just change the relay no luck, fuel system fuse is fine.  Now does this mean that my fuel pump is no good? even with the key on i have no presure in my fuel rail.  If this is the case how involved is replacing the fuel pump.  any ideas?

[JeepManMarc]

That sounds like a fuel pump issue, could also be an electrical issue though too.  I have had that same thing happen on a car I used to have, turns out the issue was a faulty wire midway back between the main harness and the pump itself.  However snice it just stopped out of the blue, one would think that a likely culprit would be the pump.  Not to sound like captain obvious but check your fuel filter too, that starting and sputtering sounds like somthing may be gunked up?
I dont have much experience with these issues on Jeeps, but on cars I have dealt with my fair share of fuel system issues 

[Greatwhite]

Havent checked the filter yet, but my main concern is i dont hear the fuel pump clicking on when you turn the key on  i guess im just hoping someone has a miracle cure that im to pissed off to think off at the moment that doesnt involve dropping the tank 

[Jeffy]

If you don't hear the fuel pump priming then that's probably your problem.  If your fuel filter was clogged, you'd at least still hear the pump.  Check the fuses first.  Then check the electrical lines going to the fuel pump.  Check to make sure the ground for the fuel pump is still connected.

Getting to the fuel pump means dropping the tank which can be a PITA if it's full of gas.  Then you've got to find containers for the gas.

[Greatwhite]

Any pointers on installing the new fuel pump or is it as straight forward as dropping the tank and putting it in ? any install tips would be apretiated 

[JeepManMarc]

If its like all the others I have done just be careful and double check everything.  There is a drain plug on the gas tank, drain your gas into some clean 5 gallon buckets.  Unbolt the straps, undo the filler neck and vent hose, then I always let the tank down with a small floor jack (its not heavy though)  Now there will be a cap with wires running into it, there may be 2 of these such caps, one will be the sending unit.  The larger of the two will be your fuel pump.  Unbolt it, and the entire assembly should pull right out unplug the old one, and un screw it from the bracket, install your new pump and make sure all the connections are clean the wires are in good shape as you wont want to do this again I am guessing.  Just reverse the previous steps and you should be good to go.  If you do go through with this and drop the tank, you may want to test the old pump by hooking it to a power sourse such as a car battery to see if it turns on.  Then you will know for sure if that is your problem.  Either way though I wouldnt recoment putting the old one back in if it does work, safe yourself the hassle, its just one less thing to worry about down the road.
Like I said though, I havent done one on a Jeep before, but on all the cars I have done one on the steps are pretty much the same, so the same should apply here.

[rwing1]

Before you drop the tank atleast check for power getting to the pump. Should be able to measure if it's coming OUT of the relay.... If you haven't yet, download the copy of the FSM for a 1994 YJ/XJ that's posted somewhere on here.... didn't take the time to find it again.... Your signature says you have a '95 so it will be close I think.

BUT if you do drop the tank(or even if you don't) try the FAQ/DIY thread about increasing the capacity in the YJ's gas tank by shortening the filler/vent tube........you could gain an extra 5 gallons in the tank between stops!  I been waiting for an excuse to do that myself.

EDIT: here's the gas tank mod http://4bangerjp.com/forums/index.php?topic=10.0

here's the FSM...and there is a '95http://4bangerjp.com/forums/index.php?topic=414.0

[Greatwhite]

Thanks for all the pointers guys, and the FSM should help Alot.  I will run some more tests and drop the tank and see whats going on.

[Greatwhite]

Well, bought a fuel pump module assembly from Jeep, came with the sending unit, float pick up all one drop in unit.  put it in last night and the jeep fired right up.  Now it seems to start quicker even in the mornings when it is cold, and it definatly runs better, quicker throtle response, it was all arround worth it.  Back in action.

[lanulos89]

nice glad she's running again

[Jeffy]

So does your gas gauge read properly?  This is a bit late but. If you hadn't already it would have been a good idea to do with 19/20 gallon conversion then went with a 19 gallon sending unit.

[Greatwhite]

I already have the 20 gallon tank stock.  Other Bad news however Drove the jeep to work yesterday no  problems.  Got in it to go to lunch and the same thing happened again. It started ran for 1-2 seconds and shut off and then would not start again... i called the auto electric place we use, he had me turn the key on like your trying to start it and feel if the auto shut off and fuel pump relay were clicking on and off. the were not, big problem.  Got an ohm meter out, checked for 12V at the PDC no hot lead of any kind going to the fuel pump relay or auto shut down relay with the key on, which means its getting power cut off to the fuel pump before it even gets to the relays.  So i rolled it in the shop last night and im having it towed to The auto electric shop that we use, he seems to think it might be a poblem with my PCM. we will see 

[aw12345]

The autoshutdown relais as well as the fuelpump relais have the ground side turned on by the ECM in other words the ECM controls the ground circuit of those relais you can simply jump the ground side of the relais to ground and the fuel pump should run. Or easier yet first step is see if there is power at pin 30 or B+ in the power center for both relais then look for ignition power on pin 86 or 87 one of those is ignition 12 volts while the other is the ground circuit most of these relais have a circuit diagram on them with the terminal numbers makes it easier to trouble shoot. When both relais are grounded the Jeep should run if not its not an ecm problem. Download those Factory Service manuals gives you wiring diagrams, wire colors and circuit numbers would have saved you the money for the pump, tow cost and whatever you pay the electrical shop. Would have been nice Jeep toy money 
In my book money doesn't grow on trees and simple repairs like that you can easily do yourself

Art

[rwing1]

OUCH!  Sorry to hear you went through all that and still have a problem.  This might be a really good time to dig out that FSM we told you to print/save and try to do this yourself.  Then if something happens when your too far away for a tow truck, you'll know how to get the ol' girl running again.  I hope you don't end up replacing anymore expensive parts without solving the real problem......then you'll really be kicking yourself in the pants for not getting more new Jeep parts that you could've had .  Good Luck!

[Greatwhite]

OKay got the jeep back from the Auto Electric shop, turns out that Fuel pumps are like Starters, in the way that when they start to go bad the amperage that it takes to keep them going increases. The amperage was running so high on the old pump before it went out that Fuse number 5 got hot and melted the plastic surrounding the clip that holds it in place, this made that fuse loose but didnt actually blow the fuse.  So he fixed that and also found that the crankshaft position sensor wires were routed right by the exhaust and they were melted to the point were he was amazed the jeep ran, so we were able to fix another problem before it happened. Ran me 230 bucks and all is well.  im back on the road again and can put the cover back on my truck!