Cd90Xj

I just recently purchased a 98 xj sport and i am having a weird problem on startup. After sitting overnight i start it and it starts no problem, then afar running for about 30 seconds i turn it off, try to turn it back on and it will not start. Then after a couple minutes when a try again it will start, but run very rough and sound like its misfiring. I have no clue what could be going on i do have a small crack in my exhaust manifold, but i am not sure if that could be effecting it or not. Anyone else had this same problem? any info would be great thanks

flyingstick

next time it won't crank, turn it off and back on about 2-3 times and see if it cranks. Could be your fuel pump.

Cd90Xj

I tried that today and no luck, it would only start after sitting for a while

justin_snider

im currently having a similar problem, mine is a 92 xj i6, havent had any luck and ive replaced distributor cap, rotor, spark plugs, and throttle position sensor. i was told possibly the crankshaft postion sensor. That will most likely be my next step.

flyingstick

A cracked exhaust wouldn't cause it. I just ordered a new header for mine this morning, it's been cracked for two years. Will it continue running if you don't turn it off? Your going to need to see if it has thrown any codes and check your fuel leak down rate. It almost sounds like some really bad leaking injectors, but you'll need to check it with a gauge.

Cd90Xj

Yea i have don't all the same stuff besides the throttle position sensor, but i don't think it is the cps because i don't think it will even run if the cps is bad but I'm not 100% sure. Are my symptoms some of the sytoms that happen with the throttle position sensor?

Cd90Xj

I did just do a taurus fan swap, and when the fan switch is on it will run for a couple seconds but when you turn it on the off position it turns right off, i read that something to do with the wiring could cause the coils to stay energized for a couple seconds. And also i am not throwing any codes, i tested all the injections and none were faulty, but i haven't checked to see if they were leaking, is the only thing i need to check it with a pressure gauge for the fuel rail?

flyingstick

yes, just a fuel gauge. hook it up to the rail and crank it up. it should have about 50 lbs. of pressure. turn it off and see how fast the pressure drops. it shouldn't drop more than 20 lbs in 30 minutes. If it does then either the pressure regulator is leaking down or one or more injectors are leaking down flooding the cylinder. pull the dipstick and see if it smells like gas.

Frizzle450

I had a very similar problem to this show up on my brothers 95 xj. Turned out to be the coil. Kind of a pain to get to the coil down on the side of the block. But it may be worth a try... Also is there a possibility you may have spliced into a wrong wire when doing your fans? Just a thought....

darknezz

check my recent thread with almost similar issues, everyone said the ckp(crank shaft position sensor) except mine really only does it when hot, though today it was pretty bad. I got the new ckp today just gotta put it in.

this is also a good possibility on yours and mine and I need to check this, Ive been suspecting my fpr for awhile.

Cd90Xj

[QUOTE=darknezz;1488914]check my recent thread with almost similar issues, everyone said the ckp(crank shaft position sensor) except mine really only does it when hot, though today it was pretty bad. I got the new ckp today just gotta put it in.





i looked at your thread and I did experience kind what your problem was once while on a trail my jeep started bogging down and almost dying but i only had that happen once, I'm gonna get a fuel pressure gauge and test that because i thought i could smell gas while under the hood. But my buddy also said that it may be the ckp so when you get that in you should let me know if it worked or not. thanks

Cd90Xj

Does a bad coil throw a code? because I'm not getting any codes?

nickxj94

could be a cps mine give me fits like i would run a day no problem then the next day it wouldnt start for two days sometimes or just die driving down the road and start back up. i replaced cps and coil put a msd blaster coil on mine it runs great now

Cd90Xj

Did you throw any codes?

gullycreeper

neautral safety switch may need to be cleand?