2001 150 hpdi stalls

[scotakns]

I have a motor that is stalling very badly. It has new filters, new fuel, it has over 50 psi at the vst when problem occurs. I also took the hp pump apart this morning and found one screen and removed it for inspection and it was perfectly clean. Is there a chance that there is another screen in there that could be clogged. Every once in a while it acts like it is going to run right, gets up to about 4000 rpms for a few seconds and will then stall back out. This morning I also unplugged the o2 for a minute and after I plugged it back up it ran good again for a short distance. I am a Master Honda Tech and would like to figure this out if all possible, but I know without the proper diagnostic equipment I may not be able to. I have been reading some of the post on here and it seems there is some great info to be found here. Thanks in advance for any help!
Scott

 

[scotakns]

Re: 2001 150 hpdi stalls

Rodbolt,
I need your help sir!

 

[scotakns]

Re: 2001 150 hpdi stalls

To check the high pressure, do I back probe the pink and blk wire and it should be around 3 volts between the two wires?

 

[rodbolt]

Re: 2001 150 hpdi stalls

yes, pink to black,2.8 to 3.2V at all RPM.

 

[scotakns]

Re: 2001 150 hpdi stalls

I checked and I have around 3 volts at idle. Should that mean that the hp pump is in good working order?

 

[rodbolt]

Re: 2001 150 hpdi stalls

only means that at an idle with no load its working, fine if all you ever wish to do is idle with no load. thats why you MUST monitor BOTH medium and High pressure rails AT the PROBLEM RPM AND LOAD.note the emphasis.
the only time the ECU will react to the O2 sensor for fuel correction is below 1500 RPM.

 

[scotakns]

Re: 2001 150 hpdi stalls

I gotcha!
I am going to load test it and see if the pressure reamains the same. I do know that the vst pressure stays above 50 psi when it happens. I just wanted to make sure I was testing it right. I know better than to question your knowledge sir
If anyone ever needs help with their Honda Automobile, please feel free to contact me.
Scott

 

[scotakns]

Re: 2001 150 hpdi stalls

Now I am even more unsure of what is going on. We put new spark plugs in it and went to the lake and it ran great 5500 rpm's for a mile or so , and then all of a sudden it would start dropping rpm's and would stall. I could restart it and it runs good again for a while. I was not able to check the voltage on the hp pump while running accross the lake. We are planning to take it to Rockwall Marine on wed. and see what they find. He has a master Yamaha tech working there. To me its almost like it is picking up bad fuel when it stalls, but that doesn't explain the restarting and running good senario.

 

[scotakns]

Re: 2001 150 hpdi stalls

What would happen if #25 was removed and a straight pipe fitting was installed instead, This is how mine is right now.
http://www.boats.net/parts/search/Yamaha/Outboard/2001/VZ150TLRZ/FUEL 1/parts.html

 

[scotakns]

Re: 2001 150 hpdi stalls

Just a thought, but what about the filter that is in the fuel pressure regulator?

 

[scotakns]

Re: 2001 150 hpdi stalls

Anyone know about #25 part??

 

[scotakns]

Re: 2001 150 hpdi stalls

I pulled the fuel pressure regulator off and the filter in there had some film on it. Also found that the regulator would not let any air pressure bypass through it. I used a small pick and pushed it up from inside and and it acted as though it was stuck, after that I was able to get some air flow through it on the fuel pressure side. The dealer did say that the vst pressure was high. I will let everyone know how it runs later.

 

[scotakns]

Re: 2001 150 hpdi stalls

I also just got the invoice from the dealer who worked on it and it shows it had a code 16 plugged injector or fuel filter.

 

[badhabits49]

Re: 2001 150 hpdi stalls

Have a 2001 150 hpdi bought new and had the same problem while under warranty and Yamaha spent over $2000 on it changing parts and I finally got them to change the throttle position sensor and it fixed the problem, even though the factory tech said it would not fix the problem. The TPS is the cheapest sensor on the hpdi, go figure. This was in 2003 and have not had a problem since.

 

[rodbolt]

Re: 2001 150 hpdi stalls

no codes for plugged injectors.code 16 was ONLY used on the carburated 3.1L V6 engines and then it indicated a trim sensor fault.
if an injector shows abnormal firing voltages it can set a code 26, a code 25 would indicate low hp fuel rail pressure.
the TPS is just to simple and easy to monitor.
if you suspect an intermittant failure then either use the laptops data record function to look at the last 13 min of engine operation or use an analog meter and monitor it real time.
NO air is supposed to move through the regulator.
O2 sensor wont affect the engine after about 1500 RPM.
the Z motors only used the O2 sensor for fuel corrections below about 1500 RPM.
thats the nice thing about being able to record the last 13 min of engine run time, you can go back and watch what is happening to various engine paremeters while it happened.
if the VST regulator filter cloggs you will see an increase in medium pressure rail pressures.
wont matter much as that pressure is gonna get stepped up to about 625 PSI anyway.
removing or gutting part #25 in your reference is a GOOD thing.

 

[badhabits49]

Re: 2001 150 hpdi stalls

The TPS never did set a code and that was why the Yamaha techs did not want to change it, was set correctly and would check good with engine running, local mechanic even rode in the boat with computer hooked up and could not get any fault codes, but when it was changed never had the problem again.
Badhabits49

 

[rodbolt]

Re: 2001 150 hpdi stalls

badhabits
they got lucky or lied.
I suspect lied.
however the TPS can fail in range and the ECU not throw a code.
thats the difference between a tech and a guy with a laptop chunking parts.
like I say, the TPS can be monitored with a simple voltmeter.
on a Z motor, as long as the TPS feed back to the ECU is between about .45V to about 5 volts its happy and WILL NOT throw a code.
once the code is set and active it troubleshoots itself.
with code 18(TPS) active ign timing defaults to 7* BTDC, idle speed is increased to about 1100 top speed CANNOT be reached and fuel is fixed.
its pretty simple.
almost any sensor failure will result in fixed low speed timing and 1100 RPM idle, however depending on the sensor top speed may be attainable.
just not a TPS failure.