500 dollar Cherokee

[Jrama]

My buddy recently aquired a 500 dollar cherokee...and guess what..it won't start properly, not that it started when he bought it. Either way, It only does cold starts and then will stall out after 10 minutes. you must then wait an hour while it cools down before it will start again..with some difficulty. The gas peddle must be depressed to the floor to get her to start. Once running and idling it does idle nice and smooth with no problems! but when put in gear it will stall out. You can rev the engine nice and high with no stalling. Replacing wires and plugs helped her run more smoothley but did not aid in fixing the problem. Next up is a new rotor and cap. there seems to be good fuel pressure in the rail and the fuel pump you can hear work when turning the key. Thought i would also mention that the engine is a 1994 4.0 from a ...Jeep.  So basically we are thinkin its down to the sensors..does anybody have any idea which sensor would most likely be at fault. Or what is at fault in general?  any advice would be great. Also odd is the fact that it dripped out a nice load of oil...then stopped leaking and hasn't leaked since even after making sure the oil was topped up...maybe it was just a collecting pool dumping off as it was sitting on a slight angle. but in the end i now have a nice stain on my driveway

We are going to take an actual measure of the pressure at the rail on monday, and more details are sure to come as we try new things and listen to suggestions.

[cLAY]

The CPS is a good place to start. Try searching www.naxja.org for more XJ specific info.

[jcolindunn]

I'm the buddy... check out the thread I made on naxja.org for a little more detail on the problem. Free case of beer for anyone that wants to come down and diagnose the problem successfully!

http://naxja.org/forum/showthread.php?t=1004505

[YoungFluff03TJ]

*sigh*

[Jrama]

Ok replacement of the tps lead to better starts and you can drive when cold and it won't stall puttin it in gear.

Current relavent info.....

Truck will idle forever and a day
Truck starts great from cold in park or neutral
Truck has difficulty starting when warm..starts with white smoke
Truck smells like it is running very rich
Massive Misfires when put in gear when cold but holds idle
will stall out when engine is warm and put in gear
Will almost stall out when gas peddle depressed when engine is warm.

Thoughts...??

[Jrama]

I am thinking that the smoke is just unburned gasoline still in the cylinder. Due to the very rich smell of the exhaust combined with just the general smell of gasoline when it starts (note no gas smell until it starts) even when running the pump. I am now leaning towards a o2 censor, map censor or maybe....iginition coil? or cps?.....yeah. Maybe there is a leak in the intake manifold? Either way any thoughts or opinions are strongly encouraged!

[esi]

Pull your dipstick and put a lighter to the oil on the dipstick. If it starts to crackle and spark you have antifreeze in your oil and probably in your cylinders. Something to check with the white smoke coming out. And maybe when you put it in gear and load up the engine you lose compression and it dies.

[raf2379]

have you done a compresion test on the cylinders? if you did what are the numbers? and if you did not, where does your buddy live, i might be able to swing by with a compresion tester and check it out.

[JackstandJohnny]

you can rule out ignition. cps and coil are fine if it fires at all.  can you rev the engine at all?  or does it stall etc?