F90 2007 Fuel Pressure Issue and Testing

[rougeaut]

Hi I am a first time poster, I have a new motor to me a 2007 F90TXRF with 215 hrs that had salt water that had been run through the motor. The motor will not start, I did a compression test and it was within spec, there is a healthy fat spark to each plug, the engine turns over and sound like it want to start but no gas to the plugs.
Sorry for the long post but wanted to be complete.
I have flushed the fuel lines with fresh gas, verified the manual pump is working to the Vapor Separator Tank(VST). I removed the VST and it was clean but the High Pressure(HP) electric fuel pump looked corroded, so I cleaned the pump/filter and the rest of the VST tank making sure the float, needed and seat worked well and new inline filter from the manual to the electric pump. I tested the HP electric pump and it flowed at a high level reassembled the VST and primed it by turning the key to the on position 8-9 times to let it run(I could hear it running) still no fuel to the plugs then disconnected the output fuel line to the fuel rail and turned the key on and it flowed fast then reconnected the rail to the injectors and removed the rail and turned the key on, it blew off the injectors so some pressure.
I checked the Schrader valve on the VST before during and after this testing but NO Pressure was released and the manual calls out for 43.5 PSI on the valve with the key on, motor not running. I did this with a cloth and screwdriver to try to check for any pressure.
Q) As this test point is not on the output of the high pressure electric pump and opens up to the inside of the VST does it really see 43.5 psi and if I turn the key off how much pressure does it hold or does the pressure reduce right away as I did not had a gauge on it. I will buy a gauge soon if needed.
When I pulled the injectors out they had a bit of gas on the back side so I assume that there is not enough pressure differential across the injectors for them to work. I also noticed that the fuel pressure regulator does not seem to block the flow from the output of the HP pump but it does appear to control the gas from the bottom of the VST through the gas cooler mounted on the back of the VST the manual stats the regulator's job is to vary the opening on the return line to restrict flow so if this is not working then I would have no pressure is that correct?
How do I test the fuel regulator or should I buy a new one as I am sure it must have had some salt water in it a some point.
I believe that if I can get the pressure to the injectors the motor will run it may need to have the injectors cleaned but at least it will run.
PS is it possible to remove the fuel filter from the back of the injectors without wrecking them?
ANY HELP or guidance on how to test the setup would be great, I don’t mind buying news fuel pumps and such but would like to get the motor running to start with.
THANK YOU and Tight Lines!

[rodbolt17]

if you dont mind buying things why not buy a fuel pressure tester and test rail pressure?
doesnt matter about any pressure differential, the injectors dont rely on pressure to trigger them.
much below about 30 psi on the rail and it quits running.

[99yam40]

[QUOTE=rougeaut;70893
I checked the Schrader valve on the VST before during and after this testing but NO Pressure was released and the manual calls out for 43.5 PSI on the valve with the key on, motor not running. I did this with a cloth and screwdriver to try to check for any pressure.
[/QUOTE]

Maybe the Shrader valve is plugged, If the rail has enough pressure to pop the injectors off of the rail there has to be some pressure that could be measured with the proper equipment

[rougeaut]

Hi Thanks Yes I am off to buy a fuel pressure tester today, and as to 99Yam40 about the Schrader valve I pulled it out yesterday and checked it so it does not seem pluged or stuck.
I would like to test the pressure regulator itself, when you look at the output of the hp electric pump it goes directly out to the fuel rail so I guess the regulator restrictes the output of the pump to increase the pressure.
I understand the ECM controls the voltage to fire or pulse the injectors and need to get as you mentioned the required pressure for them to work so I will try to measure the pressure and go from there.
Anyhow thanks again for the feedback

[rougeaut]

Hi as an update to this issue I learned a couple things today. Firstly the schrader valve I reffered to as i mentioned is only opened to the VST tank, for the purpose draining the tank and not in the high pressure output line. My motor does not have a test point from the output of the VST to the Fuel rail or even on the plastic fuel rail so I spliced in a fuel gauge I bought and with the key turned to the on position and motor off the pressure is right at 43-44 PSI or to spec as long as the pump runs for about 4-6 seconds then drops off to about 10 psi is that ok or should it hold the 43psi maybe my connections were not tight enough but there was no fuel leaks. Also when the motor is truned over the fuel gauge reads between 42-44psi or there abouts so the pressure is there and I am happy.
I had the motor turned over and I felt the injectors and listened but it was really hard to heard or feel the injectors clicking I think they were a bit but not sure?
I measured the injectors and they were all at 12.6 ohm +/- .2 ohms and I put a volt meter accorss the injector connector and saw a voltage as the motor turned over but it was to fast for my meter and I do not have an oscillosscope.
Q) Can I pull the filters out of the back of the injectors to see if that is clogged as the motor had salt water run through it? Or how do independantly test the injector? apply 12V accross them and wee if they open?
Anyhow I am glad that the pressure is to the injectors!
Cheers and thanks for any info!

[Pbailey15]

From what ive read, you should send your injectors off to be cleaned and tested. Requires special equipment to pressurize and run solve tw through them. Cost appears to be around 25 per.

I need to check pressure as well. Can you describe where you spliced your gauge in?

Thanks

[rougeaut]

Hi ya I would have to mail my injectors out to be cleaned that is why I would like to see if I can remove the injectors i saw it done on youtube but it looks rather destructive?
As for the fuel pressure measurement I was able to leave the intake and VST inplace and just remove the regultor to get enough room to unclamp the fuel high pressure rail line and slide it off with a large screwdriver, Then in my fuel pressure gauge kit it had a plastic tee with a threaded end on it that the gauge screws onto and it came with extra fuel lines and hose clamps. So just attach one fuel line back onto the high pressure output to the tee and the other end of the tee inot the exisiting fuel line hose then reattach the quick connect and regulator and yer done. Just turn the key on but do not start the motor and as the electric pump runs inside the VST you should see the pressure reading.
Cheers and good luck

[rodbolt17]

some folks simply over complicate a simple speed density EFI setup.
again, pressure does not pop off the injectors, thats a diesel mentality thingy.
what you do is purchase the correct fuel gauge adapter for that engines quick connect and go from there.
the regulator is on the VST return path.

[99yam40]

Rodbolt,
I took it that the statement "then reconnected the rail to the injectors and removed the rail and turned the key on, it blew off the injectors so some pressure." meant that they truly (physically)popped off the rail.

[rougeaut]

Hi Thanks for the reply guys, the yamaha service guy said to do a quick try for pressure and It DID blow the injector off of the rail(rail removed) but the electric harness saved it from going to far :-)
I bought a Fuel gauge and found the required 43 PSI on the rail with the key on and around 42-44 PSI turning the engine over so we should be good there.
I just got back from a 5 hr return drive to an injector specalist that cleaned the injectors and did the flow and spray pattern test but found that one of my injectors is siezed, he did the cleaning 3 times on it but he said the needle was frozen. The other 3 injectors were within 15-20% of each other so they were working but now these 3 are all good for flow and spray pattern so $100.00 and need 1 injector. Having said that the motor should have fired with 3 of 4 injectors working so it seems that the signals or pulses to the injectors are not correct as I have a fat spark on all plugs and even pressure from the compression test. The guy showed that even with a multi meter we saw around 7 Vdc pulsing the injector on his system.
S I guess I have to buy an new injector and try to find the issue for the firing I will measure the votage to the connectors with a digital multi meter to the injectors? this should be the last problem to resolve this as the plugs are very dry with compresion and spark?
Please Let me know if you have any insightfull comments as I could be making some rookie mistake here?
Thanks!

[rougeaut]

Injector firing testing question with info

Hi well I put the injectors back in and without the electrical connectors on, with the key turned on the voltage accross the two pins read 11.2 Vdc for each.
When the motor was turned over for 4-5 secs the voltage accross the connectors was 8.43 Vdc on each. I know from yesterday these injectors fire when tested at 7 Vdc and the motor turned over very fast.
So with the right 43.5 psi on the fuel rail to the injectors and this voltage present there is still no gas at the plugs? they were moist but not wet and NO gas smell on them???
I tried again to listen and feel the injectors clicking but as they are into the rail and the intake only a very small area is present so I put a steel rod onto them and listened but still could not feel or really hear them.
As I just had the injectors serviced yesterday I know that 3 of them work great and to spec.
Any thoughts as to the next step? Like put a DC light bulb accross the connectors to see if there is enough curent to drive the soleniods in the injectors
Any helpfull feedback would be great if not them it may have to go to the mechanic to get the codes read or whatever they recommend?
Cheers and Thanks!

[rougeaut]

Got Fuel trough the injectors YE HA

Hi well another step forward as I took off the fuel rail and secured the injectors into a plastic container and turned the motor over and yup the 3 working injectors fired(one is sized as I had them serviced the other day and no one on Vancouver Island has any in stock, they have many for the larger motors 115+ but say these never die) and had a good spray out of them so I know that the electrical is OK I have the 43 psi and all I have to do is pay 237 + tax @ 13% for 1 injector. The cheap ones at injector wharehouse are out of stock.

Q) The compession was to spec, and the spark was healthy for each cylinder and now I Know the fuel is shooting out so where is the problem?

Could the throttle body be staing shut on start up for reduced intake? reducing the air flow into the cylinder? As every time I turn it over for a while the motor sounds like it wants to start like very close and even will backfire a tiny bit with almost a white smoke out of the air silencer that seems to indicate a lean condition. All the while the plugs appaer almost moist but not wet or smelling of gas.
I really don't know which step apart from getting the other injector ASAP is any hints?
Cheers n Beers

[rodbolt17]

air valve is fixed, DO NOT play with it.
idle air and startup air is via the ISC valve.
wait for the new injector and try again.
a standard multi meter wont display injector firing voltage correctly as its only on for several milliseconds.
a peak reading meter will catch it but a standard digital is to slow and will give an average voltage.
the red/yellow wire have 12V anytime the key is on.
the ECU controls the ground path to operate the injectors.

[rougeaut]

Hi rodbolt17, I have ordered a new injector, I tried to spray some carb cleaner into the intake but still didn't start when turning over. I removed the intake manifold and plugs and turned over the engin by hand and saw all of the intake valves open into the cylinders so no blockage.
I brought the #1 piston to TDC on the commpression stroke and check the timing marks but they don't look right so I will read up on this today here is a pic what do you think could this be the problem?
Thanks for your insight!

[rougeaut]

Could the belt be loosened and the cam sprockets be aligned with the #1 at TDC on the comp stroke and the flywheel mak aligned and then rotate the engine twice to see if they realign, I don't think the flywheel key is sheared.
HUMMMM