- 2002 Accord EX with F23A1.
- Chipped and tuned P61 ECU (OBD1)
- Motor has about 67k miles on it, longblock was installed with all new parts about 25k miles ago by a Honda dealership.

The car was running great on a street tune before I parked it for a couple of weeks. Filled her up and parked her in the garage.

Had one CEL code at the time which was for the primary O2 sensor (had been bad for quite some time before ever converting to OBD1). I compared part numbers for Denso universal sensors between the primary and secondary sensors, cause the secondary was still installed. Same part number.

So last week when I returned home, I pulled the second sensor, and installed an O2 bung plug in its place. Installed that sensor into the O2 bung in the header just after the collectors merged, and wired it up to the primary O2's wiring. Cleared the CEL and no more codes.

Now to the problem. Ever since I started driving it again, (before and after my O2 mod) the car drives fine in town, keeping it under 3K, but at WOT above ~4200rpm the intake sounds like a banshee, and the car barely pulls. Seriously, we're talking the bark of a K20 swap, the bite of a 300k mile D15.

VTEC is engaging correctly (~2400rpm @ high load), and I'm not throwing any codes. It just sounds like my motor's gonna pop above 4500 @ WOT. I tried a basic tune up, checked the plugs, wires, oil change, and adjusted the valves. Checked for leaks around the block but none, only some oil residue around the VC gasket, and even replaced the gasket. Car runs super smooth at idle and part throttle up to around 4k. After that, it sounds like my intake swallowed a swapped civic with no exhaust.

Bad gas? Clogged cat? I don't know what's going on, and it'll be the 21st till I can get to my tuner to check things out on the electrical side. Any suggestions?



Modified by paradigm_shift at 10:30 AM 6/9/2008

 

Bump for some answers!

 

Anyone contribute? Changed out plugs, wires, and replaced a leaking radiator cap. Changed the oil and checked coolant levels, all good there. I've run through nearly two tanks with the car acting this way, so I can't imagine bad gas. Swapped in a couple OBD2 ECUs and the car behaves the same way.

 

REALLLY need some help here...

If I run the car with an OBD2 ECU, might I be able to find some kind of indicator to the problem if I check the codes and rule out the obvious ones from the swap?