Non-Adjustable Fuel Pressure Regulator

[jonlafon1]

Clutching is a huge factor in gas mileage.. Its just something I don't get to crazy about(gas mileage lol). Pretty sure I beat the wifes old 8000 cat at the pumps also.. Only thing we do is fill them the same when we gas and see who uses what.. I bet if I tone it down and really tried to get mileage I could beat the stocker GT i run with even more.. MS 17 is a good tune for trails, but make sure you got good fuel especially if its COLD.. Powertrail is what I use alot just because its not as picky about fuel and its still a good rip.

 

[Doc Harley]

Clutching is a huge factor in gas mileage.. Its just something I don't get to crazy about(gas mileage lol). Pretty sure I beat the wifes old 8000 cat at the pumps also.. Only thing we do is fill them the same when we gas and see who uses what.. I bet if I tone it down and really tried to get mileage I could beat the stocker GT i run with even more.. MS 17 is a good tune for trails, but make sure you got good fuel especially if its COLD.. Powertrail is what I use alot just because its not as picky about fuel and its still a good rip.

X2 on the Powertrail very strong and most likely the highest tune you can run on pump 91, without issues. (still compiling data) lol.
Clutching..... Understand.
Going to set up clutching for Powertrail (max rpm) and work around those Perimeters. Nope...ill never be the fastest. But ill do the best I can.

 

[jonlafon1]

X2 on the Powertrail very strong and most likely the highest tune you can run on pump 91, without issues. (still compiling data) lol.
Clutching..... Understand.
Going to set up clutching for Powertrail (max rpm) and work around those Perimeters. Nope...ill never be the fastest. But ill do the best I can.

Fore sure.. Don't overthink this! I think you should at the very least have AFR guage on your sled.. Still nothing like data logging but still gives a you a idea when you get shitty fuel and running lean when its -5 the morning you hit the trail.

 

[Turboflash]

He who burns the most gas is having the most fun?!

 

[Doc Harley]

Fore sure.. Don't overthink this! I think you should at the very least have AFR guage on your sled.. Still nothing like data logging but still gives a you a idea when you get shitty fuel and running lean when its -5 the morning you hit the trail.

With this f'd up weather I don't think I'll ever see -5°. Lol. Every time I go out it's been 30°. I'm ready to lose my mind haha.
BTW, you guys talked me into O2 sensor. I paid attention to it while cruising, 11.9 - 12.5. I was riding with a serious thug on a '24 900r with 3 miles on it. I couldn't get him to slow down...
Me: say bud, this isn't a race. Hahaha bastard!!!

 

[KnappAttack]

Snowdust, real quick,
I've installed a big pump recently, as well as another member on Ty.
I do not have CL or data logging, adj. Fpr, he does. Both of us lost MPG of about 2mpg.
Unfortunately, my short ride of 85miles was heavy on/off throttle. (That's not how I normally ride) my afr was 11.9 to 12.5 which I assume is typical.
He could possibly have a bad O2 sensor?!?! He's looking into it now. He's watching the "poor fuel mileage" thread here.
Just coincidence?!?! Idk. Just letting you know. He is not the type that likes to air dirty laundry.. I can make a copy of all of his Cl, adj. Fpr, etc statements but I think you get the drift. No need to drag others in any further . View attachment 175272

I highly doubt the O2 sensor is at fault, in fact I would guarantee it's the hi-flow fuel pump making for a fuel thirsty machine. Depending on the size of the pump installed, It a fact that the stock fuel regulator can't handle the flow, the pressure is rising and is tanking the fuel mileage. So you put up with it or do a fuel regulator. Just putting in a hi-flow pump is not the right thing to do if you want it done correctly, the regulator needs dealt with for the added flow if the pump is big enough to override the stock regulator. The stock regulator is a bottleneck with a big pump.

The nice thing about an adjustable is you can add a fuel pressure gauge and see the pressure, BUT if its liquid filled, which 98% of them are, you can't trust the gauge 100% anyway, it needs to be vented to atmosphere to be accurate which is an easy fix, there is a plug on the gauge that needs pulled to know the number you are getting is really accurate. I always just pull the plug and get rid of the liquid in the gauge and leave the plug off, this solves the inaccurate pressures you will see with a liquid filled gauge. You can test it by keying on and read the pressure, now hit the gauge with a hair dryer to heat the gauge and key it on again. Without the gauge vented to atmosphere, heat and cold will really change the pressure reading, vent it and no more fluctuations. It's the one key thing people with a liquid filled gauge don't realize, and then start trying to chase the pressure fluctuations.

 

[Doc Harley]

I highly doubt the O2 sensor is at fault, in fact I would guarantee it's the hi-flow fuel pump making for a fuel thirsty machine. Depending on the size of the pump installed, It a fact that the stock fuel regulator can't handle the flow, the pressure is rising and is tanking the fuel mileage. So you put up with it or do a fuel regulator. Just putting in a hi-flow pump is not the right thing to do if you want it done correctly, the regulator needs dealt with for the added flow if the pump is big enough to override the stock regulator. The stock regulator is a bottleneck with a big pump.

The nice thing about an adjustable is you can add a fuel pressure gauge and see the pressure, BUT if its liquid filled, which 98% of them are, you can't trust the gauge 100% anyway, it needs to be vented to atmosphere to be accurate which is an easy fix, there is a plug on the gauge that needs pulled to know the number you are getting is really accurate. I always just pull the plug and get rid of the liquid in the gauge and leave the plug off, this solves the inaccurate pressures you will see with a liquid filled gauge. You can test it by keying on and read the pressure, now hit the gauge with a hair dryer to heat the gauge and key it on again. Without the gauge vented to atmosphere, heat and cold will really change the pressure reading, vent it and no more fluctuations. It's the one key thing people with a liquid filled gauge don't realize, and then start trying to chase the pressure fluctuations.

I read most of your earlier posts on the fuel pressure gauge situation. Very solid work!
He has everything required to dial the sled in, probably needs more time in the tuning process as this just happened.
And yes, that Walbro GSS342 is starving for fuel, or so it would seem. Neither of us thought it could be so thirsty, for the simple fact the computers trying to keep things within a set parameter?!?!

 

[Doc Harley]

Mike, let me rephrase and I'll try to understand.
Stock pump, I run down a logging Trail at 60 MPH maintaining a 12.0 air fuel ratio.
Change the pump out and run down the same Trail holding 12.0 air fuel ratio. Why would I be using more fuel?!?!
Even if you're saying the regulator can't hold the pressure of the new high pressure pump.
Wouldn't the computer signal the injectors to alter the pulse width??

 

[DooZ]

I highly doubt the O2 sensor is at fault, in fact I would guarantee it's the hi-flow fuel pump making for a fuel thirsty machine. Depending on the size of the pump installed, It a fact that the stock fuel regulator can't handle the flow, the pressure is rising and is tanking the fuel mileage. So you put up with it or do a fuel regulator. Just putting in a hi-flow pump is not the right thing to do if you want it done correctly, the regulator needs dealt with for the added flow if the pump is big enough to override the stock regulator. The stock regulator is a bottleneck with a big pump.

The nice thing about an adjustable is you can add a fuel pressure gauge and see the pressure, BUT if its liquid filled, which 98% of them are, you can't trust the gauge 100% anyway, it needs to be vented to atmosphere to be accurate which is an easy fix, there is a plug on the gauge that needs pulled to know the number you are getting is really accurate. I always just pull the plug and get rid of the liquid in the gauge and leave the plug off, this solves the inaccurate pressures you will see with a liquid filled gauge. You can test it by keying on and read the pressure, now hit the gauge with a hair dryer to heat the gauge and key it on again. Without the gauge vented to atmosphere, heat and cold will really change the pressure reading, vent it and no more fluctuations. It's the one key thing people with a liquid filled gauge don't realize, and then start trying to chase the pressure fluctuations.

So is the non-adjustable fpr the answer for these bigger pumps if you don't want to monkey with an adjustable and/or CL? Does CL control the big pump issue?

 

[KnappAttack]

I read most of your earlier posts on the fuel pressure gauge situation. Very solid work!
He has everything required to dial the sled in, probably needs more time in the tuning process as this just happened.
And yes, that Walbro GSS342 is starving for fuel, or so it would seem. Neither of us thought it could be so thirsty, for the simple fact the computers trying to keep things within a set parameter?!?!

Well if I assume he has closed loop, not sure if he does, but if he does, and the stock regulator is used or say the return line is pinched or too small, the Close loop cant overcome the high fuel pressure the mileage will go in the toilet, but it also should be noticeable that its really rich, the logs would show this and his fuel pressure gauge should as well. I've had a pinched return line before that was causing over 70 lbs of fuel pressure at idle to know....

Mike, let me rephrase and I'll try to understand.
Stock pump, I run down a logging Trail at 60 MPH maintaining a 12.0 air fuel ratio.
Change the pump out and run down the same Trail holding 12.0 air fuel ratio. Why would I be using more fuel?!?!
Even if you're saying the regulator can't hold the pressure of the new high pressure pump.
Wouldn't the computer signal the injectors to alter the pulse width??

If all things equal like that there should not be a fuel mileage difference.
What size fuel pump did you install? Perhaps it's not big enough to override the stock regulator.

This is why activating the data logging is invaluable, you can see the entire ride start to finish, and what the A/F is doing rather than just looking at one spot while riding while trying to looking at the gauge in just point it time. It's how I caught my pinched return line and found fuel pressure too high, plus the fact the it transitioned on and off the closed loop it was misfiring it was so rich at that one point so I knew something want proper, but I was at 70 lbs of fuel pressure so imagine that...

 

[KnappAttack]

So is the non-adjustable fpr the answer for these bigger pumps if you don't want to monkey with an adjustable and/or CL? Does CL control the big pump issue?

If you dont want to mess with adjustable reg then yes, it's the answer for the big pumps. Remember when the 17 came out and some guys had poor mileage? The fuel elbow was too small and guys were drilling them out or switching to the larger elbow to fix this. Same thing.... The stock fuel regulator only flows so much before it becomes the bottleneck.

Closed loop will only help with high fuel pressure to a degree depending on how high it is. You will always want your regulator to remain consistent and the only thing that controls the pressure exactly as it should. Putting in a pump that outflows the regulator at any point is going to be a problem period.

 

[sideshowBob]

If you dont want to mess with adjustable reg then yes, it's the answer for the big pumps. Remember when the 17 came out and some guys had poor mileage? The fuel elbow was too small and guys were drilling them out or switching to the larger elbow to fix this. Same thing.... The stock fuel regulator only flows so much before it becomes the bottleneck.

Closed loop will only help with high fuel pressure to a degree depending on how high it is. You will always want your regulator to remain consistent and the only thing that controls the pressure exactly as it should. Putting in a pump that outflows the regulator at any point is going to be a problem period.

Another reason of many that I would like to be able to log fuel pressure as well I would like to be able to log fuel injector duty cycle although the closed loop fuel correction kind of reflects this.
Can't have too much info in my opinion.

 

[Doc Harley]

Looks like I may have to dig into that communion money I've been saving....its tough, especially with rain bearing down on me the last 3 days.

 

[earthling]

Another reason of many that I would like to be able to log fuel pressure as well I would like to be able to log fuel injector duty cycle although the closed loop fuel correction kind of reflects this.
Can't have too much info in my opinion.

If you know rail pressure and injector capacity and duty cycle you can probably graph this out.

 

[fatchance]

Doc, there was no way you would get better fuel economy with the addition of the bigger pump alone. The tunes are running on the rich side to begin with and that was only going to exacerbate the situation. It's very simple, if you saw lower AFR's after the install you were running even richer burning more fuel. The added fuel is to stave off detonation and timing being pulled. I ran the AFPR and BIG pump on the stock tune before flashing and noticed I had to increase fuel to keep AFR's in check and they were very consistent in the mid 12's. It wasn't until I ran the flash which activated closed loop when I could see live as well as the DATA log the AFR's and what closed loop was doing. Then I could see it was pulling fuel and allowing AFR's to climb when cruising, ei: the 60 MPH trail ride. Now we're saving fuel and running efficiently as it was intended.