2008 yamaha nytro lean afr

[Nytroed]

I have a 2008 Yamaha nytro I have had for 3 years and haven't gotten it to run correct yet. SO here's my problem the sled had a 240 kit and was dead so installed a 180 kit had the clutch sent to Schmidt bros and awaiting to tune it until I can get the motor running right. It cuts out when pulling and the Afr runs lean when it cuts out. Would this be fuel pump failing? I'm stumped where to even start. I can turn the fuel controller all up and still lean. Mpi has been 0 help when I have contacted them.

 

[kingtut]

It cuts out when pulling and the Afr runs lean when it cuts out. .

This is WOT right? I'm presuming the injectors can handle it and i would guess if it was the fuel pump it wouldn't right right ever right?

 

[Nytroed]

This is WOT right? I'm presuming the injectors can handle it and i would guess if it was the fuel pump it wouldn't right right ever right?

Yessir it seems to be at wot. It is embarrassing that my brothers phazer being stock will stomp a 180 nytro with mountain tamer skid different track and all the fancy stuff. Just doesn't make sense for the controller to be maxed out and be lean. I think I'm running 7-8# boost and I'm at 7-10 in elevation. It has an aftermarket mpi fuel pump with the regulator. I ordered a fuel pressure gauge to see if that's the problem. The fuel pump almost seems to be slow at starting then goes to a fast screech then shuts off when pressured or is on a timed relay.

 

[kingtut]

Let us know how the fuel pressure looks. Got a video of what it is doing by chance?

 

[Nytroed]

Let us know how the fuel pressure looks. Got a video of what it is doing by chance?

I have no video I should have over the winter. I will let you know on the fuel pressure. I read somewhere that they are supposed to run 39 psi?

 

[Nytroed]

So I lifted the track and 13.9-14 at idle 11.2 at 2500rpm 13 at 3000 Afr then a fast roll into full it jumps to 20s-30. 1.5 # at idle. Pressure Gauge hasn't showed up yet any thoughts with new info?

 

[kingtut]

So I lifted the track and 13.9-14 at idle 11.2 at 2500rpm 13 at 3000 Afr then a fast roll into full it jumps to 20s-30. 1.5 # at idle. Pressure Gauge hasn't showed up yet any thoughts with new info?

Can't recall what is normal for boosted sleds again.

 

[mbarryracing]

Yessir it seems to be at wot. It is embarrassing that my brothers phazer being stock will stomp a 180 nytro with mountain tamer skid different track and all the fancy stuff. Just doesn't make sense for the controller to be maxed out and be lean. I think I'm running 7-8# boost and I'm at 7-10 in elevation. It has an aftermarket mpi fuel pump with the regulator. I ordered a fuel pressure gauge to see if that's the problem. The fuel pump almost seems to be slow at starting then goes to a fast screech then shuts off when pressured or is on a timed relay.

YOU THINK YOU ARE RUNNING 7-8# BOOST ???!!! To start with, you NEED TO KNOW... It's the first of the golden rules of Boosting! The second rule is follow the first rule!
What was wrong with the original 240 kit that makes you say it was dead? You might have a common gremlin.
The controller maxed out should flood the engine rich, seeing it shows way lean at WOT could indicate an insufficient fuel supply issue. If you have a misfire, the AFR will also show lean because the O2 sensor will sense unburned air that gets passed right thru the combustion chamber into the exhaust... that can be very misleading also so be conscious of that too.

Third golden rule is MUST have an AFR gauge, which you have...

Fourth is, if you have an aftermarket fuel pump and pressure regulator, in order to get the base set right you need to know what your fuel pressure is. There is no "ball park" wing it and see how it runs...
Is the aftermarket MPI fuel pump you speak of, that is "screeching", an external in-line supplemental pump (feed by stock in-tank pump) or a replacement in-tank pump? Fuel pumps screech due to cavitation from fuel starvation or supply side restriction. In any case, that is a bad sign and that pump is most likely wounded now. A symptom of a failing fuel pump can be a drop in fuel pressure as volume demand goes up (linear to a rise in boost pressure). If it's an external in-line type, the stock in tank pump might not be feeding it correctly. They need to run together at all times so the in-line is NEVER starved.

Is the aftermarket fuel pressure regulator a boost referenced style? If so, make sure the boost line is hooked up to it or it wont raise fuel pressure to match an increase in manifold pressure (boost).

So know what your boost pressure is. If you don't know because you don't have a boost gauge, get one.
Wait for your fuel pressure gauge to come in then install it. Know what your base fuel pressure is at, set it if it's not at stock spec.

Most turbo sleds wont build max setting boost on a jack stand because there isn't enough load on the engine, but it should rev up cleanly at WOT regardless. It will allow you to at least see what your fuel pressure is doing. As RPM's go up under load, the pressure at a minimum should never droop below the base pressure. It should rise 1:1 with boost pressure. If the pump is bad, you will see it tail off and drop under load.

 

[Nytroed]

YOU THINK YOU ARE RUNNING 7-8# BOOST ???!!! To start with, you NEED TO KNOW... It's the first of the golden rules of Boosting! The second rule is follow the first rule!
What was wrong with the original 240 kit that makes you say it was dead? You might have a common gremlin.
The controller maxed out should flood the engine rich, seeing it shows way lean at WOT could indicate an insufficient fuel supply issue. If you have a misfire, the AFR will also show lean because the O2 sensor will sense unburned air that gets passed right thru the combustion chamber into the exhaust... that can be very misleading also so be conscious of that too.

Third golden rule is MUST have an AFR gauge, which you have...

Fourth is, if you have an aftermarket fuel pump and pressure regulator, in order to get the base set right you need to know what your fuel pressure is. There is no "ball park" wing it and see how it runs...
Is the aftermarket MPI fuel pump you speak of, that is "screeching", an external in-line supplemental pump (feed by stock in-tank pump) or a replacement in-tank pump? Fuel pumps screech due to cavitation from fuel starvation or supply side restriction. In any case, that is a bad sign and that pump is most likely wounded now. A symptom of a failing fuel pump can be a drop in fuel pressure as volume demand goes up (linear to a rise in boost pressure). If it's an external in-line type, the stock in tank pump might not be feeding it correctly. They need to run together at all times so the in-line is NEVER starved.

Is the aftermarket fuel pressure regulator a boost referenced style? If so, make sure the boost line is hooked up to it or it wont raise fuel pressure to match an increase in manifold pressure (boost).

So know what your boost pressure is. If you don't know because you don't have a boost gauge, get one.
Wait for your fuel pressure gauge to come in then install it. Know what your base fuel pressure is at, set it if it's not at stock spec.

Most turbo sleds wont build max setting boost on a jack stand because there isn't enough load on the engine, but it should rev up cleanly at WOT regardless. It will allow you to at least see what your fuel pressure is doing. As RPM's go up under load, the pressure at a minimum should never droop below the base pressure. It should rise 1:1 with boost pressure. If the pump is bad, you will see it tail off and drop under load.

Hey want to call me and talk that over? Lol well it's hard to know my boost levels when the clutch isn't adjusted. To make a long story short the sled ran weird when I got it and the in line fuel pump has screeched since I have gotten the sled. The 240 super key hole was wobbled out due to neglect from previous owner with I found out when I pulled it into my shop and inspected it. So I sent it to mpi to see if they could rebuild it and they said the shafts were spinning on each other. So I replaced it then I sent my clutch to Schmidt bros because it seemed galled up and not right to me. And that clutch was trash the previous owner took a hammer to it or something ignorant like that. So now I have to set the clutch to the sled by taking some off the fly weights. It only wraps to (7400) I think sorry I'm not 100% it's been a while since I have ran it and I lost my notes I had on it. But it was 800 rpms of full throttle. And the boost factor I can't recall if it was 7 or 8 pounds. The fuel regulator was the one it came with that mounts on the fuel rail that then has a line that runs to the intake side that connects a t to the gems and intake side. But serious on the call me if you need more info on anything. The fuel gauge is one you tie into on a line read it then remove. Should I install a huge for constant measurement?

 

[Nytroed]

So the sled also has an aftermarket tank. I am not sure if it still has the in tank pump or if it was removed. It will not start with the in line pump wires disconnected. Do they need the in line and the in tank?

 

[mbarryracing]

The fuel regulator was the one it came with that mounts on the fuel rail that then has a line that runs to the intake side that connects a t to the gems and intake side. But serious on the call me if you need more info on anything. The fuel gauge is one you tie into on a line read it then remove. Should I install a huge for constant measurement?

Nytroed,
Now we have a few more details (clear now you have a SC and not a turbo) and you might have also provided a few more clues...

When you say the line runs to the intake side and a Tee to the GEMS, do you mean the vacuum port on the throttle bodies or the Air Box side port? The reason I ask is that if the boost reference line for the GEMS fuel controller is connected to a vacuum signal, that might have ruined the little internal pressure sensor. I recall that I've had similar Dobek controllers that no longer added fuel / ran lean (boost fuel mode light lit up all the time) after being hooked to vacuum because that they were meant for positive pressure only, supposed to be plumbed into the airbox side. I'm not positive if it's the same with the GEMS version but in any case, it likely isn't working anymore (not seeing boost) and therefore likely not adding fuel regardless of settings. That would DEFINITELY cause your lean issue... I'd start troubleshooting there.

One way to tell is when running the engine up in RPM and boost on a jack stand (since a SC it will build boost based on RPM and not load like a turbo), the controller boost mode lights should change as the pressure increases, as it sequences from one mode to the next... If it is no longer sensing boost pressure, there will be no change...

As far as the fuel pump goes, it shouldn't screech, period. It should whine and buzz, but screeching indicates it has a big restriction on the intake / suction side. Like it's trying to draw thru a non-functioning in-tank pump, or if your aftermarket tank doesn't have an in-tank pump then the pickup is too restrictive for the capacity for that in-line. You can learn from my mistakes...
In any case, that pump is junk now too. If the GEMS controller is functioning correctly, and your fuel pump has a restriction like that it will also restrict that pumps volume & pressure capability and could cause a fuel starvation symptom under boost. Or heck, it could be a combination of BOTH!
The regulator is likely set OK since it's a MPI standard issue, but it can't compensate for a bad controller or pump.

 

[Nytroed]

Nytroed,
Now we have a few more details (clear now you have a SC and not a turbo) and you might have also provided a few more clues...

When you say the line runs to the intake side and a Tee to the GEMS, do you mean the vacuum port on the throttle bodies or the Air Box side port? The reason I ask is that if the boost reference line for the GEMS fuel controller is connected to a vacuum signal, that might have ruined the little internal pressure sensor. I recall that I've had similar Dobek controllers that no longer added fuel / ran lean after being hooked to vacuum because that they were meant for positive pressure only, supposed to be plumbed into the airbox side. I'm not positive if it's the same with the GEMS version but in any case, it likely isn't working anymore (not seeing boost) and therefore likely not adding fuel regardless of settings. That would DEFINITELY cause your lean issue... I'd start troubleshooting there.

One way to tell is when running the engine up in RPM and boost on a jack stand (since a SC it will build boost based on RPM and not load like a turbo), the controller boost mode lights should change as the pressure increases, as it sequences from one mode to the next... If it is no longer sensing boost pressure, there will be no change...

As far as the fuel pump goes, it shouldn't screech, period. It should whine and buzz, but screeching indicates it has a big restriction on the intake / suction side. Like it's trying to draw thru a non-functioning in-tank pump, or if your aftermarket tank doesn't have an in-tank pump then the pickup is too restrictive for the capacity for that in-line. You can learn from my mistakes...
In any case, that pump is junk now too. If the GEMS controller is functioning correctly, and your fuel pump has a restriction like that it will also restrict that pumps volume & pressure capability and could cause a fuel starvation symptom under boost. Or heck, it could be a combination of BOTH!
The regulator is likely set OK since it's a MPI standard issue, but it can't compensate for a bad controller or pump.

The gems and fuel fuel reg are on the air box lol and I will hook up that fuel gauge today and see what my pressure is. How big of a pain are those fuel tanks and stuff to work on like pulling it to where you can get to the in tank pump?

 

[Nytroed]

The lights change on the gems

 

[mbarryracing]

The gems and fuel fuel reg are on the air box lol

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...

 

[mbarryracing]

The lights change on the gems

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.