Ok I feel like an idiot, but it’s getting better.
August was a hell of an infuriating month trying to fix the misfire issue. I’ve been working away from home 12 hours a day, 6 days a week; so I’ve been trying to make the best out of my free time when I get it. In reality, I really just rushed things and beat my head against a wall.
One of the first things I did to try to fix the misfire issue last month was order some new NGK coil packs. They arrived when I was away from home so I asked my younger brother to go ahead and install them to see if anything would change. What I found out later on when going to check spark plug gaps was that he overtightened the coil pack bolts to the valve cover to the point where the rivet nuts locked to the bolts and spun freely so that I could no longer remove the coil packs without removing the valve cover. 🤦♂️
I removed that 255 lph fuel pump about 3-4 times trying to fix that fuel level issue, and I had ordered another o-ring gasket every time I got it wrong. The o-ring expands when you unseal the pump from the tank, so you really need to pay attention to the pictures of fuel pump modules to make sure you attach the bobber correctly the first time. I took some of the time waiting for o-rings to be delivered to diagnose what could be causing the misfire. I decided to cut back the tape over the ignition coil wires to make sure nothing was frayed or shorted anywhere. I eventually put more tape back on the wires later on to protect them from the heat, but this whole deal would come back to kick me in the teeth later on so keep this part in mind when you read the rest of rhis.
When I finally resolved the fuel level issue, my wideband sensor was showing that the car was idling and running super lean; worse than it performed before the pump replacement. At this point the car had started backfiring into the intake if I blipped the throttle while sitting, and the car would severely limit the power when trying to take it on the road. I figured that either there may have been something else I overlooked when installing the pump or I may have had a vacuum leak somewhere. I ordered another new fuel pump, stock flow this time, and a new evap canister to compliment the new vent and purge valves I ordered previously. I installed the new goodies and still nothing changed. I bought a smoke machine and meticulously checked for leaks and never came up with anything. I took the car for a drive to autozone to buy a gas cap and see how it’d behave. Although it was running lean according to the wideband gauge, it appeared to be dumping fuel to try and compensate because I was getting 3-4 miles to the gallon and my fuel tank level was dropping dramatically compared to how it ran earlier this summer. At this point, I figured this had to be something timing related, or somehow an issue with the maf sensor and ecu not adjusting correctly. I ordered NTK cam and crank sensors, maf sensor, and another new valve cover so that I could finally get around to getting my coil packs off.
I got back home from this evening today and the new parts were all here waiting for me to install. The old maf sensor screws came off incredibly easy, so I think I had either not tightened them well enough on install or perhaps the enough vibrations had done enough to shake them loose. This time I decided to add some blue locktite just to be extra safe. The cam and crank sensors weren’t too difficult to replace, it almost made me paranoid thinking “somethings not right, its never this easy.” 🤣 I took the valve cover and coil packs out as a single assembly. In order to separate the two, I had to drill through the underside of the valve cover right underneath the rivet nuts so that I could chisel them out. Once I got the coil packs ready and the new valve cover installed, it was time to check the gap on the spark plugs. I increased the gap from .44” as per the Haynes manual to .48” as per the instruction I was given by the 2JR guys by email. The big thing I noticed here was that the spark plugs in cylinders 1 and 4 looked similar in that they were dry and blackened up to the tip of the electrode where it was whitened from the heat. Cylinders 2 and especially 3 were completely blackened and wet looking with 3 looking more sludgy. This should have immediately been a big red flag but it still hadn’t clicked with me yet.
Once everything was installed it was time for the moment of truth to go start the car and see what it does. Unfortunately the car didn’t want to start at all, and I was like “damn, the more I try to fix this thing the shittier it gets🤣.” It cranked strong, so I tried blipping the throttle while starting it but that caused it to backfire. So I knew my voltage, air, and fuel all had to be good here so the only thing that could have been wrong was timing still. I swapped the coil pack connectors on cylinders 2 and 3 and told myself “well this is either going to be a lot better or a lot shittier,” and voila it started and idled like a charm. I must have incorrectly swapped them before when cutting back the insulation to inspect the wires. It’s late now so I don’t really want to drive it around and bother the neighbors and everybody so I’m going to get back at it tomorrow, run the idle air relearn, and see if the car has any more hiccups it wants to throw at me. I may even go back and reinstall the 255lph fuel pump since I know that it shouldn’t be a problem anymore and I have the extra o-rings ready to go now.