GoHuskies

I had my Jeep stolen and recovered and half the cables were pulled out. After reconnecting all of them and replacing some missing ones the jeep is mostly running, but the 5th cylinder isn't firing. I checked the spark plug (it sparked against ground), but when I unplug the injector nothing happens, as in the engine doesn't sound like its struggling harder. When I use the injector wire for the 6th cylinder for the 5th one I hear an improvement, though of course not as good as when the 6th cylinder wire is hooked up to the 6th cylinder. This leads me to believe that the connector or wire for the 5th cylinder injector is broken or shorted, which is extremely believable given the wire looks horrible and is held together with tape already.

My question is, should I try to find the short or break in the wire and try to repair it, or should I just pull the wire from a pick and pull and replace it somehow? I'm quite a beginner, so I'm not quite sure how I should go about this and don't want to start splicing wires ***** nilly. Any advice or resources would be appreciated!

Saudade

First, check the connector to make sure there's no corrosion or loose terminals. I would also check the connectors on the PCM.

Each injector gets 12v with the key on and then grounds through the PCM. The PCM completes the circuit when it's time to fire each injector. You could use a voltmeter or test light to make sure the B+ side (DG/OR) has 12v.

There's a splice in the main harness somewhere between #5 and #6 injector. This provides the 12v to each injector. If you don't get 12v at the B+, perhaps the splice came apart.

If you need to replace the connector, they are easily available online or even at a local autoparts.

GoHuskies

Put the key on and checked the connector against the battery ground, since I’m not sure where the PCM ground is (just looks like a closed black box to me). All the injector connectors showed ~7.5 V on one side from the battery, including the working ones. So I rammed some jumper wires down the broken one and while the car was running jumped the leads to the injector and it sounded like the problem was solved.

I guess its just a bent lead or something in the connector, so I’ll go grab a new one. Am i right in understanding that with the connector disconnected, the injector is receiving no power and is thus wide open, so my exhaust should be super fuel rich and smell horrible? Or is the gas coming out my exhaust caused by some other problem?

lawsoncl

Other way around. It needs power to open. So bad connection = no fuel to that cylinder. Pumping air into the exhaust will trick the O2 into reading lean and though.