2006 BF225 Check Engine Alarm Code 1

Yesterday had a alarming check engine light on the port engine. I was able to get the code #1 using chawkman paper clip on the red connector.

The 2006 engine (1400436) has the newer O2 sensor and exhaust tubes. O2 connector looks pristine. Check engine Light and alarm comes on occasionally and only at idle. performance at higher
speeds is good although port engine produces 200 rpm less than starboard at WOT.

Plugs, and all fuel filters, waterpump and stats changed in 2017. 150 Hrs ago. Port engine vibrates slightly more than the other at idle but no missing. Engine did stall twice going forward at idle 650 RPM but no alarm, first time engine ever stalled out on me.

Was thinking changing plugs first, then O2 sensor? Hope plug change in the water is not too difficult?

You may have one cylinder that is misfiring. .So plugs may be the answer.

Since it is in the water, start your engine and let it idle. Then momentarily disconnect each spark coil one at a time. Each time one is disconnected, the rpms should go down a little. When you connect it back up, the engine rpms should come back up to normal. If you get to a cylinder that there is no change, then that cylinder has an issue. If you have a new spark plug, change that plug and see if the engine runs smoother and the rpms drop when you disconnect the coil again.

It would be pretty difficult to change #6 plug in the water, since you have to partially remove the side cover.

Mike

Yes, I thought I would start with the plugs too. I would imagine an O2 sensor would throw the code more frequently or not just at idle. I changed the plugs myself in 2016, was not too difficult but it was out of the water and had the center cowling removed too for the HP fuel filter. Could not remember if the bottom plug needed the cowling removed too. Do you know if a authorized Honda dealer would be able to diagnose the exact problem with their scanner or would it just show code #1
Thanks. Bob

Yes, start with the plugs as Honddude recommended. A misfiring plug or coil will also throw a code "1". Check the plugs carefully. All plugs should have a milk chocolate color to them if all are firing correctly. If there is block soot on all of them, then it may be a failed HO2 sensor. If black soot on just one (or two) then possibly bad plug or coil.

Fuel pressure out of spec will also throw a code "1". So the next thing to check is the high pressure fuel filter. Those darn things will just deteriorate on their own. I now make it a point to change that filter every 100 hours. It will be difficult to do that on the water. I've seen some folks strap a dingy to the back of the boat to work on the engine, but that's problematic, to say the least.

If a new HP fuel filter doesn't fix the problem, then check the fuel pressure. There is a 6 mm bolt on the cover to that HP fuel filter - it's the fuel pressure relief bolt - that's where you check it. You'll need a fuel pressure gauge and a 6 mm adapter. At idle, fuel pressure should be between 42 and 49 PSI if my memory is still good. If fuel pressure is too high, then you will need to inspect and clean the fuel screens and filters down stream from the VST to the fuel rail. If fuel pressure is too low, then there is either a fuel restriction before the HP filter, or possibly a weak or failing LP fuel pump. If fuel pressure is too low, the first place to check is the large black grommet where the fuel line feeds into the engine. It often gets pinched or collapses in there.

Regardless, all of the above will necessitate that you pull the boat, IMO.

Thanks for the response and suggestions. I'm ordering 12 new plugs from boat.net today. I think I'll be able to peel enough of the mid cowling away to get to #6...I hope.
If that doesn't do it I'll have to get the mechanic at the marina to pull it and check out the rest.

Best way to peel back the cowling is to take out the bolt on the bottom (under the snap in cover) and the first four at the cowling split holding the top of the cowling. That will give you enough room.

I was thinking that may do the trick and I would only have to peel back the one side of the cowling to get to the bottom plug

I hope it 's just a plug I may order a spare coil with the plugs just in case

It's always good to have a known good coil around just to be able to test if you have a coil problem. However, I must say in 2100 hours over 10 years I have not had one go bad on my 225.

To answer your questions about the Honda Scanner....

It will identify the code and when it happened but will not indicate exactly why.

It will show other perimeters, like temperature, etc) of the engine that could cause the problem and he/she could do a cylinder drop test without disconnecting coils.

It will not show which cylinder (if any) are misfiring.

Mike

I'd just stick a new O2 sensor in while the boats on the water - if it doesn't fix it then at least he's got a known good spare and can then move ahead with the other tests that will probably involve the expense of pulling the boats from the water.
I'm going to be trying a $100 NGK O2 sensor soon even though I've got a new Honda one ready to fit.
Someone makes them for Honda and it may well be NGK.
Should be interesting.

I was considering swapping out the O2 sensor first, but I don't know what the replacement is on my 2006 engine. My mechanic says the O2 SB and exhaust tubes were replaced long ago. I looks like the O2 sensor is a tiny device half way up the original exhaust manifold, Is there a different O2 sensor after the SB or do I order the same part number shown for year and serial number on boats.net?

It depends on the frame serial number of your engine. Is that the number that you posted? It depends what SB that your mechanic did. Did your ECU get changed out, also? If you do not know, check the part number on the label on its side.

If you ECU was updated, then you only have to replace the O2 sensor.

I would still do a test that is free. Disconnect those coils. You do not have to take them out. Just pull off the connector going to each coil, one at a time.

Why change parts on a guess, if you can locate the source of the problem?

That can be done on the water at the dock in neutral....so it should be safe to do.

Mike

I believe the ECM were changed long ago probably when O2 and exhaust tubes.
Prior to 2011 since it does not show up in the Honda archives. How does one disconnect the plastic connector from the metal bracket? Can’t see it very well looking from the top. Thanks

Post your engine serial number and I can tell you what HO2 sensor and ECU you should have. It's covered in Honda Service Bulletin #70.

I'll try to attached that SB, but when I tried a while ago, it was too big. Will try again at the end of this message. If that doesn't work, send me an e-mail at [email protected] and I will e-mail the SB back to you.View attachment sb70 .pdf

OK. That worked. Open the .pdf file and it tells you what the upgrade part numbers are if your SN is in that range.

My 2007 (but apparently its a 2006 model) 225 has had the ECU and sensor update - in order to work with the updated sensor the ECU part number is 34750-ZY3-A04.
So if your ECU has that part number on the sticker then you want to order the later O2 sensor.

My engine serial number is 1400436 The Honda dealer said the ECU was most likely replaced prior to 2011 since the ECU hours are less than the tach hours.
Thanks for the help

Some hour meters run even when the engine is not running - mine included until I changed the wiring.

Thanks for all of your help with this. I ordered a replacement O2 sensor too. 5655-ZY3-C01 I must have the newer style the hex is smaller and not the 21mm. Should I use the paper clip and clear the code with the 5 On-OFF cycles before I replace the sensor to clear out the code?

Yes - clear codes. Then you will know any new codes are from your revised setup. Once you have successfully clear codes, you should get a double beep on the alarm.

maxthrottle said:

Thanks for the response and suggestions. I'm ordering 12 new plugs from boat.net today. I think I'll be able to peel enough of the mid cowling away to get to #6...I hope.
If that doesn't do it I'll have to get the mechanic at the marina to pull it and check out the rest.

Click to expand...

This is what I did to eliminate the PIA of having to remove bolts and pull cowling for clearance. I'm not faint hearted when it comes to cutting stuff so this maynot be for everyone. Coils get pulled and plugs changed with nothing more than the plug wrench and hex head for the coil removal now.

Problem solved!
Swapped out the O2 sensors and spark plugs and cleared codes with paper clip and ON-OFF 5X trick. I think it may have been the sensor all along, kinda black and sooty
but no corrosion, plugs looked good but swapped anyway. Engines put out same RPM at WOT now too. Thanks for all of the help here! Now to find an alternative to the
$200 "marine" sensor!

Unfortunately, I don't think there is a reliable substitute. Although this is essentially a Honda MDX J35A3 - A6 engine, the ECU's are different, thus the HO2 sensor is most likely different. However, that observation is not definitive - there may be a cheaper Honda alternative. But to find out, you would need to have access to Honda's proprietary electronics database, and that is a closely held trade secret. What I would not risk is trying an after-market HO2 sensor.

One could put a stand alone O2 sensor in the exhaust stream and read the fuel air ratio of the exhaust with both sensors and compare the readings between the sensors you are trying to interchange. Same ratio would mean interchangeable sensors. The ecu would have to be in closed loop for both tests to generate "apples to apples" results. Results would have to match for the entire rpm range.

I think that would be difficult. It's my understanding that the HO2 sensor operates between 0.1 and 0.5 volts and those voltages change very rapidly, depending on the amount of oxygen detected in the exhaust. Below is a link for testing auto HO2 sensors.

https://www.autozone.com/repairinfo...sHowTo&pageId= 0996b43f80a01215&subtitle=test

chawk_man said:

I think that would be difficult. It's my understanding that the HO2 sensor operates between 0.1 and 0.5 volts and those voltages change very rapidly, depending on the amount of oxygen detected in the exhaust. Below is a link for testing auto HO2 sensors.

https://www.autozone.com/repairinfo...sHowTo&pageId= 0996b43f80a01215&subtitle=test

Click to expand...

We'd need to figure out if the bf225s use a narrow band or wide band 02 sensor. The narrow bands have about a 1 volt range from lean to rich. The wide bands have a lot more range (~2.7ish volts). It wouldn't surprise me if Honda used wideband sensors based on the replacement costs of them.

I think the hard part would be to isolate a pure untainted exhaust stream to use for reading. Its not like these engines have tailpipes. LOL. Someone committed to finding a replacement could accomplish this. I've been using $50 Honda Civic fuel pumps in my outboards for years now. You'd be surprised at how many parts we needlessly over pay for because they are MARINE and automotive equivalents are readily available.