PLEASE HELP fellow v6 owners needs you.

[419superman]

Hi Guys, Having a weird problem with my accord v6 3.0

I have a highflow catalytic converter and decided to try and do the spark plug defouler mod to try and get rid of the CEL.

I tried this once 6 months ago, ended up frying the ECU because of not being careful with the 02 sensor when removing it. So i fixed everything, replaced ECU/ reprogram/new MAP sensor etc and dealt with the CEL

Well i didn't learn, and tried it again, sensor went in fine, with spacer, car ran fine for about 20 mins, then jerked really hard and stalled. I then pulled the battery cable, swapped in a brand new 02 sensor with no spacer, and still it jerks when im slowly accelerating, and completely shuts off (even radio turns off) then turns itself right back on.

The car drives fine as long as I accelerate very very slowly, once up to speed im fine, but then i get to a red light, and have to accelerate very slow again or ill stall and jerk.

Since then i have replaced the ECU and had it reprogrammed thinking that it was the same thing as 6 months ago, changed oil, and trans fluid. Nothing helps.

I keep getting the ECU code for the FTP sensor. But read this couldn't cause this symptom. Again, i cannot nail the gas/or even accelerate quickly at all without it completely dying.

Here's what i have considered went wrong, please tell me if i can rule these out:

Bad fuel pump/filter/FTP sensor (wouldnt i stutter at idle though?)
Cat is clogged? (bought 2 years ago, magnaflow)
Spark Plugs? (checked 3 of these, they look fine)
Main Relay?

 

[419superman]

bump please.

 

[001Stunna]

firstly, why are you bumping a thread only after a couple hours????

what is the actual code you;re getting?

 

[419superman]

P0453
and a P0420 (from my highflow cat)

 

[SykVSyx]

For your reference,

CEL Codes

 

[001Stunna]

P0453
and a P0420 (from my highflow cat)

P0420 indicates a bad converter or possibly a bad rear o2 sensor

Does the sensor show voltage when scanned? what voltage does it show?

P0453 is regarding high voltage in Fuel Tank Pressure sensor Circuit

If you've already changed the Fuel Tank Pressue sensor then you may have an open in the wire between the fuel tank pressure sensor and ECM

 

[419superman]

I haven't changed the FTP sensor yet.
A honda mechanic said this wouldn't cause stalling problems

And I haven't checked the 02 sensor voltage, because the light has been on for so long due to a high flow cat, so i figured the sensor should be fine.

Everything was fine until i put a spacer in the 02 sensor that was actually in the cat, not in the header. then i got the stalling problems.

So i bought a new sensor, took out the spacer, and hooked it up...still stalls.

I was thinking maybe fuel pump went out, or clogged cat.

But it only dies on acceleration, i can do 80 on the highway like nothing, vtec kicks in, but i HAVE TO accelerate very very very slowly.

 

[419superman]

thanks for the diagram, im a little confused.

I want to try monitoring the voltage to the FTP sensor, where are these terminals located? Are these the ones on the passenger side down by your feet that the ECU chords plug into? so i just touch the power wire of a volt meter to the terminal, and the ground to the chassis and watch the volts? aiming for 2.5

 

[001Stunna]

thanks for the diagram, im a little confused.

I want to try monitoring the voltage to the FTP sensor, where are these terminals located? Are these the ones on the passenger side down by your feet that the ECU chords plug into? so i just touch the power wire of a volt meter to the terminal, and the ground to the chassis and watch the volts? aiming for 2.5

The plugs are labeled in the pic i posted. One is the plugs of the ECU, one is the plug that goes in the FTP sensor.

It seems weird that spacing the o2 sensor out of the exhaust streams way would cause the issues you're having. Is your cat.converter bolted on? or welded?
If bolted on maybe try removing the cat.converter and see if it is fully gunked/clogged up.
To check the rear o2 sensor you need a scanner that offers live readings and graphing so you see the oscillations of the sensor voltage.

 

[419superman]

It's bolted on. Im thinking maybe if because i removed the 02 sensor is either heated the cat up to much, or clogged it.

I am going to pull it off, and put on the stock one.

That's the only thing that could possibly be related to the 02 sensor, because the sensors and ECU are both brand new.

I can imagine the fuel pump just HAPPENED to go 20 mins after i messed with the 02 sensors, its gotta be the CAT. or possibly EGR is dirty?