2008 yamaha nytro lean afr

[Nytroed]

The lights change with RPM? Or they just cycle back and forth initially when you first start the machine? The Boost Fuel mode colored light lights up when you rev it up and make boost and not on all the time it's running?
If this is true, go after a fuel supply issue.

The lights change when reving I'm starting to think I'm dumb for not chasing fuel when I learned of this lol I figured it was a fault in the injectors and stuff or a melted piston or something of the sort. Will older fuel cause Afr to be lean as well? Just so when I pull the tank I will drain it or leave it?

 

[Nytroed]

Well that isn't quite right either... Normally a fuel pressure regulator's vacuum/boost reference line shouldn't be plumbed to the air box. That is just going to cause more driveability issues like backfires or stalling because when you chop the throttle closed after being under load / boost and the intake port side of the throttle bodies immediately go to vacuum while the air box is still under boost pressure the FPR will still maintain a raised fuel pressure at the injector tips while the engine doesn't demand it (injector tips are exposed to vacuum) which flogs the engine super rich like it's been choked until the boost pressure in the air box drops off... The FPR should sense vacuum so it pulls fuel pressure away when increased fuel isn't required like at idle or when you let off the throttle...

I am going to check where exactly the regulator ties into I may have typed that wrong it may be tied into a vacuum line. I looked around at it the other night but it was getting pretty dark. I will update what I find on the lines and pressure. The fuel pump it has has the better crimp hose clamps and I will have to cut them and put twist style on. What's the easiest way to find out if I have in in tank pump? Guessing remove the tank and look? Lol

 

[mbarryracing]

Fuel pressure gauge will tell the tale now.
No, old fuel will not create that lean of an AFR. It will cause misfires but you'd hear that.
I'd dump it though unless it's less that 30 days old.

Take the fuel cap off, look down inside the tank for a plastic sending unit that will have a pump inside. Search this forum, there are threads with pic's of in-tank sending units.

 

[thor452]

I think it is a blue light that comes on when the gems sees boost. a super charger will not build boost on a stand either not much if any you have to give it load you can hold the brake and give it some throttle this will smoke your belt but will allow you to build boost. I had the same issue with my apex right out of the box the gems was not reading boost. had to have them send me a new unit and then it worked fine. was exact same issues as you would go good and as soon as it would build a little boost it would go crazy high. sounds to me like your fuel pump is junk by what you are describing with the noise. I would make sure the boost light is lighting up on the gems and then investigate that pump.

 

[mbarryracing]

thor452,
Here is another way to look at it then too. If it's not building much boost on the stand then there also isn't a demand for much added fuel either so even if the GEMS boost mode wasn't working I'd think it shouldn't lean out the AFR that much to wheeze out & not even rev up.
Heck, the stock FPR on the Apex alone by itself will compensate for enough fuel for up to 2 psi boost without an extra controller... look at the G force Yamcharger that doesn't use any controller, relies on the stock FPR.
If truly his sled goes that lean at higher RPM and wont rev up on just a jack stand, I'm "leaning" more and more towards that his fuel pump can't supply enough fuel to support higher RPM's demand alone, even without boost.

 

[Nytroed]

I think it is a blue light that comes on when the gems sees boost. a super charger will not build boost on a stand either not much if any you have to give it load you can hold the brake and give it some throttle this will smoke your belt but will allow you to build boost. I had the same issue with my apex right out of the box the gems was not reading boost. had to have them send me a new unit and then it worked fine. was exact same issues as you would go good and as soon as it would build a little boost it would go crazy high. sounds to me like your fuel pump is junk by what you are describing with the noise. I would make sure the boost light is lighting up on the gems and then investigate that pump.

The boost light comes on when I give her fuel

 

[Nytroed]

Fuel pressure gauge will tell the tale now.
No, old fuel will not create that lean of an AFR. It will cause misfires but you'd hear that.
I'd dump it though unless it's less that 30 days old.

Take the fuel cap off, look down inside the tank for a plastic sending unit that will have a pump inside. Search this forum, there are threads with pic's of in-tank sending units.

OK sounds good I will look. If it is bad pressure or not enough should I put a new in line and in tank or just one in the tank?

 

[Nytroed]

thor452,
Here is another way to look at it then too. If it's not building much boost on the stand then there also isn't a demand for much added fuel either so even if the GEMS boost mode wasn't working I'd think it shouldn't lean out the AFR that much to wheeze out & not even rev up.
Heck, the stock FPR on the Apex alone by itself will compensate for enough fuel for up to 2 psi boost without an extra controller... look at the G force Yamcharger that doesn't use any controller, relies on the stock FPR.
If truly his sled goes that lean at higher RPM and wont rev up on just a jack stand, I'm "leaning" more and more towards that his fuel pump can't supply enough fuel to support higher RPM's demand alone, even without boost.

I agree on this. I would about bet if I were to remove the supercharger belt that it would still be lean. I am leaning towards the pump after talking to mbarry

 

[thor452]

I think you are correct there. Squeaky wheel if you will. Pun Intended. I wonder if you can get an in the tank fuel pump that will replace both?

 

[mbarryracing]

... should I put a new in line and in tank or just one in the tank?

The stock in-tank pump on the Nytro's (if they were still strong and not weakened from being run out of gas once or twice) petered out around 6 psi boost with the stock FPR-less return-less fuel rail.
I'm sure a stock in-tank pump is sufficient for your 180 kit, and even a little more when used in conjunction with that external FPR.
The in-line external pump & FPR was an upgrade required to support fuel flow demands of higher boost / HP levels.

Again, search this forum, there are threads where guys upgraded their in-tank pumps if that's the route you want to take.

 

[Nytroed]

The stock in-tank pump on the Nytro's (if they were still strong and not weakened from being run out of gas once or twice) petered out around 6 psi boost with the stock FPR-less return-less fuel rail.
I'm sure a stock in-tank pump is sufficient for your 180 kit, and even a little more when used in conjunction with that external FPR.
The in-line external pump & FPR was an upgrade required to support fuel flow demands of higher boost / HP levels.

Again, search this forum, there are threads where guys upgraded their in-tank pumps if that's the route you want to take.

So fuel pressure on first key turn runs to about 43 psi. Then if you do a very fast throttle slam it drops to 30. Pump doesn't seem to be pumping volume very well when it's put into a jug it pumps good for a second then kinda sputters out on volume then shuts off.

 

[mbarryracing]

It shouldn't drop with a fast throttle slam.
When key-on the fuel pump relay only cycles for a few seconds to prime the system then shuts off if the ECU doesn't see the engine running.
When you say it's put in a jug, you mean it's still sucking from the sleds tank and pumping into a jug? Did you determine if there is an in-tank pump still in the tank?

 

[Nytroed]

It shouldn't drop with a fast throttle slam.
When key-on the fuel pump relay only cycles for a few seconds to prime the system then shuts off if the ECU doesn't see the engine running.
When you say it's put in a jug, you mean it's still sucking from the sleds tank and pumping into a jug? Did you determine if there is an in-tank pump still in the tank?

Spoke with mpi on replacement pump he heard the sound and sounds bad. It is pulling from the tank dumping into a jug. The in tank pump may be in place but there are no wires to it. I pulled the seat and saw that much lol

 

[Nytroed]

Currently has a walbro pump

 

[mbarryracing]

You have to determine how that external screeching in-line pump is getting fed. Gotta find out if there is a restriction on the supply side, like it's trying to draw fuel thru the old remnant in-tank pump & sending unit which would be very very bad. Hopefully someone deleted the in-tank sending unit and replaced it with some sort of rigged-up low restriction fuel pickup, doubtful though if the last owner was dumb enough to beat on the clutch with a hammer...