200hp VMAX EFI-- no start

[craigmanns]

Took the boat out last week. It ran terrible at idle speed but on plane seemed to run fine.
Now the boat won't even start.
When the boat was running bad- Neither Tach registered RPM. Digital read Zero analog is stationary
Yesterday checked fuel pressure- zero. Only got 11 volts going into the high pressure fuel pump. Long story short, If I hook up a good ground to the Fuel pump The pump spins up to about 40psi.Traced the blue (ground) wire back to the CDI unit. But even with the fuel rail pressurized the boat still won't start. Maybe not enough voltage to fire the Injectors?
I am getting spark at the plugs.

Did a fairly thourough visual check, replaced some connections, but still no start.
At this point I need some suggestions.

 

[craigmanns]

Re: 200hp VMAX EFI-- no start

Pulled the fuel rail after manually pressurizing high pressure pump and while cranking engine getting no gas whatsoever out of any of the Fuel injectors.

 

[rodbolt]

Re: 200hp VMAX EFI-- no start

stop
wiat for jefferson to post.
then wait again.
be back with ya in the AM.
but here is a good one for a recent MMI grad to post on.
simple and straight fwd.

 

[craigmanns]

Re: 200hp VMAX EFI-- no start

I'll be waiting. I was to the point where I was about to take it to mechanic, cause I am pretty darn clueless. But if it's what I'm thinking--- I am gonna be crying.

 

[craigmanns]

Re: 200hp VMAX EFI-- no start

Thanks Rodbolt,
This is my first experience working on my yamaha. But I'm trying to muddle through this thing.
I'll be waiting. I was to the point where I was about to take it to mechanic, cause I am pretty darn clueless. But if it's what I'm thinking--- I am gonna be crying.

 

[rodbolt]

Re: 200hp VMAX EFI-- no start

ok
some quick tests, does the engine crank over normally?
when you turn the key to on does the fuel pump power up for about 3 seconds?
the blue wire is the pump ground path, the ECU controls it.
at key on the ECU completes the ground path for about 3 seconds.
then if the engine isnt running it opens the circuit.
the pump red wire should show 12V to engine ground anytime the key is on.

 

[craigmanns]

Re: 200hp VMAX EFI-- no start

Engine turns over normally and strong.
Fuel pump does not turn on at all.
When referenced to engine ground I have 12v plus at the red wire.
When I used the Blue wire I only get 11 volts.
If I connect the blue wire straight to ground the pump spins. Looks like I am not getting a good enough ground from the ECU unit.

 

[craigmanns]

Re: 200hp VMAX EFI-- no start

Rodbolt, Thanks for your help so far.

I could add that the boat wasn't ran for a month before I took it out and it started running bad.

Could this be a bad ground to the ECU?

 

[rodbolt]

Re: 200hp VMAX EFI-- no start

could be a bad ECU ground, could be a failing pump.
check the pump resistor and test the pump current draw at key on power.
with the key on engine OFF rapidly open the throttle, listen at the fuel rail for a buzzing sound when the throttles are rapidly moved to wot.

 

[jeffersondodson561]

Re: 200hp VMAX EFI-- no start

I am assume that this is the OX66 VMAX series. If you can connect a ground and the fuel pump and it turns on then their is a path that is restricted. Being it happens at idle and WOT is ok I would first check the main power relay probably not but second I would check the Fuel Pump resistor. The resistor is their to allow more charging output at lower rpms. Obviously I would all connections too.

 

[craigmanns]

Re: 200hp VMAX EFI-- no start

Thank you both for your reply's,
It is an OX66.

Im Not sure about the main power relay. Is it on the starboard side of the engine under a plastic cover with two heavy duty looking fuses in it? And if it were the main power relay wouldn't it just take out the voltage? I do have 12V+ with reference to a good ground at the pump. Only time I don't have the solid 12 is if I use the blue wire coming from the CDI for ground. If I completely isolate the pump and measure the voltage that would be going to the pump I only get 11 volts.

Where does the ground for the Injectors come from?

Could one of you tell me where I can find the fuel pump resistor? And How many ohms I should read? Would a fuel pump resistor also take out the tach?

Sorry for asking so many questions, Don't have very much experience.
Again, Thanks for any and all help.
CM

 

[craigmanns]

Re: 200hp VMAX EFI-- no start

Thanks again guys.

I should be finding out shortly where the resistor is located......And I will check for the buzzing sound on the fuel rail when I get home. Is this the pump running at WOT? And should I then see fuel pressure at the rail with a pressure gauge?

Not sure if I can accurately check current with my DVM/ cause I think the max it reads is milliamps. But I'll let ya know.

 

[rodbolt]

Re: 200hp VMAX EFI-- no start

always remember, the ECU completes OR removes the ground path for pump run functions AND injector on time functions.
no path no working circuit.
so at key on the ECU completes the ground path for the pump for about 3-5 seconds, if no run signal from the pulsers it will then remove the ground and the pump quits.
the injectors are supplied 12V anytime the key is on, the ecu toggles the ground path as nessasary to fire the injectors.
the buzzing with key on engine off at rapid throttle opening is the injectors fireing.

 

[craigmanns]

Re: 200hp VMAX EFI-- no start

Thanks again Rodbolt,
I checked the ground connections to the CDI box. Looked good pulled one off and cleaned and put it back. Checked the others using ohmeter. No difference.
Checked the pump resistor it is .8 ohms. From what i read it should be .53-.57ohms. Is this out of tolerance enough to cause my issue? And is it even in use with key on position?
Also checked resistance across the motor and it was only .6 ohms. Not sure but that seems to me like it should be alot higher than that. Might not even mean anything cause the pump works when I provide a ground.
Almost forgot. there was no buzzing when going WOT in on position.
And I am pretty sure the pump wasn't pulling any current with key on position.
I sure hope we can come up with something besides a CDI.
Thanks,
CM

 

[rodbolt]

Re: 200hp VMAX EFI-- no start

jeffersondodson, you wouldnt happen to have a VX200 wiring diagram you can post?
craigmans, we gotta work on your understanding of voltage VS current and why.

 

[craigmanns]

Re: 200hp VMAX EFI-- no start

Are you telling me it's not the CDI? With the .6 ohms at the pump input I was thinking it was just shorting out due to bad pump, but it doesn't make any since that the pump runs with an external ground.

 

[rodbolt]

Re: 200hp VMAX EFI-- no start

wait a bit, BRB I hope.

 

[rodbolt]

Re: 200hp VMAX EFI-- no start

.6 ohms across the pump is ok.
google ohms law, do the math, tell me why you have 11v with key on engine off between the blue pump wire and ground.



thats why I hope jefferson has a diagram in his laptop to post.
I dont, dont need it.
do you realize what your checking when doing a resistance check from pump red to pump blue? and do you realize that check must be done with both wires disconected?

 

[craigmanns]

Re: 200hp VMAX EFI-- no start

I am totally grasping for straws here. I know you know what you are doing. I was just hoping if I provided enough information on here you would be able to tell me what is wrong with this thing before I drop it off at a mech who may or may not know what they are doing.

Is there anything else I need to check? Or do you already know what is wrong with it?

 

[rodbolt]

Re: 200hp VMAX EFI-- no start

NO I dont know whats wrong with it.
I am behind a monitor trying to gather enough information to shoot you on the way.
however in my shop, with my test egipment and my knowledge this issue would have been resolved.
trust me, its most likly not ECU involved.
its gonna be something stupid.
possibly a repeat fuel system issue. it happens.

remember what I keep whacking on the ECU supplys the ground path fo ALL engine functions except SWb.
ok, key on engine off.
red meter lead on the pump red lead, black meter lead to engine block.
12V would be ok.
move red meter lead to the blue wire and 11V would be about right cause the ECU has opened the ground path.
normal current draw on the HP pump is 3.5 to about 5 amps, more and something is bad wrong.
its not something any yamaha RTA nor any MMI instructor knows.
it simply comes from dealing with out of warrenty motors for 15 years.