Grill block / WAI side effect?
 

I installed a partial grill block on the Little Green Car. Now I notice that there is pinging. I don't know why, but I didn't think that a grillblock would cause a Warm Air Intake effect and require a timing adjustment.

Is this in line with your experience with grill blocks?

In a year I don't think I have heard this described once. I think you probably are observing a coincidence, not a cause and effect relationship.

The 96+ Hondas should all have knock sensors and automatically retard timing, if I'm not mistaken. Something funny is going on.

Only the V-TEC models (EX and HX) had knock sensors in the early sixth gen, though maybe they all had them by 99-00. Mine is a 98 DX. No knock sensor. But the car does adjust ignition timing electronically, just not valve timing.

I've watched intake temps on my Paseo with a FULL grill block. It might get warm air while sitting at a red light, but without a bellypan and more sealing the intake temps drop right down to ambient as you get moving. I should also mention my Paseo sucks intake air from the engine bay.

Grill block
 

Did you make a hole for air intake flow?
I made a grill block for my turbodiesel car, but aldo made one opening on it, to allow cold air to get into admission.

Oldbeaver

Intake air is taken from the engine compartment. I did not do a full block. I blocked the section that is in the bumper below the license plate mount; the opening above the bumper is completely open.

I suspect that LittleGreenCar needs a timing adjustment or a knock sensor.

These Civics can also get a hard carbon buildup on the cylinder tops that the valves hit against when they open. It sounds a heck of a lot like "knock" or ping.

My wife and my carpool buddy both insisted my Civic was pinging. I tried retarding the timing to various degrees with no success. At one point I had it retarded so much that it ran poorly and gave a check engine light due to lousy combustion; I promptly set it back to a more normal amount of advance. Still made the noise but ran stronger.

Mine finally had enough valve trouble that it needed a head rebuild, and when my buddy got the head off I found a huge buildup of hardened carbon on all the cylinder tops. Easily a 1/16 inch thick of HARD stuff, which I removed with considerable effort. After the head rebuild the persistent "knock" was gone.

How do these deposits build up? Are there means to prevent or correct it without physically disassembling the head and/or rebuilding it? Is the problem unique (or uniquely worse) in Hondas?

From what I have read, it seems it is a large side effect of idling too often. For how most people drive on ecomodder, it might be a fair idea to loose mpg once every 2-3 months and drive a bit harder on the car (freeway for example) to help clear out the engine.

Seafoam helps a TON with carbon build up.

Back on the main topic, I gained a WAI effect with my grill block, but prior to the last part of the block (lower) I sealed the hood and installed an upper grill block. I have no belly pan yet. Engine temps went from 202 to about 213-220 and intake temps went from about +5F over outside temp to around +50, not quite as hot as some WAIs, but still it is warmer. I notice no ping or timing changes via scan gauge, just a MPG increase and lower engine loads :).