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Bullshipper, we know the culprits are cylinders 3 and 4. they start running rough at around 3,000 RPM. When we sprayed propane into them, they picked up around 400 RPM and smoothed out. The propane didn't affect the other four cylinders.
We are pretty sure the problem is in those middle two cylinders.
Sorry, I missed that. I was recanting, thinking it might be electrical, but your propane test is conclusive making fuel the problem, which we have thought now for quite a few pages.
When you say the boys syphoned out the gas from the tank, I am hoping it was using your fuel line taking most of the the crud from the bottom of the tank with it?
As for electrical problem issue...I fail to see how spraying propane into an air intake would affect an electrical problem.
Oh, I set up the siphon system for them. I used about 20 ft. of clear tubing I had, and yeah, I hooked it up directly to the barb on the fuel line right before it goes into the Racor. I didn't want all this running through the Racor. I started the siphon for them. Easy beans with clear tubing. All they really had to do was keep an eye on the gas cans to make sure they didn't overflow.
We saw chunks of stuff going through that fuel line. I told them they should filter the fuel, and they said yeah, yeah, and proceeded to fill their "new" Suzuki. I did notice they didn't pour the last gallon or so out of the jug, though. It had all the dirt in it. And there was a fair bit of dirt. Glops of snottly looking stuff, too. Strange.
Toward the end I was using a bottle jack and lumber to jack the front of the boat up so that everything in the tank ended up at the back of the tank. Saw the again today, a guy out with his girl, driving around in my old Suzuki. Big smile. Running fine.
As for electrical problem issue...I fail to see how spraying propane into an air intake would affect an electrical problem.
Oh, I set up the siphon system for them. I used about 20 ft. of clear tubing I had, and yeah, I hooked it up directly to the barb on the fuel line right before it goes into the Racor. I didn't want all this running through the Racor. I started the siphon for them. Easy beans with clear tubing. All they really had to do was keep an eye on the gas cans to make sure they didn't overflow.
We saw chunks of stuff going through that fuel line. I told them they should filter the fuel, and they said yeah, yeah, and proceeded to fill their "new" Suzuki. I did notice they didn't pour the last gallon or so out of the jug, though. It had all the dirt in it. And there was a fair bit of dirt. Glops of snottly looking stuff, too. Strange.
Toward the end I was using a bottle jack and lumber to jack the front of the boat up so that everything in the tank ended up at the back of the tank. Saw the again today, a guy out with his girl, driving around in my old Suzuki. Big smile. Running fine.
I'm talking electrical in the sense of the injectors firing not the spark plugs firing. It is just a thought. I agree It is a fuel issue I just think it has to do with the way it is delivered. Kind of like if an O-2 sensor says it is too rich it leans out the cylinder. If you spray fuel into a cylinder that is being starved for fuel because the O-2 sensor is saying it is leaning it out then it will run better. Again just my 2 cents.
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I still don't know much about how these things work. But I am not clear on how the ECM could lean out an individual cylinder. There are two fuel rails, each charged to 1000 psi by the belt driven HP pumps. Each rail supplies one side of the motor, i.e. a bank of three cylinders. The injectors are mounted with one end in the fuel rail, and the other end in the cylinder head. So, the ECM fires the solenoid/injector, and it opens and sprays fuel into the cylinder.
The only control I could see the ECM having at that point would be if it varied the length of time that the injector was open. And it might do that. I don't know. I haven't seen anything written about that yet.
Late yesterday I fabricated a couple crimp on connectors to put on the injector connector pins. Works just fine. I fired it using a 12 volt battery charger.
Hopefully today I can pick up some kind of carb cleaner or something, and the right size tubing to get from the air hose to the injector. I think it's worth another day or so delay to see if I can do something here to clean these out.
In my situation, even if I have to fabricate some kind of rig to get a job done, if it works it's good for me in the long run. If I can establish the capability to clean my own injectors, going forward it will be no big deal to pull them out and clean them. A morning's work. This is a good thing, here in the Tropical Land of MakeDoo... where the water is clear while the gasolines' cloudy....
Did I tell y'all we have signed up for big catamaran sailing certification courses? I sense sails and small diesels in my future....
Gringo some advice. You would do well to see my post re200 hpdi trouble. You have identical symptoms. The injector rails are fed from the top and during a low pressure scenario there is not a uniform pressure accross the rail hence some cylinders stronger than others. Remove and clean the filters in the high pressure pump and you will probably sort your problem as I did. This whole repair from start to finish took less time than you spend posting on this site each day so well worth it.If you need advice on this fix just ask.
I hope you get fixed and if I am wrong tell the world what a tool I am but dont knock it till you try it!
when you remove the cover and access item no. 21 it is in the main block behind it. Trust me its there.
For whatever reason, my engine seems to mirror the parts list, exactly. There is no screen in the parts diagram, nor is there one in the main block of the pump behind item 21. Just a small hole. I gently pushed a small wire into it, to see if it was way down inside that hole. nope
I just took the starboard pump apart, cause it was the easiest. It has it's own fuel feed, though, so if there were screens in there one would think there would be one in each side of the pump.
For whatever reason, my engine seems to mirror the parts list, exactly. There is no screen in the parts diagram, nor is there one in the main block of the pump behind item 21. Just a small hole. I gently pushed a small wire into it, to see if it was way down inside that hole. nope
I just took the starboard pump apart, cause it was the easiest. It has it's own fuel feed, though, so if there were screens in there one would think there would be one in each side of the pump.
Is the high pressure pump "two-stage" design. Being a pump that compresses fuel to 1000psi, I would believe it would be a two stage design. Possibly the port side is the first stage?
I am not 100% sure there is not a screen in there. It was late yesterday, and getting dark, and I wanted to get it back together cause I had other things to do today and didn't get back to it. I am going to have another, closer look.
Both sides of that pump get their own fuel feed. The fuel line splits before it gets to them. Each side feeds one rail. In looking over various tech bulletins, it looks like 800 psi is the magic number. Anything over that is good.
yeah, sorry. I been busier than a one armed paper hanger lately. Finally my son left, I got my new compressor and air lines installed and working, picked up a bunch of air tools, have been working on vehicles, sand blasting, spray painting, have had a lot of down time with the internet out lately etc. But back to the HPDI:
Here's where it stands. I located the filters that M680pjh has been talking about. Thanks, M680pjh! There are four of them in the HP pump block. And of course I took a series of photos of them, etc. if anyone is interested.
Here's the rear of it with all the covers and the pump covers removed. I found out that if you take them both off at the same time you can move the covers up over the motor and not have to disconnect any of the rubber fuel lines.
You do NOT want to disconnect the rubber fuel lines. Long story.
The little filters in question are cylindrical screens. There are two in each pump:
And they are little bitty suckers, man. I used M680pjh's method of just threading a screw into them to pull them out. It takes faith, because it just doesn't feel right. I threaded the screw in about four turns, and then used a screwdriver to pry under the screw head. Here's a photo of one of the screens, and the screw I used to remove them:
I found the penny, and decided to throw it in there for scale.
I did the old subjective put them to your lips and "blow through them and see how clear they are" tests. Highly scientific. Two of them, I could blow air through them fairly easily, and the other two I could definitely feel some restriction. So I soaked them in SeaFoam and acetone, and then blew them out with an air line. Then repeated the "blow" test. Wow, all four of them were suddenly a lot easier to force air through. It definitely made a difference.
I also removed the canister filter, the one in the line past the VST, and loaded that up with SeaFoam and let it set for a while. Then I hooked up the air line to it with about 100psi and blew that out, too. I reassembled everything, including the primary Yamaha filter that I had removed. It's not filtering much, but it does serve as a water trap.
Now, as for the injectors...I am still not a hundred percent sure that they are the problem. The reason is that it's just TOO strange that the middle two, on different fuel rails, and not the two that got wet, are the ones responding to the propane spray test. So, what I did was decide to see if I could make them misbehave in my shop. I made up some crimp-on connectors and hooked up wires to a push button, like others have suggested here. I used a small 12 vdc battery charger for power. When I push the button, there is a definite click from the injectors. So the solenoid works.
Then I filled the injector with SeaFoam and held the 100 psi air line to the top of it. I pushed the button repeatedly, and observed the fine mist that sprayed out of the injectors. I know it's not the same as having an $ 8,000 injector cleaning automatic sprayer, but at least it let me know that a.) all the injectors do in fact function and b.) the spray patterns looked identical, to the untrained eye.
I was clicking that button as fast as I could, until all the SeaFoam was blown out. La Gringa wandered in and took a short video of me doing it, and you can see the spray and hear it clearly in the video. I will probably put that up on the blog, if anyone is interested, in the next few days. Don't know how to post a video here. But here's a still:
I could only push the button to fire the injector about five or six times a second, max. I guess that corresponds to about 300 rpm, so it's doesnt really prove anything other than that my rig works, and the injectors work.
That's what the spray looks like at 100 psi. I can imagine what it looks like at 800 psi. But hey, I gotta work with what I got here.
Then I re-installed everything, injectors, fuel rails, covers, etc. yesterday. I put the former middle two injectors in the top two cylinders this time. So if they still misbehave, I can isolate it to those two injectors. We then got rained out. This morning I re-connected the fuel system on the boat, running both fuel lines from the tank pickups into the two "in" ports on the Racor. I cut out some of the old, original 1994 fuel line and did a little autopsy on it. Split it open lengthwise and scraped the inside, looking to see if anything would come off. Nope. Clean.
I bought one of those RACOR fuel funnels with a 27 micron screen in it, and have poured Texaco fuel from an automobile station though it into the tank. The motor is back together and ready to test again.
Right now, we are watching squalls blow through. But tomorrow and right through the weekend the forecast is beautiful. We will be taking the boat out to try it again as soon as we can. I suspect tomorrow morning.
I agree It is a fuel issue I just think it has to do with the way it is delivered. Kind of like if an O-2 sensor says it is too rich it leans out the cylinder. If you spray fuel into a cylinder that is being starved for fuel because the O-2 sensor is saying it is leaning it out then it will run better. Again just my 2 cents. 
or something 
