When its warm more than cold.

 

Now we are in business my friend. Could be upstream sensors. Not sure if there is a way to test them

 

I dont know what you mean by an enter key, this is a bare bones base 4x4 2 door cherokee 5spd, nothing power at all.

I did get a fuel pressure tester that actually works (the one i borrowed from autozone did not, the one from O'reily's did) so i hooked up to the fuel rail no pressure, i hooked up in line just after the fuel filter no pressure, just to see what was going on i unplugged a vacant end on the connector i was using and cranked the engine and gas shot out everywhere. I can hear the pump running right when i turn the key and when i crank the engine fuel is being pushed out of the fuel pump and getting out of the filter fine (i still am going to change the filter but i want to try and figure this crap out first, seems to me if the pump was failing it wouldnt push fuel out at all. but heck what do i know.
Is there anything else that could be causing a pressure leak maybe, or should i be going more towards a failed sensor that isnt reading and because of this the computer isnt telling the fuel system to pressurize?

Im going to test right off the fuel pump in a couple hours to see if anything pressurizes, are there any other tests i should be doing in addition to this?

All help is appreciated.

 

I need full info. about the fuel system in the cherokee, i.e. every thing; the tank, the fuel pump .....etc.. with thanks!!

 

I have a 1995 cherokee xj 5 speed four door 4x4 4.0 H/O w/O tow package 4 1/2 inch lift with 32s and quick disconnects....... i just had new rearend put in but the jackass put in a 3.55 (i needed 3.73) its my daily driver but also want to be able to wheel when i want to you know take the kids and wife out to have a good time fishing camping ect. not going to be doing any hardcore wheeling or anything like that just want to be nice in the mud and climb the rocks if i want too. so anyway which gear should i go with.... the 3.55 or 3.73 the 3.73 is up front.

 

So, you never got fuel pressure at the rail? What kind of gauge did you get?

You should be able to get a pressure reading as soon as you turn the key on.

 

Heres some reading on testing o2's http://www.naxja.org/forum/showthrea...en+sensor+test

 

Maybe I overlooked it but what rear end you have. FWIW get 4.10 or 4.88 instead. Well work out better for you in the long run since you have to do it anyways

 

Thanks for the link, but they look old and really dirty. Im just going to replace them this weekend.

 

That is your best bet. Even if your current one(s), especially the upstream (if you have 2), are functioning properly, they may not read as accurately as a new one which would provide the best readings giving you the best mpg.

 

Precisely why i want to change both of them! This jeep will be a DD for 40+ miles a day so ill want to get good mpgs(at least for a jeep) for a while.

Thanks for everyone's help!

 

I was unble to get a pressure reading anywhere on my fuel system. I changed the filter and now she idles (very poorly and revs up to a good (cold idle) RPM and then drops down to just about dead and somehow catches and wakes herself up again. i cant even look at the throttle much less touch it or she dies.

Is there any kind of Fuel Pressure regulator that may have gone bad or is it possible that my fuel pump isnt pumping enough and is on its way out the door? Any way to test how much fuel should be discharged from a properly working pump while cranking?

 

Then your fuel pressure tester isn't working.

If the engine is running then you have some sort of fuel pressure.

I'd get a gauge that works correctly and test again.

 

Also to build off of this i noticed that it didnt make a difference if i unplugged my IAC connector that hooks up to my throttle body, dont know if it should have changed anything or not but there was no difference, if i unhook the TPS she dies.

 

Thanks guys. I'll keep yanking on it.

I'll have to wiggle it into 4 low later.

Trying to install my Sye and the rear shaft housing wouldn't come off. Had to take it a shop and let them work on it.