what exactly is this vacume reading and all that stuff?

 

Started to barely misbehave lastnight when I got off work. Picked up a honda tech with a laptop and took him for a drive. And of course, the car purred like a kitten, no problems at all. He said all the readings looked good but he was going to send a couple snapshots to Honda to see if they saw anything different.

He did mention that the oxygen sensor was switching between open loop and closed loop as I drove. He thought that was incorrect but was going to check on it. Anyone know? Theoretically it should start in open loop when the O2 sensor is cold and the go to closed once it's warm adn never switch back, right?

 

The car appeared to drive the same in both open and closed loop mode. It would switch randomly every couple minutes or so and I would never have known the difference if not for the laptop. What exactly does this affect?

And could that possibly have an effect similar to the symptoms we've been getting? Suttering under acceleration, etc.?

 

well if vtec engages but not as strong could that be the problem?

 

This statement would indicate to me that the technician thought that the O2 sensor was bad, perhaps. I thought the ECU would go into open loop if it thought that a particular sensor was bad. Open loop just for that sensor, that is. If the oxygen sensor was thought to be bad, the ECU would put the A/F mixing into an open loop value rather than measuring the A/F ratio. By this, I mean that the ECU would use a predetermined value for the A/F ratio. I have heard this referred to as a "limp home" mode.

I would say that any sensor should not be switching back and forth between open and closed loop. The communication between a sensor and the ECU forms a servo loop. When the ECU goes into the open loop mode, the feedback between the sensor and the ECU isn't working properly. Since the ECU can't read the feedback from the bad sensor, it uses a predetermind value that should be close to what it would normally be, but there is no feedback from the sensor, the feedback loop is open.

 

Hello Again! I know its been a week i didnt post but sorry there was a problem with my internet connection. Like i said in my post before, i was going to get some more parts changed on wednesday and thursday, well i did.
So lets take a look at the overall:
Problem:
Loss of power after around 20 or 30 mins of driving. The car looses half of its power like you read in before threads.

What i did to solve this before this week:
-Greddy Iridium Spark Plugs (another friend of mine has no problems with them)
-100 Octanes (98 US Octanes) 5 star unleaded used all the time.
-Valve adjustments
-Injectors cleaned
-MAP sensor changed
-Fuel Pump Changed
-Fuel Filter Changed
-Coils changed

What i did this week was (after reading the list Hecash sent)
-Vacuum Control Valve changed
-02 Sensors (both primary and secondary) changed
-Vacuum lines checked, my mechanic said there was nothing wrong with them
-Air Control Valve changed
-Evaporative Cannister and the valve related to it, changed.
-EGR Valve changed
-PCV Valve changed
-Cam Shaft Sensors (both) changed
-Gas Cap changed
-Fuel Pressure Regulator changed
-Air charge tem sensor changed
-Catalytic Convertor changed
-Exhaust system (after cat) changed, switched to stock.

After doing all these i tested the car for two days, guess what? DID NOT HELP.

My mechanic also said the vacuum lines were ok, he doesnt think there's something wrong with them.

Now i'm wondering, after all these things i did, what THE HELL IS WRONG WITH MY CAR? I actaually feel like crying.

Now i have questions. First of all i thank all the people again for helping me, i'm sorry but i expect more help from all of you!

-Someone posted about changing the spark plugs for another time, what do you think about that? the ones im using are Greddy (made by NGK) Iridium sparks,
another friend of mine use the same, he reports no problem about them, i asked him again, nothing wrong! What do you think?

Whats the difference between the air control valve and the idle air control valve?
I got the air control valve changed, my mech said they are the same but i dont think so... whats the difference, where's the other one?

-Another post mentioned the ECT sensor? whats that?

I'd like to remind you i dont have no CEL.

Nightmare goes on, me? waiting for replys from you guys, thanks!

 

Did you ever check to see if you can get a CEL? I think that this would only take a second to test and may help find this ghost of a problem.

The ECT is the engine coolant sensor. It tells the ECU when the coolant is up to operating temperature.

I have a question that I don't think that anyone has asked you yet: Do you have a Helms shop manual? If not I strongly urge you to purchase one. You can order one here: http://www.helminc.com/helm/search_service...TJ8W3UABAH1A0D9

Hope this helps,
Bob

 

What or who gave you the idea to change all of these parts??? There are ways to test parts to see if they are functioning properly instead of replacing them.

Catalytic converter $$$

 

Doest the S2K have a wideband O2 sensor?

If not then it should go into open loop when the throttle opens past a preset amount or else WOT or heavy load af ratios will be too lean.

 

I didnt actually pay for these parts, they were all transfered from a fully functioning s2k. Including the stock exhaust.

What else do you guys think about that?