F225 Digital code 28

[rpambrun]

My F225TXRC is running rough and like one cylinder is asleep, so after my copy of YDS V1.33 arrives and I get it installed on my netbook, I hook up the engine to see if it can tell me anything as to why it is running like it is. I had already cleaned the fuel, the tank and installed all new filters including in the VST.

I turn on the switch and find out that the number of motor hours is double what the seller told me and that there were some old codes that I deleted. I started up the engine to see if there was anything new and get a code 28 irregular signal from the shift position switch. I shut the motor off and go to do a injector test, but the YDS thinks that the engine is running or in Forward or Reverse. I can't run the tests until the code 28 is cleared, so I pull the injectors and get them ready to have cleaned.

I know there are several shift position switches. The one in the remote 704 works, so I am wondering what can I do to clear this code and what affect does it have on the engine running. I suspect it is the switch on the shift slider.

Any insight on how to clear this would be appreciated much.

[fairdeal]

interesting. I understand some of the theory, but have no experience in practice.
The neutral start switch at the helm has nothing to do with this - the engine ECU does not know that switch exists.

You have two microswitches at the engine shift linkage:



Now, it makes sense that you would have a running problem if the shift cut switch was in the "wrong state" (I would have to study whether that is open or closed)

But the neutral switch should only be noticeable >4500 rpms

And what is an "incorrect" signal anyway? (Code 28)
if its not really in gear, but the switch says it is - how would the ECU know that?
or vice versa?

[99yam40]

I believe if the ECU sees a start signal while not in neutral (or thinks it is not)the code will show

[rpambrun]

I believe that sooner or later, this code will be cleared, but in the mean time, I am wondering just what does it effect while the ecm sees this code. I am wondering if it has an effect on the current problem such as engine running rough like it was only operating on some of the cylinders.

Tomorrow, while I am waiting for my injectors to arrive in Naples, I will take a good close look at the switch on the shift slider and see if there are any loose wires or if the sensor is broken. I know the switch wiring harness was routed to be in the way of the shift slider until I found where it was supposed to be anchored. I'll check the connectors to see if there is anything wrong there.

Does anyone know what effect this has on the operation of the motor. What would the symptoms be other than the notification by the YDS?

Thanks

[rpambrun]

Here is an update. I replaced the switch causing the code 28. The old switch failed the continuity test. My injectors that I send to the Fuel Injector Man arrived and I put them in. I ran the LP and HP pump a couple of times to get the fuel rails full of gas and it started right up. But now the engine runs at a higher rpm as displayed on the attachment and it still runs as if one cylinder isn't firing. I shut it down and removed the plugs that I just put in last week and they were totally full of carbon. And instead of the code 28 as before, there is now a code 23 (Intake Temp Sensor). I'll check next time I'm down at the boat to see if I may have unplugged it during the fuel injector project. I'm not exactly sure where to look, but I think it is the sensor located on the port silencer.

Meanwhile, since I had the plugs out, I did a compression test. I forgot to open the throttle during that, so I'm not sure of the accuracy, but the numbers were all over the place from 170 down to 140. I plan on doing a decarbonizing later today or tomorrow to see if I can get things cleaned up and since the plugs were new, it didn't take much to get them clean.

Losing a lot of fishing time is making me think about adding a shot of Jack to my beer to adjust my attitude.

Any ideas or help would be greatly appreciated.

[99yam40]

does anything on the read out look wrong to you?

a negative 22 deg F might be wrong
and your ECU is calling for the ISC valve to be at 100%

And I know nothing about these motors

[rpambrun]

The intake sensor, I believe is on the port silencer which I have not put back on, so it is disconnected at the moment.

I ran the static test on the ISC valve and there were no errors or codes thrown. Yes, 100% seems to be in error. I'm running a decarbonizing in the morning and I will also boot up the YDS notebook and se if anything is different. I'm also going to look for any disconnected vacuum lines and check the fuel rail pressure.

[fairdeal]

yes, intake temp is that sensor down at the bottom of the "airbox" that we always forget to reconnect

I would imagine telling the ECU that its 22 below 0 would skew the operating parameters...

the only thing that I notice is the oil pressure - oddly low -
but oil pressure wouldn't affect how it runs...

[99yam40]

If something was telling me it was -22 out I would think it was too dang cold to be running.

I am sure it would run very rich at that temp

[rpambrun]

I have learned one thing for sure and that is not to run the engine with the "airbox" off and expect normal operation. With "airbox" on and the sensor and tubes connected, everything runs normal. I really kicks up the time the injectors are firing at idle from about 2.9 ms to over 3 ms and the plugs get a heavy coat of carbon.

[rodbolt17]

as you learned if ANY sensor is unplugged base timing locks to 7*BTDC the engine idles about 1100 RPM and top speed may or may not be reached depending on the sensor.
the ISC is not monitored for faults.
the shift position tells the ECU if it is in gear or not.
the shift cut misfires the engine to allow the shift clutch to disengage a gear. allways remember the difference between a sensor and a switch.
doesn't matter the poor translation from Japanese.

[rpambrun]

I have been continuing to get this motor to be under new management and as I do, I have learned a few things as I have fussed over this project.

I have done most everything I can think of to bring this engine to be one I can trust and place some confidence in. The low oil pressure that showed on my last printout was the result of the "air box" not being installed and the intake temperature sensor not plugged in. The ECU construed this to mean that the intake air temperature was between minus 22 and minus 30 and so increased the injector time by a good amount of time and set the idle at over 800 RPMs. This resulted in excess gas going into the crankcase and diluting the oil and there fore the low pressure of around 40 PSI.

Changing the oil and filter brought the pressure back up to normal. But as I scratch my head wondering what else I can do since the motor is not perfectly still while running in idle. I was contemplating checking the timing manually even though this last printout said that the timing was TDC. I'm not sure what I can do if it isn't perfect since I believe the ECU controls the timing.

Does anyone have any thoughts on that? If only I could get the prop chatter to take a hike. It makes my wife nervous.

Thanks for all the help and comments.

[boscoe99]

Install any brand of propeller that is designed to mitigate/eliminate prop chatter/rattle. Make sure that the pitch of said propeller allows the motor to reach at or near 6000 RPM when the boat is loaded, the throttle is wide open and the engine is trimmed only to the best speed angle.

[pstephens46]

Or just bump the throttle up 100 rpm when in gear.

[rpambrun]

I finally decided on a Solas Rubex prop 15 1/2 x 17P. It almost eliminated the shift clunk and it decreased the prop chatter a lot. At times, after running for a while, you can't even hear it. I'm getting 5800, but I have to admit that I have not had the best conditions for testing, so I am pretty sure that I can get to 6000, It not, my local prop guys can take it down and inch.

I usually idle in gear at 700 to 800 RPM anyway.