'95, 2.5L, YJ #4cyl miss.

[PapaJ]

'95, 2.5L, YJ #4cyl miss. has comp., spark and new injector. code 27 so I cleaned connector at computer. ???

 

[Bounty__Hunter]

Here's some help I gleaned from other forums:
"After much intense probing and testing, The hall effect breaker for the ignition was burnt along with a cracked cao. This lead to a spark leak between 1-4 in the cap casusing a mis fire that lead to a code 27 odd code to drop but it did. I droppped a new cap rotor wire plugs and hall effect runs like a million bucks."

" I cleaned up the plug contacts with a cleaning spray and re-installed. I cleared the pcm again after installing and I haven't yet seen any codes after a few quick trips. The jeep's also running wayyyy better.

I checked each injector plug one at a time with the DVM.
With the key on (priming) one pin on the plug would read 5v to ground. Running, the other pin would read between 0 and 1v. They all tested this way, so I'm thinking that the wiring is good."

 

[PapaJ]

New cap, rotor, wires,injectors, injectors all spraying,150#compression, cleaned computer connection.

 

[PapaJ]

and new spark plugs, sorry I forgot that.

 

[PapaJ]

black oily plug after 1min or less run time, no smoke, gota get leakdown tester.

 

[JPNinPA]

Stuck valve. Leaky valve guide? Also check the signal to the injector , that it is pulsing.

Other than these check the ccv valve and tubing if they are blocked. Blocked lines will lead to improper pressure in the valve train and may push oil where you don't want it.