BF175 Alarm

One of a pair of 2007 BF175's. Will run all day just fine, but if you up anchor after a stop and then bring it up on to the plane at the normal rate it will alarm and go into safe mode. Restart it and the problem goes away if you then ease it up onto the plane at a slower rate. It will also alarm if you go WOT for a couple of minutes.

So far - has a new O2 sensor as initial fault codes suggested this according to the mechanic. This did get rid of a previous alarm that occurred at low rpm's, but didn't fix the WOT alarm. Don't run WOT so that wasn't a major issue. The getting on the plane alarm is a new one and is an issue.
Have pulled and checked thermostats plus shot the head temps (at the dock) whilst running. All 4 heads on both engines show similar temps.
Checked for water in the filters
Checked alternator voltages

Just now I jumpered the connector for the fault codes and got a steady on MIL light (no blinks) even though this problem happened multiple times over the weekend trip.

Anyone seen similar before or have some inspirational ideas?

Was wondering if the HP fuel filter might cause this but according to the mechanic's invoicing this was changed not that long ago.

Any ideas why I can't pull fault codes after the engine was entering 'safe mode' a day ago?

All input appreciated.

An actual overheat will sound alarm and put you in SAFE mode but I don't think it will throw a code off the ECU. When is the last time your water pump impeller was changed? Thermostats checked?

which light is on, when alarming ? Or just check if oil light (green ) goes off ?

continues alarm or intermediate alarm ?

indicator lights are more important

wajira

Hi Aliboy,

I have a couple of ideas...none of which it probably is....but...you said.....all ideas....so.....here goes:

Alternator "ripple". Alternators produce alternating current that is rectified to become direct current to charge the battery. If any of the rectification diodes begin to fail or the interconnecting wiring to them becomes compromised, a bit.....or, possibly, a lot....of ac current can enter your engine's electrical system. This ac volts leakage, or "ripple" as it is widely referred to, can cause all sorts of issues because it can upset the ECM's ability to interpret incoming sensor information. GIGO...Garbage In Garbage Out.

But. it's really easy to check for. Simply put your multimeter on the AC MILLIVOLT scale and measure your voltage across the battery while the engine is running. There is usually never 0 volts ac but typically you might see 0.006 to 0.015 mv ac at idle. If you increase engine speed you may see that reading rise. But in no case should you read anything in excess of 0.050 mv ac.

Another thing that can cause a similar reaction in the ECM is a bad ignition coil. Those COP (coil over plug) coils are high energy coils and, as they begin "break down" they can throw off some pretty wild voltage spikes. This so called EMF (electro-motive frequency) or RFI (radio frequency interference)...and other names....can cause havoc with the ECM doing it's job.

Unlike the simple ripple test...coils are a bit harder to ferret out even when equipped with sophisticated test equipment like a high speed graphing meter or a lab scope. Sometimes it comes down to swapping the coils from the offending engine to the good runner to see if the problem follows the coils or stays with the engine.

And, one last....and pretty off the wall.... idea I had would be possibly something going on with the knock sensor. I pulled up the parts page that your knock sensor is on and something caught my eye. Your engine block has a few anodes spaced around it. But two in particular made me think twice. Refer to item # 4 on the page link below and you will see that there are two of them. The way they are held in place makes me wonder "what if they were to be deteriorated and start rattling around under that "sealing bolt" (item #6)? That COULD set up some noise the knock sensor might pick up and cause it to drastically retard the ignition timing during high engine load events such as trying to get up on plane. Or, the knock sensor itself could be going south. Here again is an area where testing might consist of simply swapping it to the other outboard to see if the symptom follows. I don't know....it's just an idea.


http://www.boats.net/parts/search/H...d Later/BF175AK2 XA/CYLINDER BLOCK/parts.html

Other things to consider that might not set a code would be crankshaft sensor or loose or faulty wiring going to any number of sensors (oil pressure, engine temp etc...) that might go open or otherwise present the ECM with a "value" that would confuse it or put it in safe mode.

Maybe these ideas will give YOU some ideas of your own.

Good luck.

Thanks for all the tips guys. I am busy with other work today but will probably get back into this engine tomorrow. The problem only occurs when the engine is under maximum load (i.e. climbing onto the plane or at WOT).

Engine was serviced around 10 - 15 hours ago (maybe 1 to 2 months ago). Both impellers were pulled and checked. They were absolutely fine. Both thermostats were pulled and checked in hot water. They were also fine. Whilst it matches the symptoms of an overheat situation, the alarm when planing off can be after you start the engine from a 2 or 3 hour fish with the engine only luke warm at that stage. It seems to happen too fast for the engine to have truely overheated. We will go out and bring up the alarm and shoot some temps tomorrow to try and prove (or otherwise) the overheat situation. I haven't been onboard when this occurs yet so will monitor the lamp/alarm codes when we go out to get a bit more info. After that I will start working through the more obscure possibilities.
Does anyone know whether low fuel pressure will cause the engine to enter safe mode? Has anyone got a list of what will make the ECM go to safe mode?

the engine will go in to safe mode only at Over heat, low oil pressure and Over rev (rpm 6300 )....

Other sensors failure like TP sensor it will alarm intermediate and rpm will fluctuate also. at all the time it will give indicator light except water in fuel it will give only alarm but engine will not go to safe mode. Any fuel issue it will not go to safe mode


wajira

Did a little more testing on this yesterday. Left the marina and the alarm went off just as we started to throttle up. Red light at the dash and solid tone. We couldn't do any testing in this heavy traffic area so restarted the engine and went to a quieter area. Pulled the engine cover off and then tried to reproduce the alarm. Wouldn't go off again despite lots of WOT. start/stops etc. Checked the temps on both heads and port head was hotter than stbd one. Compared it to the Port engine and it was the same. Port side head hotter than stbd head, but pretty much the same numbers as on the stbd engine. Ran out of time so didn't get any further with it today. anyone got any ideas about why both engines might run a bit hotter on the port side of the block?
It really looks like we are getting an overheat alarm, but can't be sure from the testing so far whether it is a real or dummy one. Going to look at swapping temp senders between the engines and also have a look at the pressure relief valve to see if it could be sticking (once I find it on these engines).

When I installed external temp sensors on each bank of cylinders of my 225, I also noted that the port side got hotter than the starboard side. I switched sensors and gauges with same result. The checked with a good heat sensor. Same result. Asked dealer and folks on this forum. No one had a good answer. I speculate that it has to do with the amount of water being forced through each head by the water pump at speed. Both cylinder banks read the same temp at idle or when slow trolling. What I'm saying is that the differential in temperature may be a false lead.

Do you have a 4-light console? If so, what lights are on when fault occurs, and what type of alarm - continuous, long beeps, or short beeps?

Red Temp light at dash with continuous horn. Solid Mil light with no flashes when jumpered for the error code check. Got our Honda expert coming on Saturday for a bit more help in the diagnosis. At this stage I am ~70% convinced that it is false overheat situation, but I am still learning about these engines.

IF your green oil pressure light stays on, then you are probably correct.

aliboy,

It seems there are two relief valves...one port...one stbd....both are in recesses on the aft end of the mount case. See item #9 in the link below.


http://www.boats.net/parts/search/H...7 and Later/BF175AK2 LA/MOUNT CASE/parts.html

Good hunting.

Well we think we may have sorted it yesterday. Piece of gunk under the port side pressure relief valve. A pain in the ar$e to do whilst the boat is in the water, but pulled both sides and found a suspicious piece of 'something' just under the valve. It was mobile and could have been holding the valve open intermittently. Cleaned both valves (which otherwise looked fine) and sea-trialled with no alarms. Final proof will be in it's next big run next weekend, but feeling pretty positive that it is sorted now. Thanks everyone for their advice and help. Now just need to sort out the BF50 on one of our other boats that won't turn over. Pretty sure that one is just a bad battery cable, so hopefully a quick fix.

aliboy said:

Red Temp light at dash with continuous horn. Solid Mil light with no flashes when jumpered for the error code check. Got our Honda expert coming on Saturday for a bit more help in the diagnosis. At this stage I am ~70% convinced that it is false overheat situation, but I am still learning about these engines.

Click to expand...

Very happy to read that you found that restriction in your pressure relief valve as that would cause an overheat.

Would be very Dangerous to assume that an overheat sensor is false as the next 'alarm' might be the shriek of a seizing overheated piston. With all that ocean/lake water to circulate, a localized overheat can be hard to detect with a fingertip (or laser gun) test, but still be catastrophic if ignored.

Easy to remove (pink and black wire connector and one bolt on mine) and test. (might as well check thermostat at same time.) With more than one sensor, temporarily pull each ones pink connector (while buzzer is active) to determine which one to test.

Connect your volt-ohmmeter and suspend in a pan of water with a candy thermometer. There should be no continuity until temperature passes (188f on mine, but check your SM for yours) and then as it cools below 150f the circuit opens again. This should be easier and more accurate than swapping sensors with other engine.

Glad you've found the problem, but I had to post this as I've seen so many recommendations to assume faulty sensors and assume no overheat based on local spot checks, just too risky and expensive to ignore and/or buy unneeded sensors.
Art

I agree. We were treating each alarm as a true alarm and shutting down the engine etc. The key problem was the highly intermittent nature of the damn thing. Why go off on a luke warm engine when you try to climb onto the plane? I am wondering whether the lack of water due to the stuck valve cause lower flow up around the sensor and hence a localised overheat. It is extremely unlikely that there was enough time under power for the engine to get into a more general overheat. The other funny thing is that I assume the valve comes open at high rpms's, yet we were getting an alarm at WOT which seems to have been because the valve was stuck partly open? Not 100% sure that we have this fully sorted yet, but fingers crossed.

Sorted the non-starting BF50 as well now. The main earth feed had cracked at the point where it enters the engine and the wire inside had rotted out. Had been intermittently playing up for a while, but was really inconsistent for some reason. Probably was changing depending on the tilt and steering angle on the engine when you tried to start it as these would have affected the damaged area of wire. Had previously checked every bit of the main cables except for this bit hidden in the rubber grommet. Only found it by feeling around for a hot spot when the engine was rolling over so slowly. Can love our Hondas again now

alliboy,

Learning how to use the voltage "drop" method for checking large cables in automotive (12v.) wiring systems would have kept you from "feeling around" for the break. Even if the cable were tested when the engine was in "just the right" tilt or angle for it to crank, the voltmeter would have pointed out that there was a fault present and would have eventually pinpointed that area of the cable for you.

Google volt drop testing and try it. I bet you won't go back to "feeling" again.

Well, went out to swing the compass yesterday morning and the damn overtemp alarm went off as I climbed onto the plane for the first time. Didn't happen again after I turned the engine off and on. Swapped the temp senders between the engines this afternoon to see if the problem follows the sender units. Boat is out again tomorrow so will know more by the end of Saturday.

Went out yesterday after swapping the temp senders between the 2 engines (4 senders) and after idling out of the marina the alarm went off when I got up o around 2300rpm. Almost impossible to have been a true overheat. Turned the engine on and off at that point to reset the alarm and it never went off again despite 3 more stop and starts at varying fishing spots. It seems that the alarm only activates when you are transitioning the engine from cold to hot. Once it is warm you won't see it again.

So far we have
Checked water pump
Checked pressure relief valves
Checked thermostats
Swapped Temp Senders
Checked voltages
Checked for blink codes (none)

Looking for ideas now. Next things I can think of would be to swap ECU's and run the engine without thermostats (just for testing).

Anyone got any other clever ideas or comments about swapping ECU's between engines and test running without thermostats?

It is possible that one of the t-stats is just being slow to open, causing a temporary overheat. Stopping and re-starting engine could be allowing it to finish it's slow opening process. So, when you make your test with t-stats removed, and no alarm, that may verify that possibility. However, I would not make any long runs with the t-stats removed. Your engine will be running too cool and will allow some amount of fuel pass your rings and contaminate your oil.

I like chawk_man's idea. It makes a good deal of sense....as he always does. I think, if it were me, I would try that for sure.

But, if that doesn't pan out then I would start thinking again about pursuing possibilities of RFI or electronics. As I wrote in my first reply to you, the high energy coil packs on most late model engines can produce a good bit of RFI when they begin to fail. CLOSE inspection of a coil that is beginning to go bad sometimes reveals tiny cracks in the plastic housing. I would definitely test their resistance and look at them carefully. However, looking at them with a labscope and having "known good" firing patterns to compare them too is usually the way they are identified as being faulty. Something most of us can't do on our own. You are fortunate to be able to do some "SWAPNOSTICS" though so I would take advantage of that.

Also, I would definitely try running the engine with the knock sensor off to see if that makes any difference. The best way to do that is to simply unplug it. It will log a code but hopefully it won't set off any alarms. If that makes no difference then you can remove it from the engine, secure it with ties or wire, and leave it plugged in. If the problem goes away, then the sensor may still be faulty or..it is picking up a noise as I described in my first reply. Or the old swapnostics with the other one you have available is another way to go.

We are all pulling for you aliboy!

I can't wait to find out that you nailed it and what it turns out to be!

many good ideas. first of all just confirm the engine over heating or not,for that when the alarm comes on, bring engine to neutral(don't shut down ) open the top cover,touch the exhaust manifold and see is it really over heating or just an alarm.if it is over heating you cant touch it.

then go further. this engine have 3 temp sensors,two on the exhaust manifold 1 in the block(which we cant see from out) if it is really over heating,engine cooling system have some problem if not some electrical fault (faulty sensor,faulty ECU,wiring )


wajira

On the advice of Honda's head of servicing here in NZ we ran SaltAway through the engine a couple of days back. One of my staff took the boat out yesterday and there were no alarms. I don't actually believe that it is fixed just yet, but thought I would update the thread with progress to date for those that are interested. We are taking the boat for a long run to a currently hot fishing area on Tuesday so will see how we go and report back. Hopefully the report will be about limit bags of fish and no alarms.

Ahhhh, limit bags of fish!.....it's been soooo long!

Salt Away is a great idea, ideal if you can begin before problems show up.

I'm battling a high speed overheat on my other engine, mixed a barrel with two gallons and 20 gal water and ran three flushes to point of barrel getting hot.

10% ratio came from the OH DOT Study linked from Salt Away web site.

Didn't help the OH warning and pulling the head revealed a pile of pieces too large to pass into lower unit. Other than that, cooling passages were surprisingly clean. Placed some of the pieces into a white vinegar soak and it did not dissolve at all.

BTW my post on Chubbsdad's indicator voltage thread just got sent over to moderation, I had included links to boatinfo.no/lib/library (dot) html where they have the real Honda Factory Service Manuals to browse and print.
Art

Salt Away is the best, but best for prevention, not cure.

I'm having same OH at Speed issues with my other engine and after all the usual 'fixes' my last pass was a 10% (recommended by OH DOT Study from Salt Away's website) solution in a barrel. Ran it three times (days apart) at slowed idle (to control suds) long enough (30-45 minutes) each time to really heat up the water in the barrel (188f once).

Had no effect on OH Warnings and then pulling the head showed Salt Away had nicely cleaned inside of water jackets, but there was a pile of clumpy crud partially blocking water exit behind lowest portion of (three cylinder Yamaha 90) Head.

Salt Away will definitely become a regular part of my rinsing program after every use.
Art

Wow, that's interesting stuff Art!

Do you think, had you known then what you know now, you could have pushed the blockage out with some "pressurization flushing" and possibly cleared things out enough to avoid pulling the head?

Just curious as to your opinion.

No way to flush them (clumps) out. They also are impossible to dissolve in any solution safe to use inside an aluminum engine. Dark gray cinder-like appearance so may be Aluminum Oxide, however no corrosion signs seen.

17 years ago (Head replacement from corrosion pinhole) I had been liberal with CRC Instant Cold Galvanize Spray on clean internal water chambers, factory Zincs still look good so I am wondering if the 'cinders' are a (Zinc Oxide) result of my application. I'll still use it, just not so much
Art

I run saltaway through the complete cooling system on my diesels every season (or two). Set it up with a spare smallish bilge pump in a bucket of solution feeding the front of the intercooler and the output that goes to the exhaust elbow is redirected back into the bucket so the fluid just recirculates. Just leave it running for 4 or 5 hours at a time and do a couple of runs over a couple of days. Seems to extend the period between acid washes of the coolers by a factor of 2. If I did it every 6 months it may even put the need for acid washes out to 10 years or more.

jgmo said:

Ahhhh, limit bags of fish!.....it's been soooo long!

Click to expand...

The fishing locally has been ridiculously good for the past 2 months or so. More limit bags than not for those that know how/where to fish. Unfortunately the fish seem to be moving into their summer dispersal at the moment so it could be that the huge schools are going to get harder to find for a couple of months now. I do however have an excellent spy network and should at least head out with the hot spots from the previous day on my chart. Been living almost totally on fresh fish for the past 6 weeks or so. Had some roast beef for dinner last night as a change and now ready for more fish. With a bit of luck they will be parked just outside my marina entrance in a couple of weeks. Catching dinner for the next few months will then involve around $5 of gas and $5 of bait. In fact my son often catches dinner fishing of the back of my boat at the dock whilst I am working. He hooked a ~25lb Yellowtail Kingfish on a live bait the other day but too many piles and structures for that to turn out as more than a broken line. Was exciting for a few seconds though.

Well the mission was 50% successful. Left the dock at 6:30am and ran for an hour out to the reported hot spot. Slowed down to scan around with the FF and soon came across a couple of small 'haystacks' hard on the bottom. This is the classic schooling formation for the fish we were after. Dropped anchor and threw a couple of lines over whilst we sat down to a feed of pancakes and bacon I cooked up on the way out. Rods came in after breakfast with no bait so we got serious with the fishing. Started a slow pick on average sized fish until the charter skipper friend who had told me about the fish sign in this area the day before came past. Said he had left his cell phone in the car and asked what was happening. Told him it was OK but not great so he headed out wider. Just as he was leaving my companions rod went hard over and he hauled in a good fish. Then my rod went hard over, and it was all on. Couldn't call my friend back as he had no phone. By 9:15 we were down to our last couple of fish required and returning anything that wasn't seriously big to the water. By 10:00 we were done. Went in to a near by island and anchored out of the wind for more bacon and fish fillets in spicy crumbs and a cold beer. Sat there for an hour or so then shot around to a scallop spot that we think no one else knows about and dragged our limit of scallops. Home just after 1:00pm for a big filleting session and a clean up.
That was the 50% that went to plan. As for the alarm, it came on just as we left the marina in the morning and after a reset we didn't see it again until we powered up after one of our stops later in the day. I am almost certain that this is not a true overheat as in some circumstances it will come on at less than 2000rpm as you start to take off from a short idle (from a cold engine). Could we have an issue with water not getting properly up to one of the sender units? Why does it do this only when you start from cold. If you take off with an already warm engine it is fine. Can I swap ECU's between the engines to check if it is an ECU fault, or are they 'personalised' to an engine in some way? Already swapped the senders between engines so it isn't a sender.