I'm trying to help my uncle figure out what's wrong on his 93 ZJ, 4.0. It keeps dying on him after it warms up a bit. Let it sit 20 minutes or so and it will start up again without much effort. So far we've changed the dist, rotor, fuel filter, ignition coil, map sensor and O2 sensor. the last two were done based on trouble codes from the computer. What I'm wondering is if it's possible for the CKP sensor to go bad without storing a code in the computer? at this point I'm leaning towards this being the problem if it's possible. Only other thing i can think of would be the fuel pump or pressure regulator. But we have no gauge to test that right now. Any other thoughts? Thanks!
Well, just to update, it is possible for the CPS to go bad without storing a fault code. Finally checked the codes while the ZJ wouldn't start and it retured a code 11. god what a bear that was to change. we've got it easy on the YJ's so far the thing will fire up, but it's still running rough. spitting and sputtering on accel. MAP, coil, dist, rotor, CPS, and O2 sensors are all new. Also, we pulled the muffler off to check the cat and there's nothing in there. Some PO must have cleaned it out. now we just have to figure out why it's not running smoothly. the engine was over heated (260 redline for a few miles) and then run hot from FL to NY (though never that hot again) so I'm wondering if it's just something that was warped finally taking a dump on him. still got the fuel pressure to test though so we'll see. thanks for the help guys!
I double checked the firing order and that's as it should be. I'm not familiar with the IAC, what's that do?
It is the Idel AIR Controler. It controls the amount of air fulel mixture. If it is dirty or gone bad the jeep will not idel right or it will chug down the road not alowing the motor to rev. at very high RPM's.
ZJ 98 5.9 LTD. Lots of mods. 7" T&T's Long Arm Lift ,BFG KM2"s,35X12.50x16's,4:56's, Vanco brake upgrade, M1intake,Holley52mmTB,MikeLeach Headers,, Arb'ed HP D30,Aussie Locked rear,Procomp MX6 Shocks,Arb front,RearTR bumpers,ECT.ECT.