new guy 90 xj

i bought a 90 cherokee for 300 bucks it runs but it has black smoke coming out the pipe i did a compression test wich ive never done befor on cylinder 1 it read 110 2, 120 3, 90 4, 90 5, 135 6, 120 im not sure how good or bad that is when i got the jeep it had been sitting for about three or four months any ideas.

Country_Boy

it looks like you have a hole in between 3 and 4 head gasket. so replacing that would help that out, but the others look good as long as they are all roughly consistent. and for the black smoke...if it smells like gas then it means your running rich. so id do a full tune up. (plugs wires cap rotor oil filter and air filter) and is that model TBI (throttle body Injected)? if it is then you may have a sensor problem with that, but its too much buy new so junk yard would be best. i hope this helps. i can help you with anything if you have questions.

Turbo X_J

cylinder 1 it read 110 2, 120 3, 90 4, 90 5, 135 6, 120

Head gasket.

new guy 90 xj

im going to replace the head gasket this next weekend and see how that works what sensors do you think it could be i replaced the tps this weekend and put a knew air filter in the plugs and wiers are knewer not sure about the cap though i know i need to do the oil to thanks country boy.

fishtaconc

You could have a leaking injector(s), more likely suspect would be the MAP sensor causing the rich condition

Country_Boy

its basically a vacuum sensor. if it is reading wrong air pressure then it will think "oh crap we need more fuel to compensate" just try and clean all connectors that look like they need it and check for mystery wires. maybe something is unplugged. and google does help a lot in diagnosing problems. its faster then waiting for someone to read a post.