FNG 4.6 Long Rod

[Antifreeze2]

Cut off one of the tips on the male o2 plug and everything fits just fine. The stroker actually feels powerful and I absolutely love it. This is what I was expecting out of the build. What sucks is that I haven't had the new bung welded in yet so I am sacrificing my AEM til tomorrow. NEW PROBLEM. After driving for a while, if I'm a little heavy on the gas, one cylinder will miss once. If I continue driving harder than normal, more cylinders will miss. After the o2 install, I had not seen this problem. Just moments ago, seemed like only 2 cylinders were working at a time. Lots of missfiring. Limped it home and pulled the plugs to find white residue on all of them. I am guessing the copper autolites were too hot a plug and am now searching for a cooler alternative. I really hope the problem is just a plug. Had them gapped to .45 with my MSD coil and Magnacore wires.

[Antifreeze2]

after doing some more reading, I believe the white residue could have been caused by the really lean fuel for a bit. I figured that since the fuel changed, it shouldn't be an issue. I found a chart of heat ranges for autolite and going to try 2 steps lower from the 985 plug to a 3923 plug. According to the chart, the 985's are the only ones with a special power tip. Not sure exactly what that means, but I hope I can use the other plugs.

[SilverXJ]

You could have fouled the plugs. For plugs I would recommend NGK ZFR6FIX-11, stock # 6441 for an Iridium plug or ZFR6F-11, stock #4291 for the V-Power copper plug. You were really driving it without O2 sensors?

[Antifreeze2]

o2 sensors were out of my budget to replace. Now that I've learned much more of how all this jazz works, I understood the need for them. New plugs worked great, stroker worked great . . . for about 2 miles. Then the misfire came back. I figured I would top it off with fresh 93 octane, but no help. The check engine light started blinking and I knew that was my sign to call it a day for now. I have no idea what could have lasted 75 miles without issue and suddenly come with a vengeance. I don't think it's related to anything internal, but who knows.

Original plugs. Don't think they're fouled.

[Antifreeze2]

There's a lot of backfire out of the exhaust with this missfire. This isn't pre-ignition ping, is it? Water temp is cool at 180, oil pressure around 55 i think.

[SilverXJ]

Those plugs look fine. Check your distributor indexing. Usually on a new engine that is the main culprit of poor running.
http://www.angelfire.com/my/fan/dist_index.html

Also, you can not run a modified engine without O2 sensors. Hopefully you got lucky and didn't damage anything. As you saw it will run incredibly lean if you have stock injectors.

Oh.. and you may want to reset the PCM since you installed the O2 sensors.

[Antifreeze2]

Running neon EV6 injectors. I'll take a look at the dizzy first thing tomorrow. Swinging by a shop to have the extra bung welded on in the afternoon. I did not reset the PCM, thanks for the reminder.

[CobraMarty]

Why the .045" gap? Back down to stock. .032-.035" and see what happens. Take the MSD box out of line, I have had them go bad.

[SilverXJ]

Take the MSD box out of line, I have had them go bad.

Thats another option. I would put the ignition back to stock just for diagnosis.

[Antifreeze2]

I have the stronger ignition coil, not an actual multiple spark box. Plus, I don't have the stock coil to plug in anyway. Still trying to wrap my head around what could cause it to work well cold, then poorly hot--even though the coolant doesn't pass 185. Could be the plug gap as fuel isn't dense enough to ignite at warmer temperatures. Ran the large gap with a Jet Chip on the stock engine, decided to pull the chip but leave everything as is to get started. Just got up, let the games begin!

EDIT: Never done this before, so this is the procedure I found and will try, only disconnecting the negative instead and touching it to the positive terminal, as per a Hesco employee.

Disconnect the POSITIVE battery Terminal and touch it to ground for 30 seconds. (This is to discharge the PCM capacitors, which maintain the Adaptive Memory.)
Reconnect the Battery Cable
Turn Ignition Switch to the “On” position but DO NOT start the engine
Turn Headlight “On”
Turn Headlights “Off”
Turn Ignition Key “Off”

Very wrong and could be very bad for any computer controled vehicle. NEVER remove the positive terminal first and NEVER NEVER install the positive terminal LAST.

You should always remove the negative terminal first and install the negative terminal last to help prevent voltage spikes into the vehicles modules.

I'm not saying that every time you spark the positive terminal back on it will wipe out a ecu....but why take a chance.

But I have used many times resetting the pcm by unhooking the netative terminal and touching it to the positive terminal for at least 10 seconds. This will not short anything out because the battery is open and there will be no current flow thru it.
__________________
Hesco employee
http://www.hesco.us 205-251-1472
Jon Schaefer
2007 JK Unlimited
Supercharged 3.8
Unichip dyno tuned

[SilverXJ]

Being that it is back firing I would really suspect the distributor indexing. Something isn't firing when it should be. Mybe it wa sin a failsafe mode with reduced timing when you had the O2 sensors out. If thats fine it could be a failing sensor such as the cam or crank. I would check where you were when hooking up the O2 sensors. Maybe you bumped another connector, like the crank. Or maybe the crank sensor could be lose.

[Antifreeze2]

Rain today slowed me down a bit. Reset the pcm, didn't fix it. Gapped the plugs to .35, didn't fix it. Before it reaches operating temps, it runs perfect. Makes me doubt the distributor is indexed poorly. Saw white smoke when it started--really hoping it was condensation in the exhaust from the rain. Part of me thinks that it could be coolant leaking into the combustion chamber when the t stat opens, but I'm still full at the radiator.

[Antifreeze2]

Called the machine shop, they said it could be a laundry list of things. Pretty much anything electrical, including coils, plug wires, dizzy, and injectors. Time to learn how to use a multimeter.

[Antifreeze2]

Plug wires are good, coil is good, crank sensor gave me no resistance at all so I'm going to blame that until proven otherwise. Can't believe I have to pull out the impact gun to get it off.

EDIT: I thought I was doing something wrong to get 0 resistance when testing the sensor in the jeep. I have it on my desk and definitely 0 resistance. I take it the new sensor will have high resistance regardless of install?

[Muad'Dib]

I want to say they are suppose to be something like 250 ohms. That might be RENIX specific though so take it with a grain of salt.