I have a problem I just caint solve. Please help me someone. I have the p0172 too rich on bank one code. If I clear it out it comes back in less than 10 miles. The car hesitates and possibly misses between 2200 and 2900rpms then clears up. It does it 10 times worse when it's cold but does it mildly all day long. This is what I've done. Changed out the throttle body along with tps and idle control, plugs,Coils,O2 sensor upstream, egr,fuel injectors and fuel rail, pvc, checked for vacuum leak, tested fuel pressure, engine coolant sensor #1. No change with all this done. Should I check vtech componets? Or evap componets? What about valve clearance? Or would the #2 coolant sensor in the radiator be doing this? I bought this car which had had an engine put in it with 50000 miles on it. They put a new cheap cat converter on it. Could that be it? What about the downstream o2? If I keep on putting new sensors on this car I'll go broke. Lol. They put an ecm or is it ecu in the car trying to solve this problem. The ecu is from a 05 accord ex with manual tranny. Mine is a lx with manual tranny. Would that matter?

 

Does your accord have a 4-cylinder or V6 engine?

 

It's the 2.4lt ivtech

 

Do you have a scanner that can read live data? Does hesitation/miss always happen between 2000-2900 rpm, or intermittently? Any performance issues at other rpms?

What work was done on your car before you started having this problem?

 

I bought the car like this so not real sure about any work being done on it. I do have a scanner and right now I'm might should be concerned about manifold pressure. It idles at about 4hg. It hesitates most when u open up the throttle underload. Going down road in 5th gear at 55mph and push it to the floor and it will jump and bogg down real bad. Let off the peddle alittle and it will clear up.

This is at idle

This is rolling down the road with alittle load uphill in 5th gear.

 

Get the engine to closed loop mode.

Plot the rpm, long term fuel trim, short term fuel trim, and intake air temp.

Do this at idle (~750 rpm) then do the same plot when holding the engine at 2000-2500 rpm while in park until the long and short term fuel trims stabilize.

 

OK. I will do that tomorrow. To mention the previous owner put a different ecu in this car so the Vin is different. The only thing I noticed is that it's an ex model and mine is an lx. Would that cause any problems and should I have the dealership upload the factory parameters? I put a vacuum gage on it today it held steady at 20hg with just a slight flicker of the needle but the map reading shows 5 to 7hg. So I switched out the map but got the same results.

 

Use a site like hondapartsnow.com to look up the PCM part number for your car and post the part number on the PCM currently installed on your car. All Honda PCM part numbers start with the number 37820. Can you find out the history on why the PCM was swapped and by who?

If the part numbers are different, I'd recommend installing the correct PCM for your car. At minimum, you want to make sure the EX PCM can properly run your engine. A replacement PCM would involve getting the keys programmed with the new PCM, so you can start your car.

You should also verify the engine wasn't swapped with an EX engine while investigating.

Be careful with the units, because 1 inHg = 25.4 mmHg. Double-check the scale you are using on your vacuum gauge.

 

The part numbers were the same for both Vins. The vacuum gage numbers that I gave u is 21 IN Hg. Or 52 cm hg. The previous owner said they ordered an engine from Japan. Some place that sold engines with low miles. It came in with 50000 miles. He showed me the receipt and it all looked legit. He installed a new fuel rail with new injectors. I even swapped out that setup with and 03 accord I have and seen no change. He put on an after market cat converter with new Delphi upstream o2. I have a steady 52lbs of fuel pressure. One thing is the fuel rail on this car and my 03 don't have fuel dampers and the manual shows that they both do. What is that all about? Is it somewhere else? The problem is steady getting worse as this car is my daily driver. Now it will just idle up to about 2000 for about 4 seconds during the high idle period of first starting car.
. Thanks for ure help and advise. I really appreciate this.

 

That is very strange that the PCM is reading 7.4 inches Hg while your vacuum gauge is reading a normal 21 in Hg engine vacuum.

What does the PCM read for vacuum when the engine is not running? It should be around 30 inHg.

See if your scanner can read the output for the MAP and also the MAF sensors.

Does your PCM have any other permanent or temporary codes stored?

EDIT: Are the wire colors yel/red grn/red, and grn/wht on the map sensor connector?