07 F90 low to now fuel pressure question

[rougeaut]

Hi I am just about there but still have no fuel delivery to the plugs?
2007 90 4 strk
I tested the high pressure pump out of the VST and reinstalled it and took off the output line to the fuel rail and it was a very strong fast flow, I also unbolted the fuel rail and turned on the key it blew off the injector from the rail but it was still connected by the electrical wiring so it did not go far but showed some pressure to the injector.
All of the plugs are dry and my question if the HP pump is working and the gas is in the rail to the injectors enough to blow them off. What needs to happen to get pressure to the regulator as I have not been able to push in the pressure relief valve that you can hook up a pressure guage to and see hear any pressure.
Do the injectors require more pressure to work than they are seeing, the manual call for 43.5 psi with just the key turned on and motor not running?
Can you test the regulator independantly?
Is there a method to see if the injectors are working or recieving a voltage to them IE should there be a measureable voltage at the leads when the key is first turned on to dump fuel into the cylinders?
I measred all of the injector resistances and they where all 12.6 +/- .1 ohm so they check out.
Any help or direction would be great.
Cheers n Beers

 

[99yam40]

Re: 07 F90 low to now fuel pressure question

It would be best to keep it all in one thread instead of starting new ones and not giving the history on the old one,

Maybe they will merge them


A Yamaha service manual and the proper test equipment is a must on these modern motors.
From what I understand you have pressure on the rail but you have no idea what the pressure is.

Pressure regulator regulates rail pressure by opening and dumping excess pressure.

The injectors are pulsed and you need special equipment to see the pulses and measure it from what I have read

 

[rougeaut]

Re: 07 F90 low to now fuel pressure question

Hi ya I was not sure as a first time poster as to starting a new thread or not for a related issue. Either way there seems to be mainly just allot of individuals the just read and not many replies to posts. Even though I thank you very much for the reply the response it is very low level and really not as technical as I had hoped for. I have a manual and know which pressure gauge and the required specifications to use the problem is that there are no measurement points after the Schrader valve to determine the pressure except for as I have done and stated previously.
I would rule out the pressure regulator as it's job is to bleed off over pressure, and I have no measurable pressure although enough to blow off the injectors on the rail by just turning the key on.
Even though this motor only has 215hrs it is a new motor to me so I have ordered from FL a new HP and LP Pump inline filters and damper pump this was only $260.00 the cost here in Vancouver Island Canada for the HP Pump alone is $490.00 just to get a baseline, if at that point here is still no pressure I can move forward knowing that these should not fail me out off shore. Primarily the contamination in the inside of the HP pump filter is what concerns me as it could be corrosion from inside the pump due to salt water ingestion either way for $163.00 I would rather be safe than sorry out on the sea as I have been a Coast Guard Rescue Member in my past.
Just a note if anyone reads this, the best approach to being able to work on any aspect of your boat, motor, trailer etc is to do as the person who replied purchase a manual or on-line manual or study any online documents just to understand and correctly identify the issue.
This could be for safety, to make sure your have the right part, part number for the application etc. once you understand the application and the part and the inputs, outputs of the part then try to validate the part using the right tools even more importantly make sure the that required inputs are being supplied to the suspect parts to rule out a downstream problem. Then make the call to replace the part or fix it, cost is relative to safety and circumstance. But once you correctly know the issue and have tried to test the part or issue then go down to a dealership or such and talk to a mechanic, the guy I spoke to yesterday at the Yamaha dealership offered me a HP pump and VST assemble to try for free to take home but unfortunately he did not have the correct parts but let me know that even though the HP Pump was free flowing that many like this do not provide the right pressure and do not provide the pressure differential across the injectors.
Any who I wish all on this forum the best of luck with their projects.
Tight Lines!

 

[99yam40]

Re: 07 F90 low to now fuel pressure question

You have a PM (private message)