BF225 O2 sensor buzzer

Here is my saga.

2003 BF225, 1100 hours, on a Pursuit 2200wa

History on the motor, the motor was originally hung on the transom in 2003, motor ran great for 7 years with engine oil/gear oil changes every 100 hours, water pumps every year and the fuel filters replaced every other year (never really needed it). Around 3 1/2 years ago, I had some issues with water in my fuel that was either bad ethanol fuel or a leaky fuel cap gasket or both. During this period I cleaned the injectors, replaced the HP fuel pump and filter, replaced the needle valve in the VST, the plugs were replaced, the 02 sensor was replaced, and cleaned/replaced the entire fuel system from the injectors to the fuel tank(3 times). I also had the tank and all fuel lines and fittings replaced, new 10m Racor installed, all the wiring replaced, the stern enclosed, and an Armstrong bracket installed. I battled water in my fuel for about six months before and after the tank was replaced. After the fuel problem was solved, or more like it just went away the boat ran better than it ever did with my highest top end 37 knots and better fuel burn numbers 12 gal/hr at cruise 4800RPM. The boat has run good for about two years with several 130+ mile offshore trips, with the motor running good at 5800wot and 16gal/hr. Then 5 months ago the buzzer, would fire off after the boat had run over 3000rpm and then run at idle speed, like when pulling into my slip. The engine was shut off and then restarted and the buzzer would go way for some time. This alarm did not seem to effect the motor as it ran fine. After a month or so of this the performance of the motor was slowly declining, so with some research I found out about the SB#56 and thought this to be my problem, so I purchased the kit and installed the new pipes and another O2 Sensor.

Photos attached of SB#56 tear down, this job took about 4 hours and was pretty straightforward.

After installing the new exhaust pipes per SB#56 the code was cleared and the motor was ran. The motor ran fine but the buzzer is still continuing to sound; I followed the troubleshooting in the Honda Service Manual and it still is kicking out the O2 sensor warning, next is to check the fuel pressure, if the fuel pressure is within specs(which I am sure it is) the only other thing is a short or open circuit or a bad ECM. Not sure how the motor could run fine for 10 hours run 130 miles if the ECM was bad? Any thoughts on this would be greatly appreciated. I should be checking the fuel pressure next weekend.

-Mike

WOW - four hours to change out the exhaust tubes. You must be one heck of a mechanic. Congrats on that!

But getting to the issue of the alarm - is your PGM FI ("check engine") light coming on? Is the green oil pressure light on? Any other lights coming on? Have you tried to pull any fault codes off the MIL by shorting the service connector? A faulty O2 sensor or faulty O2 wire will give you one blink on the MIL. Do a resistance test on the wire from the O2 sensor to the ECM. The manual gives you a pretty thorough check procedure - pages 5-26 and 5-27 in my manual.

If all that checks out and you are not getting any fault codes off the MIL, then you likely need to go on a hunt for loose or corroded electrical connection. Make sure the ground wire on the ECM is clean and shows little resistance between the ECM and battery ground.

That's what happens when you get lucky and don't break a bolt or strip a nut. I could have done it faster If I had help with the lower unit, that is a bear doing by yourself.

Yes I have checked the fault codes off the MIL and its the one long code code 10 (I think), this is saying its a bad 02. The check engine light comes on when the alarm sounds, but no other light is on or blinking. I will do the resistance test and start to test the connectors, I hate chasing electrical prooblems. Due to my previous fuel related problems I'm wondering if its fuel related? When the manual suggests checking the fuel pressure what is the likely culprit? Do I need to focus on the Low pressure side since this occurs at idle?

thanks

One long blink (2 seconds or more) is telling you there are no codes ( a code "10" is 10 short blinks.) Are you sure you are shorting the right leads? Reset the ECM per the manual. Then crank it up and run until the alarm sounds. Short the service connector and look for codes on the MIL. (I've forgotten which wires, but it is the two closest to the engine when the service connector is in it's holder - one is black and the other is green/white, I think - better yet, to make sure you are shorting the right wires, invest the $20 in the SCS service connector.)

BTW - I'm assuming that your green oil pressure light goes off after you initially turn on the key switch and before you crank the engine, then comes on and stays on when the engine starts up. Is that correct? (Just making sure there is not an oil pressure issue that is sounding the alarm.) I'm also assuming that your alternator light comes on and stays on until the engine starts up. Correct?

I went down to the boat and rechecked(I have the SCS connector), its one long blink, and according to my Honda manual that indicates a bad 02 sensor, a short/open circuit in 02 senor, bad connection from 02 sensor to ECM, or bad ECM. I also started the motor and neither the green light or the red came on at any time, not sure how they are supposed to operate, I can't remember the last time they were on?. I'm gonna have to pull the boat to check the fuel pressure and chase wiring but that is where i'm headed.

ps-The lights on the PGM/FI panel seems to be working properly.

Well, maybe we have a different understanding of a long blink and a short blink. But a short "1" blink will be about 1/2 second. If that is what you get, and it repeats about every 2 seconds, then your list of possible problems is correct. A long blink is about 1.5 seconds. And I believe that a single long blink, that is not repeated, means no codes, although that is not explicit in the manual.

Your problem and alarm could be oil level/pressure since the green light is not coming on. It should definitely come on once the engine is running. It's hard to see sometimes, so look carefully.

When you turn on the key you should get 2 beeps and all four lights will come on momentarily. Then the red overheat light, the green oil pressure light, and the red MIL light should go off. The red alternator light will stay on. When you start the engine, and if all is well, then the green oil light will come on, the red alternator light will go off, and the red overheat and MIL lights will stay off.

If that is not what you are getting, then we need to look in an entirely new direction, starting with checking oil level, oil pressure, your fuses, and your wiring harness.

Yes I guess I have a "1" short blink and it repeats. I'm pretty certain its a code"1"

I need to confirm the operation of the lights specifically the green oil pressure light. Not sure why that would kick out a code "1' though?

Went down to the boat last night around 9pm so it was dark enough for me to tell if the lights are on, neither the green oil pressure light or the red overheat light came on, not even at start-up. Got the beep and the batt and MIL lights came on but nothing out of the other two; I'm wondering if they are not hooked up? Will the engine run fine without them connected?

The engine will run fine without them connected, since they bypass the MIL. However, I would not do that. You really may have an oil pressure problem, and you will not be able to tell if you get into an overheat problem or not.

Sounds like you have something disconnected or corroded in the wiring (or two blown indicator lights.)

Right off the bat, I would do several two things...

1. Get to the back of the switch and make sure the connectors to those two indicator lights are connected and clean. And, I would test the bulbs - but not sure at what voltage. You'll need to track that down on the wiring diagram.

2. Check all your fuses.

3. Track down the oil pressure and overheat sensors and make sure they are hooked up with a good solid connection. The two EOP senders are deep inside on the block between the two cylinder banks. See the very last page of your shop manual and page 2-39. Pages 5-96 & 5-97 describe the testing procedure. Is it possible they were disconnected and not reconnected when you replaced your exhaust pipes? The overheat sensors are on the top of the exhaust water jackets.

Of course, none of this addresses your O2 sensor problem, if you really have one. As I said before you need to clear the codes from the EPROM and recheck your codes once you get the alarm again.

At this point I'm likely well beyond my level of competence. Would like to see Hondadude or one of the other Honda Techs jump in on these issues.

Tested the indicator lights and found them to be totally corroded, thought it was a sealed assembly but rust never sleeps.

I was able to get a used indicator light assembly from a local boat junk yard and installed and tested the motor. The green light came on and stayed on (think oil pressure is OK), but the red never came on, test this unit and found the red light to be inoperable as well. Got a new one on order 6-10 days $84 bucks for two little lights, jezz!

Checked the plugs from the O2 sensor to the ECM and found no corrosion or shorts or openings, two pins on the top most plug at the ECM showed very slight discoloration, I would not call it corrosion, but I cleaned them anyway. I'm not sure what else to check, the manual inidcated checking the fuel pressure, but the am unable to find a gauge that will fit.

Guess I'm taking it dealer, I'll let you know what I find.

Sorry we could not locate the problem. Let ius know what it turns out to be.

Talked to the service dept. today, should know something this afternoon. Can't wait to find out whatsup? Either way hope its not too expensive.

Rock N Robin - so what was the problem?

Also, are the Spanish still thick down off Virginia Beach? I'm thinking about trailering down your way for a couple of days of trolling.

Well just talked to the Repair shop (they did not call me as promised) and after much explanation they feel as though the O2 sensor that I replaced as part of the SB#56 was bad out of the box (they tested it and it was bad). So after much more discussion with a tense customer (since their parts department sold me the part) they will be installing a new O2 sensor and under warranty at that! I'm still not convinced this is the problem, as having a faulty NEW part is extremely rare. Anyway they are covering it under warranty can't ask much more than that; maybe that it wouldn’t blow the O2's to begin with?

Chawk- Yes they are here, all you want off Cape Henry stay deep and troll fast to stay away from the Bluefish; near shore and offshore have been real good as of late, fishing with a buddy (460 line, 40 fthms) we went 5 for 13 on White Marlin with 3 60 lbs YFT on Tuesday(best day of the summer!), 1 for 3 on Whites and 1 for 2 on Blues on Wed. and 0 for 2 on Whites with a nice Blue lost right at the boat on Sunday (030 line, 70 fthms). Not sure how this storm will affect the fishing this weekend? Thanks for the help on the motor, I fish outta Lynnhaven, I'm on Channel 68/79 mostly. Catchem up!

-Mike