2001 150 HPDI Problem

[gearhead74]

Hello, can anyone help me with this issue? I have been working on this motor for a while and can't see any obvious problems. The guy brings me this boat with a 2001 150 HPDI. The boat has been sitting for 3 years with fuel in it. I pumped all the fuel out and replaced the fuel line and primer bulb before trying to start it. I also drained the VST. The motor would not start or even try. I checked for voltage at the mid pressure pump and it was good but the pump wasn't running so I pulled the pump out and replaced it with a new Yamaha pump. Now I have 50 PSI ant the test port and the motor starts and runs great until you get up to about 2500 RPM in the water then it starts to miss and sputter like it is starving for fuel. You can only get 3500 RPM's at most. I replaced the mid pressure filter and the screen on the mid pump, I took the high pessure pump off and went through it and found it to be very clean. I re installed the pump and put it back in the water only to have the same issue. Can anybody tell me what else to look for that would cause this problem? Thanks a bunch.

[Sparkieboat]

I am not real familiar with HPDI motors but I would assume they have some type of injector like my 4 stroke...you probably have clogged injectors, send them off for cleaning and flow testing/pattern test. other than that maybe a sensor or something.

[99yam40]

HPDI stands for high pressure direct injection.
You need to be monitoring the high pressure side as well as the medium pressure while the problem occurs. If one or both drops out of spec then you will know where the restriction is located. If pressures stay in spec then do like Sparkie said and pull and have the injectors tested and cleaned.

[boats.net]

Needs to connected to computer diagnostic to see if high pressure pump is at 750 PSI or more.

[Inducted]

Don't forget your high pressure fuel filter. I think it is #20. 2001 Z150TLRZ Yamaha Outboard VAPOR SEPARATOR 1 Diagram and Parts

[gearhead74]

150 hpdi

I replaced the high pressure filter today and went to the water only to have the same results. I have a feeling it is going into RPM reduction mode for some reason. I also checked the two lift pumps for pressure and vacuum and they checked out okay as well. I am stumped without having the software and patch cable to run diagnostics. I sent the guy down to the Yamaha dealer to have the ECU scanned so when I here back I will post what they found. Thanks for the replies guys.

[99yam40]

Did you monitor the pressure and vacuum while the problem was occurring?
May read ok at lower RPM but not at higher.

It would be great if you did post what was found

[gearhead74]

No, it would be too hard for me to monitor the vacuum and pressure while running the boat by myself, I would probably kill myself LOL. The boat is now at the dealer to see if any codes are in the ECU and to have the high pressure pump tested for correct operating PSI. Hopefully they find something I have missed. I will inform you guys as soon as I hear from them. Thanks

[99yam40]

Hopefully they will give it a test run on the water or put a test prop on it and run in their tank. There is the need to test pressures while problem is occurring.

[gearhead74]

I heard back from the stealer I mean dealer today and they said that the high pressure pump is only putting out 50 PSI at the fuel rail and that it needs to be replaced or rebuilt. I have a feeling when I get the pump back I will have the same problem. I will keep you guys posted. Thanks

[99yam40]

Do you know if that 50# came from the computer read out for the high pressure side while at the problem RPM or just idling?

Hard to believe that it would be at idle, as it should be up in the 750lb or above range. Seems it would not run with that low of pressure on rail, and you said you saw 50 on the low pressure into the VST.
Maybe the 50 was what it dropped to when problem was occurring.
Normally the pump runs or it does not, never heard of it running slowly. Could be the screen into the pump is plugged, or maybe there are screens internal that are plugging.

It would be good to hear exactly what RPM that pressure was taken at and the rest of the test data

[astrobud311]

Does that motor have the cheap little basket filters. I figured it would since I believe all or most of the hpdi's have them. I had an RPM issue on my port motor. Wouldn't go above 3600 RPM at WOT. I replaced the VST filter, HP fuel filter and those little bastard basket filters. Can't say that this is your problem but there real cheap and pretty easy to change out.

[gearhead74]

99yam40---The guy told me that the pressure was read at the fuel rail while the engine was idling. So basically the high pressure pump is not boosting the pressure at all. But it will run on just 50 PSI you just won't get much out of it. astrobud311---Here is a link to a parts diagram can you tell me if you are talking about part # 15 ? It is a small screen and I have not checked that. I think we may be on to something. Let me know what you think. Thanks guys. 2001 VZ150TLRZ Yamaha Outboard VAPOR SEPARATOR 1 Diagram and Parts

[99yam40]

I replaced the mid pressure filter and the screen on the mid pump, I took the high pessure pump off and went through it and found it to be very clean.

Does this mean you replaced #20 and #28 already or at least checked and cleaned?
#15 is on the pressure regulator and if that was plugged I would think the vst pressure would be out of spec. or is that on the rail and regulates the high pressure?
I really do not know.

[gearhead74]

Yes, I replaced #20 and #28 and the electric pump. I wonder if that little screen #15 could be clogged and maybe that regulates the high pressure. I will have the boat back here on Monday and will go back through the VST and the high pressure pump looking closer for any screens that may be clogged. I will keep you posted. Thanks