IAC replace and throttle body cleaning results

[trillobite]

Update: Tinypic is STILL down, so I will post images later. isitdownrightnow.com also reports that tinyPic is down today.

I woke up this morning, and found that the weather was a perfect 82*F outside, and sunny, and as many can understand, this resulted in an itch to dig into an engine. For a while now, I have been wanting to replace my IAC, as the idle is a bit irregular, which was triggering my OCD like mad. So, I finally got to do it! While I was in there, I also cleaned the throttle body, and all vacuum passages.

What I noticed was, when I pulled the upper half of the intake off, my EGR passage was highly restricted, if not blocked completely, despite not having a check engine light, or any codes.

So after spending hours spraying cleaners on the throttle body, and scraping thick carbon with a screw driver, the results were FANTASTIC! Engine knock upon acceleration was gone until at WOT, acceleration improved dramatically, and my idle is finally silky smooth!

I still need to double check my knock sensor, and find the ohms spec for it, but I have a feeling that it's always going to have a little bit of a ping or knock under WOT, as it has 250,000 miles, and probably has carbon built up in the cylinders.

Luckily I caught the EGR passage clog early, as I was able to remove the large chunks of carbon with just my finger tips, and a screw driver. Many people will wait until it's completely clogged, which causes you to have to either remove the intake completely, or use a vacuum to suck up the carbon deposits while cleaning.

 

[Nam1911a1]

Does the knocking sound weird at high RPMs? I have never had a vehicle that knocked/detonated.

My f23a1 has 211k miles and pulling strong. I plan on cleaning the EGR, IACV, and vtec solenoid the same day I do a valve adjustment.

 

[trillobite]

Does the knocking sound weird at high RPMs? I have never had a vehicle that knocked/detonated.

My f23a1 has 211k miles and pulling strong. I plan on cleaning the EGR, IACV, and vtec solenoid the same day I do a valve adjustment.

I guess "knocking" isn't a word that is really proper in terms of the sound which is produced. Manufacturers say that the engine is "knocking," but I personally believe that the better term is "pinging." It almost sounds like bits of metal hitting the pavement, or just chattering metal in general, and not really a "knock." I was personally able to become familiar with the sound, as I have been working on my chevy 350 for quite a while now, and timing it properly actually requires you to find when the engine "pings," while going up hill, or under load, then backing off the initial timing.

To hear it, I have to roll my windows down, and drive up near a curb, as the stock sound insulation inside our accords is good enough that you can't hear it through the floor. I basically listen for the sound reflecting off the curb.

I am suspecting that my knock sensor may be bad, as usually the computer will back off the timing and prevent the engine from pinging, but who knows, maybe the computer is set to only retard the timing enough to prevent complete catastrophic failure of the engine. Maybe with a good knock sensor, the engine will never ping, or at least not loud enough that you can hear it.