DF225 Running Rich and Making Oil

[Makeitdo22]

I'm going to break down and buy the 26/34 PIN TEST (09930-89340) to perform those voltages checks (the right tool for the job but $$$). It may take a few weeks go get here. The SDS will provide the timing advance and I should be able to do that once I get the boat back in the water.

I learned a lot about the White Wire power to the ECU with the forum info and by studying the wiring schematic. I found the WW bullet connector on the console side of the harness, and I am running a new WW directly from the battery to the harness at the console. Turns out I could go to the bullet connector on the engine side too (like it was currently). The main change that I am making is that the white wire will receive power directly from the positive terminal post on the main engine battery instead of the positive terminal post at the starter. No idea if this will make a difference, but it's worth giving it a shot to rule it out of the equation.

[redlowrey]

You don't need a test pin harness you only need a digital volt meter and check the voltage at the sensors, you have got no starting or running problems except running a bit richer than it should and it only requires a voltage drop test to various parts of the engine to see if you have voltage drop problems. You only have to look at your sds to see what voltages you have.

having the test kit for the 02 sensor, you connect every thing up and it will tell you what you already know, the engine is running a bit richer than it should be. The 02 sensor voltage will range between .1 lean, .9 rich, .5 stoitch or an air fuel ratio around 14.5 to 1. if the voltage was around .7 it would indicate there was too much fuel for the amount of air being delivered, but you cant flash it and change it.

I have not got a wiring schematic for your engine, if you have, look at it carefully, being a late engine I thought ignition supply came off the battery and the white supply from the starter fed the sixty and thirty amp fuses
You have not said that you tested the map sensor with a hand held vacuum pump very important sensor, that is the main sensor the computer uses for the amount of fuel being injected into the engine.
In my opinion the problem is external and the fuel in the crankcase is from too much fuel for a given throttle opening.

[Makeitdo22]

I'm tracking now. I'll put a meter on the voltage coming into the sensors to see what's coming in to them. I'll perform the MAP sensor test procedure in the manual as well. Just need to wait for a break in the weather and work to make it happen!

Thanks for explaining the O2 Sensor voltages. I'm still on a pause for performing the O2 Feedback procedure because I do not have all of the equipment and if I did have it, I don't know where to plug it into the engine. This is probably a good thing. I need to double check that there is not some other oddity causing the rich condition. But I really would like to have the nuclear option with the O2 Feedback Procedure ready. Trying to find information about the mysterious O2 Feedback Procedure seems like Suzuki's version of a snipe hunt!

[redlowrey]

Pull the fly wheel cover off and you will see the plug near one of the exhaust temp sensors.

[Makeitdo22]

Engine Top View 1.001.jpeg
Here is a top view picture of the engine. I added numbers and letters to form a grid to help define where it is located. Is it visible from this view?

[redlowrey]

Just below the oil filler cap , it looks like it has a silver cover over it, in between 5 and 6 and c and d.

[Makeitdo22]

Input voltage to the temp sensors is 4.74V both with and without the engine running.

Thanks for pointing out where the O2 sensor goes. The casting on this model doesn't have a plug/threads in the casting. Here is a zoomed in picture:
IMG_4342.jpg

Curious if there is an alternate location. If not, I guess Suzuki phased out the ability to perform the O2 Feedback Procedure. Any chance it could be this plug on the Starboard side? See arrow in picture below:
IMG_4343.jpg

[redlowrey]

You have one temp sensor and two exhaust temp sensors, I only need to know what the temp sensor is, if you don’t know check all three, they should be nearly the same as each other, only the iat sensor will have a different voltage.
DO NOT disconnect the sensors when you check the voltage, that would be the open circuit voltage with the connector disconnected.

Where I pointed out is where a df 300 ap goes. It has to be in the exhaust stream, pull it out and have a look, I am not familiar with your late engine.

[Makeitdo22]

I went ahead and picked up the 26/34 PIN to help with the troubleshooting.

I measured the cylinder temp sensor resistance as 2.3 k ohms when the engine was cold and the outside temp was 70F. The cylinder temp sensor voltage is 1.0V with the engine at idle, warm, with the 140F thermostats. The readings were very similar for the exhaust temp sensors, 1.1V, 2.24 & 2.30 k ohms.

I'll check the MAP sensor once my vacuum pump tool arrives.

Also, Voltage to ECM is 12.42 V. Sensor Voltage is 5.03V.

[Makeitdo22]

Update: After checking everything under the sun on the engine side (all sensors, fuel regulator, injectors, etc), I have found two things that were not satisfactory outside the engine. 1) The voltage drop on the cranking circuit was 0.63 on the positive side and 0.37V on the ground side; so a total of 1V drop. I read automotive mechanics say that anything over 0.3V on a single side could possibly cause issues on sensitive ECUs. I replaced the cables with thicker gauges (1AWG on Positive and 0/1 AWG on the ground which were the largest that I could manage through the rigging) and I reduced unneeded length where possible. I ended up with a 0.3V drop on the positive side and 0.15V drop on the ground side. 2) The second thing that I found was that my engine power circuit and house power circuits crossed at the gauges (fuel and voltage gauge were the main culprits). The ground was through the engine harness while the power was through the house circuit (or visa versa - I can't recall 100%). Specifically, this was an issue at the gauge lighting. So far I have operated for 2.5 hours, with these updates and the oil rise has seems to stop. I'll need more hours to fully verify. I can say that my fuel economy increased by about 10% at cruise. Though it still seems to run a little rich from the residue on the mid-section of the white engine. But this residue is less than what is was when I first recognized the problem.

So while I can't say with 100% confidence that this one is fully solved, I want to share my findings in case this helps someone else with a similar problem. I'll provide more info as I learn more.

[redlowrey]

Why didn't you come back with the results from the vacuum pump test with the map sensor, that is the sensor that tells the computer how much fuel to deliver for a given amount of air. There was nothing wrong with your original voltage drop test, sure you have improved it having cables and batteries that could start a 500 hp diesel engine.
If you wanted to do some voltage drop tests on supply and grounds do it on sensors that you think are failing with the engine running, then if you see a low supply or a high ground over 300mv then you will have something to chase. You didn't have a problem with the engine starting, or running, it ran great just delivered to much fuel.

Your problem was with the engine running not cranking, when there will be initially 200+ amps coming out of the battery, if you had a low supply or a high ground on a sensor, it would effect something in the system depending what it was.
.
Your problem could be as simple as the map sensor signal voltage being higher than what it should be telling the computer to keep the injectors on for longer, and being lower in signal voltage than the limit for a given throttle position signal to bring the check engine light on.