92 Civic VX Spark Plug Fouling?

[GasSavers_TomO]

Click HERE for Civic VX lean burn info. That will also show you the operating voltage of the LAF which from the sounds of it you were checking O2 signal from chassis ground. At operating temps those voltages sound like they are within spec.

[cmlamb2vx]

Another twist that may or may not be affecting my plugs fouling. I have noticed that my engine never quite reaches maximum operating temps. It does get hot enough to raise the temp gauge on the dash to about the middle of the gauge and to give me good heat inside, but the radiator fan never kicks in and the temp. needle can actually drop on cold mornings when coasting downhill. Shouldn't the engine get up to operating temp in about 5 minutes or so just idling and stay there? It is not a problem with a stuck open tstat as the lower radiator hose does not get hot meaning the stat hasn't opened. I did do a no no and had the tstat replaced with an aftermarket one several years ago. I have already ordered a genuine Honda part and will put it in. I think I need to check my timing as I had replaced my distributor recently and it may have gotten off. But was wondering how much if any a cooler running engine might affect FE and plugs.

[GasSavers_TomO]

Originally Posted by cmlamb2vx

But was wondering how much if any a cooler running engine might affect FE and plugs.

Cooler than optimal running temps = lower FE. It's a direct correlation as well. So if your actual coolant temps are hanging around 140?F instead of 190? your FE will suffer quite a bit.

[dkjones96]

I work heavily in the ignition field. The company I work for manufactures plugs!

The insulator on the plug should be white if your engine is running right and you have the correct heat range. I pulled plugs from my car to check on them after 15k miles and still had an almost perfect white insulator. Perfect heat range. If you don't fix that 'your car doesn't get up to full operating temps' thing I'd recommend going to an NGK 4 instead of the 5s you are running.

I can't believe how off center that one center electrode looks in that one picture.

Does your car have a cold start injector? Have you checked the injectors? Those two cylinders look like they're running rich. You can see ash on them from them firing but it looks like too much fuel is causing those chambers to run cooler and leave deposits on the plugs.

Your O2 sensor is probably fine. The other cylinders look like they run fine, even though they look cooler than optimal.

[PurpleHaze]

Lots of on-the-money advice has already been given.

Go drive to a radiator shop, making sure the car is good and warmed up. Once you are sure that things have gotten as warm as they can, leave the car running, go grab a radiator tech from inside and have him come out and use an infrared gun on the relevant engine parts. Now you know what temps you're really running and can make decisions about thermostats.

If replacing the thermostat doesn't do much for the problem, it's time to start thinking about leaky injectors. Something is dumping fuel into the two middle cylinders, but if the temps aren't right then it might be the computer.

Note: Advice from a Honda expert familiar with your ride takes precedence over the very general advice I just gave.




Final scary possibility: Head gasket has let go somehow between #2 and #3 cylinders and is letting oil in. I don't think I'd worry if I were you though.


My money's on old and knackered plugs causing your problem. The rust on your old plugs is a sure sign that it's high time for the trashcan for them. Everything else is probably fine and those two plugs just aren't firing right anymore.

[cmlamb2vx]

So I should probably get the injectors checked for proper operation paying special attention to the center two. What does this involve?

If my injectors were leaking, would this also cause my engine to run cooler than normal? I drove my car home from work today (about 12 minutes) and the lower radiator hose was still cold. Temp gauge appeared normal, heat inside was fine, but lower hose was cold. Weird........but got to be a reason..........

[Danronian]

Originally Posted by cmlamb2vx

=I drove my car home from work today (about 12 minutes) and the lower radiator hose was still cold. Temp gauge appeared normal, heat inside was fine, but lower hose was cold. Weird........but got to be a reason..........

If you temp gauge gets about to the middle, that is normal. Any higher is not normal for a Honda, and would be too hot in fact. Only time I have ever seen a Honda temp gauge go above half is when I had a blown head gasket.

I would suspect the coolant temp is fine.

You might get some more MPG if you replace the t-stat with the correct higher temp 195 unit that the VX is supposed to have from the factory.

The lower hose being cold is normal.

For your spark issues I would replace the plugs then the plug wires. I would go with Honda wires or NGKs (the blue ones). I've used others, and none last as long as those two and none fit better.

[cmlamb2vx]

Hey, thanks for the info, Danronian. I've already gotten the correct NGK plugs and wires. The correct Tstat is in transit as we speak. I suspect this could be contributing. I need to check my ignition timing, too, I think.

[cmlamb2vx]

Originally Posted by Danronian

If you temp gauge gets about to the middle, that is normal. Any higher is not normal for a Honda, and would be too hot in fact. Only time I have ever seen a Honda temp gauge go above half is when I had a blown head gasket.

I would suspect the coolant temp is fine.

You might get some more MPG if you replace the t-stat with the correct higher temp 195 unit that the VX is supposed to have from the factory.

The lower hose being cold is normal.

For your spark issues I would replace the plugs then the plug wires. I would go with Honda wires or NGKs (the blue ones). I've used others, and none last as long as those two and none fit better.

Being just a newbie, would you please explain why the lower hose being cold is normal? I guess the way I thought things worked is that not too long after the engine heats up, coolant would have to begin flowing to the radiator to keep things from overheating. BTW, does the coolant flow from lower to upper or the other way? Thanks.

[cmlamb2vx]

Well, ignition timing is good. Car seems to be having better FE since new NGK plugs and wires although have yet to confirm. Mileage so far this tank is at about 125 miles and the fuel needle is still just a hair below the "F" mark which is better for the car. I did fill up with premium though and added a bottle of fuel injector cleaner. The engine operating temp still seems low to me because I have yet to see the radiator fan operate. I know it (fan) works as I have jumped the connector with battery voltage and have also checked out the switch. The lower radiator hose is still cold. My genuine Honda tstat is to arrive today so I'll put that in hopefully tomorrow, but may have to wait a bit if my dear wife goes into labor which could be any moment literally.