I've had a momentary hesitaition problem just after startup on my 99 accord, 2.3 f23a1 manual trans. The problem has existed since i bought it. things replaced and hesitation/stumbling still exists: fuel tank, sock, fuel lines. also, technician ran scan tool and all sensors are operating to spec (as far as we know). The tech explanation is the computer is shutting down the fuel injectors or trying to shift into closed loop and cannot. I removed and opened up the ecu 37820-paa-L11 and tool these photos. does anyone have anything to add or can you tell me if everything "looks good" on this ecu? Also, what if any, ecu is compatible rather than the 37820-paa-408. can i use a 37820-paa-L61 ( which is meant for an auto)

p.s. the ecu does not smell, but the photos here show a slight rough texture with the appearance of tiny bubbles. sort of like it got hot? or is that how it is suppose to look. oh, and there are no vacuum leaks, the fuel pressure reg was checked, intake manifold rebuilt.

photos here:

37820-Paa-L11 Photos by Chrisgthemudlogger | Photobucket

 

I'll bite. First, read book shown. It was written before us Americans became idiots.

The bubbles on the ECU printed circuit board are from a protective coating called conformal coating. It's not a problem. You really can't tell if an ECU is "good" by looking at it.

Found a post that might be relevant:

98 Accord - Mother of All Chugging

 

Thanks For Nothing!! just kidding. I'm in the middle of War and Peace, so in ten years I'll check it out. seriously, the only other bit of data i found was the techician's scan tool would lose all data and act as if tool was first connected every time he turned the key off. He said this has never happened before to any other vehicle and that the scan tool would remember settings or input data as long as the tool was connected. So if true, the ecu isn't behaving as it should.

 

update: I replaced the ECU, programmed key at dealership and after $355.00 in labor and parts, the condition still exists. I know how to fix it now, just replace everything on the car.

 

Summer Time is here!! Temps are up. Guess what? Condition still exists.

 

There was a Honda TSB regarding the base idle causing hesitation during acceleration.

Honda TSB 99-064

 

Good TSB to read redbull-1..

 

Thanks for the input, however, symptoms cease after engine (snaps) out of it. The stumbling, loss of power, no reaction to accelerator pedal occur once in the first 5 minutes after startup, then not again as long as engine is running. I could drive it 5 hours and not a single mishap. i'm leaning towards O2 sensor, which as far as i know, should screw with things constantly. Or some EVAP control thats either letting in air or vapor at the wrong time or fresh air leak from somewhere.

 

Eureka! bought Denso O2 sensor (upstream) form Advance for $85 and another $35 for labor. Driven car three times and condition has not occured. Amazing (to me) that this stumbling, loss of all power would go away every time and not occur as long as engine stayed running. This problem has been ongoing for a 1.5 years and never has it gotten worse or better. Wouldn't you figure an O2 would get progressively worse?

 

more than likely a coincidence, i've never seen an O2 sensor cause a stumble condition. you'll be back when it comes back