Hi, my accord has had this problem for a while, only happens on motorway journeys, usually 15 minutes into it. Idle is fine, power is ok, no misfiring, no other codes. I changed the plugs, cleaned the air filter. I can't find a MAF by the air filter (there is another sensor along the air duct, [2nd pix] I don't know if that's the MAF, but I can't get it out). Any help, greatly appreciated. Thanks

this is by the air filter. No wires

this sensor further away from the air filter

 

I had to look back at an old post to figure out your car. You have the equivalent to and 04-07 Acura TSX.

P0171 means the engine computer is detecting too much oxygen from the O2 sensors in the exahaust and the adjustment to add more fuel reached a limit. There are several items that can cause the O2 sensors to see too much oxygen, so you'll have to start eliminating items.

Your car doesn't have a MAF sensor. That sensor you found is the intake air temp sensor. That hose connection is a vacuum line and I can't remember what it does.

If your scanner used to read codes can read live data, take a look at the short and long term fuel trims when the engine is warmed up. Let us know the approx short and long term fuel trim at idle and at about 2000 rpm.

 

Hi, I just run the tests. Whilst I don't understand the data itself, I have noticed an error propping up every so often (possibly a lambda causing an open loop, Perhaps a false contact?) Please see the pics and movies. Thanks for your help.

idle speed Closed loop - using all oxygen sensors

I got this msg as I accellerated


Back to Idle - Open loop

 

For the error message, what kind of scanner are you using? This is to google search that scanner code to maybe get a hint.

Forgot to ask this earlier, but was any work done on the car or any other issues (like filling up with gas, accident, etc) before you started getting the check engine light?

From the data, the fuel trims are definitely showing a lean condition. The change in rpm doesn't affect the fuel trim, so a vacuum leak becomes less likely. You'll need to do some more scanning to get some direction.

For the plots, can you switch the scale on the map to mm Hg? It is a more useful unit when measuring vacuum pressure. Can you also plot the bank 1 sensor 1 equivalence ratio, intake air temp, and the battery voltage? You can remove the fuel trims if you can only plot 4 at a time.

 

Hi, I was using EOBD-FACILE. I also got a VCDS light, for my VW, I don't know if it will access the Honda. I'll try tomorrow.
No accidents, Today took the car out on motorway trip, 120 miles, without problems. mhmmm??
I don't know how to access the Honda on VCDS, It only gives me access to a very short list of cars VW, Audi, Seat.