TOPIC: Stubborn 2005 Honda Accord 2.4L

I've had the groove for over a few years now, with no results. But I must say it's not Ron's fault. We've been emailing back and forth all along to find the problem.

The PCV intake is plugged. I reset the ECU… twice. I removed, inspected, and reinstalled the Throttle Body twice. The second time, I helped the new gasket with a light coating of black silicone sealant for good measure. I even changed the air filter and spark plugs to high performance units.

But for whatever reason, there's never been any effect on my mileage. That Honda computer is very stubborn!!... I'm hoping someone in Gadgetman-land will have a bright idea…

And yes, I'm still smiling to strangers… Mario.

Thanks for bringing this one into the open, Mario. And for doing it so gently!

We'll get right to it. After reviewing the intake manifold diagram you so thoughtfully supplied, I went through it with a discerning eye and came up with this mark-up.

As you can see, I've isolated a few areas that would do with some further scrutiny.

Take a look guys and see what you think.

Ron

I have a 2007 Honda Element I am right there with you. I think the biggest difference between your motor (K24A4) and mine (K24A8) is that I have the electronic throttle body, not being an expert there could possible be other differences.

One thing I have been thinking of looking into to do some more research in the ECU effect on the groove is by investing in EMS, if I can find one that will work with that engine. Not sure when I will have the financial means in which to do it.

Best of luck to you and your car and please continue to keep us posted on any new findings.

Thanks
Shawn

Hi Shawn. Nice to see that I'm not alone with a stubborn Honda.

I did some more research. (Refer to the exploded view above.)
The intake on the EGR (item 2) is confirmed as the PCV port. It's plugged.
Item 3 is the power brake vacuum line (DO NOT REMOVE).
I just plugged the "intake air bypass thermal valve" (item 1), also known as the AAV (air assist valve). Seems we can live without it.

We'll see what happens…
Mario.

Guys check to see if the o2s are switching quick enough when they get lazy the ecu tries to compensate with you know what, gasoline!!!!!!!! dan gadgetman mo.

Can you guys check something?

Please see if these Hondas are using Frequency-Based MAP sensors and let's take a look at another direction for the reduced gains.

Ron

I am currently still evaluating information about Honda engines. So far here is a couple of quotes from hondata.com that might be of interest.

The first one, "The standard Honda MAP sensor can read boost up to 11 lbs."

The second one, "The stock O2 sensor is very inaccurate for anything other than 14.7:1 air fuel ratio."

So in answer to Ron's question I found a quote but do not remember where that made it sound as the major user of Frequency-based MAP sensors is Ford.

If the Honda ECU is handling data fast enough and appropriately handling it, I was ponder replacing the MAP and o2 sensors to see what would happen.

Id bet on the o2s how many miles on the engine? o2s do read different some read coarse fuel adj some read fine fuel adj. dan gadgetman mo.

As I mentioned before, I plugged the intake air bypass. After about 1/2 tank, it doesn’t seem to help.
If anything, the engine seems a little rough around the edges. So I'll just reconnect it.

I have an answer from my friendly Honda mechanic. The MAP sensor is a voltage type, not frequency.
It's beginning to make more sense that the MAP could be the main problem.
Whatever mod is done, if the MAP sensor always adjusts things back to "normal" pressures, we'll never get anywhere…

Mario.

I have got a fun one for you. After further research I have come to learn that the Honda Element likes to take electronics to the MAX. The engine has both a MAP and MAF sensor. Found them both on my car and on Honda's parts website.

Dan I have about 55,000 miles on the car at 5 years so they could be overdue. I know some of the OEM parts on the care are Denso (If that matters).

id swap o2s but since its yours you could try to relocate the map sensor and watch fuel trims when they go neg your on the right track. I dont reccomend messing with maf the map will make it thinks its in denver less air less fuel. good luck keep us posted.dan gadgetman mo.

I will probably look into replacing the o2. As of right now, I have no monitoring tools for my vehicle, although, I am planning on eventually investing in some. I also feel that another issue I may have without knowing the inner workings of the ECU is that the it is not letting the Air/Fuel Ratio out of a certain range despite other sensors and will continue to dump more fuel just to bring the ratio where it needs to be.

Another thing I did not think to mention till now, is that I had Ron's original groove and my gas millage went slightly down (in city) after the newest version of the groove was applied. So if the groove is more affective the car now needs to add more fuel to bring the ratio back to where it was before the mods.

Total loss ranged dramatically between 18 to 20. I think it is now hovering around 19 if in stop and go traffic all day. I truelly believe the ECU is confused and really has no clue how to react, based on different driving conditions I get each time or day I start my car.