ktmcherokee13

i have a 96' xj with the 4.0 ho and it turns over has good spark good compression and good fuel and wont even think about firing... just turns over and over. no dtc's are thrown, and i do not know what it is!

freegdr

are you getting injector pulse

freegdr

did you check it for codes

ktmcherokee13

yes the injectors are goin just right, and its not throwing any codes. idk why! haha but its my dd so it kinda sucks

freegdr

injectors going just right ???????????? even if check engine light is not on does not mean there are not codes.....

ktmcherokee13

i scanned them all ready and theres no codes available

freegdr

im just trying to run all the possibilties thru here what do you mean by the injectors are just right,and 49 psi fuel pressure

freegdr

some cherokees have a problem with code reading did you get a code 12 or 55,and how did you read them key on key off method or scanner

tjwalker

Quality of spark must be considered.

Pull a plug again, ground the electrode, crank it over and watch carefully.

You must have a strong, blue, snapping spark. Yellow/orange/white indicates a weak spark, which may not be strong enough to start the engine (coil is #1 suspect for weak spark)

ktmcherokee13

ok... so i had spark yesterday... now its gone.. may just have been to weak? and it threw a p0505 code which it idle air control.. co i cleaned that real good and put it back in. it may be a coil...?

tjwalker

The #1 cause of no-spark is the crank sensor. The #2 cause is the ignition coil.

Test them BOTH. They can both be tested and if you have no spark, testing is usually conclusive.

ejxj96

I had the same problem and it was the crankshaft position sensor.

ktmcherokee13

it has a rather new crank censor cam sencor and coil... so heres a thought. i have a snorkle and submerge my cherokee now and then... could be a computer issue?

Firestorm500

It's tired of your abuse and refuses to submit to it any more.

Jeeps are tough but not submarines.

ktmcherokee13

this is very true....