P0420 code 2001 honda Accord 2.4

I recently bought a 01 honda Accord with a p0420 code dianosed the cat will replace soon on the scan tool the rear 02 sensor is mirroring the front and I have a short term fuel trim of -22 the long term stays around -7 could a bad fuel pump cause this waiting on a fuel guage in the mail should I scope the injectors what way should I go isn't a negative fuel trim a rich command could the fuel pump cause this issue?

Hey chris! A fuel pump issue definitely could cause a rich condition, but I tend to think this is unlikely. Honda fuel pumps and regulators are usually very reliable, and rarely cause fuel pressure to be too high. That doesn't mean you shouldn't check the pressure with your gauge, but I'm guessing that you'll find all is well.

The MAP sensor is the primary fueling input on this engine, so that's where I'd suggest starting. The voltage reading at hot idle with no loads is what we're looking for. If all is well mechanically, at the correct idle speed, the reading should be around .9V. If it's around there, then we can focus on fuel delivery and the like. If it's too high, then we need to dig further into a mechanical issue. Make sense? Let me know what you find!

I can say from experience that these engines are very sensitive to valve adjustment and cam timing. Both have a big effect on intake vacuum, and therefore the MAP. If you do find high MAP voltage, then these are the two places I'd suggest checking first.

I hooked up my uscope and I had an amperage reading of 1.26 amps hooked in to the wire that runs to the fuel pump yellow and black wire after I check the map sensor should I go in the direction of fuel?

.9 is that almost one volt excuse my ignorance just wanting to make sure

Also ran an 02 test with my autel is said that the 02 sensor was out of spec so I know at least one of them is bad is my front O2 a afr sensor or a regular O2 sensor

With Key On Engine Off the MAP sensor should show atmospheric pressure for your height above sea level.

Thanks I'll check it out later on

chris.canty wrote: .9 is that almost one volt excuse my ignorance just wanting to make sure

No problem! .9V on the MAP is a good reading. That makes it easy to look away from valve adjustment and timing, and more towards the fuel system.

Also ran an 02 test with my autel is said that the 02 sensor was out of spec so I know at least one of them is bad is my front O2 a afr sensor or a regular O2 sensor

Really? :huh: What kind of data PIDs do you have available for the O2 sensor? I believe those engines came with either a conventional O2 or an A/F ratio sensor depending on what emissions level it has, so it's tough to say without more info. Alternately, you could look at the harness side wire colors for the O2, and I can match it up to the wiring diagram.

Speak of, are you sure this has the 2.4L engine? 'Cause according to my info, the Accord didn't start coming with the 2.4L until 2003. Not nitpicking, just want to be looking up the right info.

HERES THE VIN 1HGCG56671A102670 I did the test with the scan tool KEEO 2.85V KOER .92V DID A FUEL PUMP AMPERAGE TEST 5 AMPS WAS THE HIGHEST READING

You right it is a 2.3

Those O2 voltages sound good, consistent with a rich condition. Just to make sure the O2 can react, I'd suggest disconnecting an injector or two and looking for the O2 to show around 100mV. That would prove that it's capable of rich/lean switching. Your Koeo reading also confirms that this is a conventional O2, and not an A/F ratio sensor.

The fuel pump amperage sounds reasonable. I'd suggest a fuel pressure test next, and possibly an injector balance test.