Number 4 misfire, 2004 Isuzu Axiom.

longboard1st

I have a 2004 Isuzu axiom that is that has a check engine light on. The engine is bogging down and burning a lot of oil and is reading a misfire on the number 4 cylinder when I hooked up the diagnostic tester to the OBD II. The positive crank case ventilator was clogged with oil, it helped cleaning the pcv but continued to burn oil and read a misfire on valve 4. When doing a compression test all cylinders are reading 95. To test the coil packs we look at the resistance on the main coil between the plug and power and all had similar resistance on them, the spark plugs had some residue on them but were still getting a spark. When we ran the engine and unplugged each pack the engine slowed with each cylinder was taken offline leading me to assume all the coil packs are doing something. When inspecting the the inside the manifold and cylinders with a boroscope they seemed to have some excess oil residue but otherwise nothing of note. I will be doing another compression test and a leak down test on it, would anybody have any suggestions how to trouble shoot the problem. I am guessing it is some misfire caused by something mechanical but I would not know how to determine what those could be. Most troubleshooting focuses on fuel and ignition but the bogged down engine coupled with the burning oil is difficult to single out.

Any insight would be greatly appreciated.

longboard1st

while I was doing a leak down test there was a noticeable amount of air coming out of the intake off of the number 4 cylinder

fendlay

I'm having the same issue with my 04 Isuzu Axiom. I have bogging under 3/4 load on the gas pedal and sometimes I hear it backfire. The misfire I am having is on the number 6 cylinder. I did all them tests as well and seamed to check out fine. My mechanic and I narrowed it down to ignition coil wiring. There are 3 wires on each coil harness. The harness that plugs into the coil. The black wire is the ground, the green and red wire goes to the PCM, and the black and orange wire went to a condenser which is located on top of the engine on my year of vehicle. My mechanic and I tested all three wires and turns out for my situation that the green and red wire does not have any load on it. We checked it with a meter. So that wire is short which runs from the harness that plugs into the coil leading deep into the main harness then into the PCM which I tried to match up where that wire was plugging into on the computer side and the wire that runs from coil 6 runs to the computer but it changed colors on me. The wire that matches that coil is yellow on the computer side and green and red on the coil side. So that's how far I've gotten with mine. So tomorrow or the next day we are going to run an out side wire to see if that fixes the problem. I also have a major oil leak. but I think that's my head gaskets or cam seals. I just know it's coming more from the front of the motor than anywhere else.

Any help is appreciated and hopefully this helps you out a little as well

AxOnTheGo

I've been having the same issue on the #4 for about 6 months with my 2004. I tested coils too but thought I'd consider the fuel side, like maybe a clogged injector. I've been running 2x the concentration of fuel detergent & I thought it was helping but hasn't solved it. I believe the injectors are inside the V under the common core so I was about to track down the gaskets when I came upon this thread. Tell me SOMEONE has solved this