Topic: Help-1994 2.5 dies sometimes

[1994 green yj]

My 1994 yj 2.5 will start up and run less than 2 miles and sputter out and die.  It then fires right up and goes a little ways and sputters and dies.  It has had an auto transmission and auto column installed in place of the stock 5spd.  The fuel filter and sock was changed trying to fix this issue along with the fuel regulator, and crank position sensor. The filter has also been bypassed trying to solve this.  It has a half azz exaust system on it right now.  It will idle forever, but once you get down the road a little ways it starts acting up.  Any ideas?  The previous owner said that it used to go 15-20 minutes before dying when it first started doing it.  When I picked it up, it went less than 100yds before doing it.  The key switch in the column is backwards "you have to turn it backwards to get it to start" and Im having that straightened out tonight.  It also has the stock 5spd computer in it.
Thanks

[sharpxmen]

i guess first you have to find out if it is the fuel pressure that causes the problem (seen that you focused on that with the fuel filter). so have a pressure gauge installed, drive it and keep your eyes on it when it dies - if it drops to below 20psi then it's either the fuel pump itself or some electrical issue that causes the pump to stop (this assuming that it would hold 30psi with the engine off and it won't bleed back - otherwise you could get mixed up on the reading). If that checks out ok (so if it is not the fuel pump & related you'll have to move on to other components like ecu, ignition, ASD (this is controlled the same as the fuel pump relay) and so on - first you need to determine what dies though - you could also have a voltmeter or even a lamp connected to the output of the ASD and/or FP relays and see if there is no voltage when it dies, then your focus would be on that part of the system - so first find out what stops it from running, then if you still didn't find the cure we can help some more based on the results. keep us posted.

EDIT: and that part with the switch backwards i don't really understand, but just maybe that contact is disconnecting due to vibrations - sounds like there was some weird work done there, usually when you have to turn the key counterclockwise is to only have accessories powered - how do you crank it? or if that is the cranking procedure how do you have "ignition on"? is there a separate contact that does that - it could be that you need to solve this first and your other problem might be resolved as well.

[justin399]

Have you replaced the sending relay? I had a similar problem last year, or maybe the year before but after changing the filter then the pump I tried this $7 part & fixed it. Good Luck.

[jfrabat]

When mine did this, it turned out to be a bad fuel pump...

[1994 green yj]

i guess first you have to find out if it is the fuel pressure that causes the problem (seen that you focused on that with the fuel filter). so have a pressure gauge installed, drive it and keep your eyes on it when it dies - if it drops to below 20psi then it's either the fuel pump itself or some electrical issue that causes the pump to stop (this assuming that it would hold 30psi with the engine off and it won't bleed back - otherwise you could get mixed up on the reading). If that checks out ok (so if it is not the fuel pump & related you'll have to move on to other components like ecu, ignition, ASD (this is controlled the same as the fuel pump relay) and so on - first you need to determine what dies though - you could also have a voltmeter or even a lamp connected to the output of the ASD and/or FP relays and see if there is no voltage when it dies, then your focus would be on that part of the system - so first find out what stops it from running, then if you still didn't find the cure we can help some more based on the results. keep us posted.

EDIT: and that part with the switch backwards i don't really understand, but just maybe that contact is disconnecting due to vibrations - sounds like there was some weird work done there, usually when you have to turn the key counterclockwise is to only have accessories powered - how do you crank it? or if that is the cranking procedure how do you have "ignition on"? is there a separate contact that does that - it could be that you need to solve this first and your other problem might be resolved as well.

You have to turn the key backwards to start it.  Just the opposite of how it should work.

[sharpxmen]

You have to turn the key backwards to start it.  Just the opposite of how it should work.

is it a different ignition key contact? or some model that was sold in bizarro world or something

[1994 green yj]

Got the ignition switch fixed today, ran it down the road today and it went 2 miles or so and quit running.  Got it started and went another 100yds and it died again.  It seems to act up more as the fuel level gets lower.  When I bought it, it went 50yds and sputtered and died.  I put a half tank in it and it started running farther before dying.  Im going to fill the tank tomorrow and see what happens. 

[sharpxmen]

easiest way would be to monitor the fuel pressure - but if you add fuel and it gets better might point to the pump (best way to tell is still with a gauge though)

[1994 green yj]

easiest way would be to monitor the fuel pressure - but if you add fuel and it gets better might point to the pump (best way to tell is still with a gauge though)

I thought about bypassing the whole system by dropping a different pump into a 5 gal gas can and hooking it up to the fuel line at the filter. 

[sharpxmen]

I thought about bypassing the whole system by dropping a different pump into a 5 gal gas can and hooking it up to the fuel line at the filter. 

you still have the FPR at the other end, but it would cover the pump and pre-filter in the tank (if you got debris in there and it's plugged).

[1994 green yj]

Thanks
The FPR is also new as of last week!

[sharpxmen]

Thanks
The FPR is also new as of last week!

be careful how you hook up that pump though, you don't want any sparks around that gas can

[1994 green yj]

Just hooked up the pressure gauge again, 22psi at idle.

[sharpxmen]

Just hooked up the pressure gauge again, 22psi at idle.

you should have between 30 and 32 (31 i think is in the FSM). if you unplug the vac tube on it should jump to 39psi. so there's your problem - since you said you bypassed the filter and changer the FPR then you could either have debris in your tank and your pre-filter plugged (but unless you have a lot of miles on it is not that likely to have that much to affect your pressure by 8 psi at idle) or you fuel pump is gone. You could unhook the return line and put a hose in it, put it in a bottle and see if anything comes out - if it's the pump or prefilter the cause of low pressure there should be nothing coming out (or very little).

[1994 green yj]

Yeah even with the vac line unhooked the pressure is 32.  I bought a new bosch pump yesterday and sock so I will be tackling that this morning.  Any tips or secrets to removing the tank?