Fuel Pressure Regulator

[Tomcat]

I just got this bike last week so I am still learning how everything works. From what I have read, this is the fuel pressure regulator. I see it has a fuel hose coming to it and one going back to the tank but can't find a diagram or picture that shows what the uncapped port is supposed to be connected to. I am assuming it should be hooked to a vacuum source to sense fuel requirements but that is just a guess at this point. Can anyone identify this connection for me. Thankyou.

 

Tomcat

 

 

[Ryland3210]

It is the pressure reference that allows the fuel pressure to vary with intake manifold vacuum. There are diagrams showing it connected to the throttle body port shown in your picture. It has no effect on wide open throttle, when the intake manifold pressure is essentially atmospheric. At lower throttle settings, it will slightly lean out the mixture.

 

My Cafe Sport has the fuel pump built into the tank, so it is not connected and inaccessible. I assume (hopelessly optimistically) that the factory tuning takes this into account on my bike. That leaves the question whether your mapping takes the disconnected port into account, or whether it is supposed to be connected.

 

There is a thorough discussion elsewhere in this forum with diagrams. I'll see if I can locate it.

 

If I had the port available, I would love to run a tankful with and without it connected to see if it affected fuel mileage.

 

Good luck with the bike. It's a beauty.

[Ryland3210]

Try this:

 

http://www.v11lemans.com/forums/index.php?...0Port&st=30

[Tomcat]

Thanks for the info. I'm going to try to hook it up and see what happens. It looks like someone has done away with the whole evaporative emissions system on this bike so I assume they figured they didn't need this hooked up for the bike to run well. We'll see what happens when I ride it with this connected. Hopefully tomorrow if the rain lets up. I'll post the results.

 

Thanks again,

Tomcat

[gstallons]

In my little time and experience I have with the V11 it and all pictures I have seen the fitting is just vented to the atmosphere. If anyone has a hose from the factory attached anywhere please chime in..

All fuel injection systems I am familiar with have used the fuel press regulator and vacuum diaghram portion is used to regulate fuel pressure with high manifold vacuum (closed throttle plates) and low man. vacuum (open and the act of opening throttle plates). The lower manifold vacuum uses higher fuel pressure and higher manifold vacuum uses lower fuel pressure. All of these pressure regulators utilize manifold vacuum to operate the regulation of fuel pressure.Since there is no fitting to check fuel pressure we must assume they are going to be OK

In closing I must assume this system only concerns itself with baro or atmospheric pressure.

[Tomcat]

Have been doing a little more investigating since my last post. I found a fairly clear picture of the regulator in a maintenance manual that shows this vent uncapped. I guess the regulator is working from atmospheric pressure after all. I also looked for the ports on my throttle bodies to hook this up to and could find none. There are some bosses cast into them that looked like they could be tapped for this purpose, but they are unused on mine. My fuel line routing is also different from the diagram that Ryland refers to in his reply. My system has a single line that goes from the tank to the pump, then the filter, then the left throttle body, then the right throttle body, then the regulator which ofcourse goes back into the tank. After finding the picture I referred to and reading the last comment, I feel sure that this regulator port is as it should be. The bike seems to run OK so I am going to leave it be unless I find some other reason to think that this configuration is incorrect. Thanks for your comments and advice.

 

Tomcat

[Ryland3210]

Have been doing a little more investigating since my last post. I found a fairly clear picture of the regulator in a maintenance manual that shows this vent uncapped. I guess the regulator is working from atmospheric pressure after all. I also looked for the ports on my throttle bodies to hook this up to and could find none. There are some bosses cast into them that looked like they could be tapped for this purpose, but they are unused on mine. My fuel line routing is also different from the diagram that Ryland refers to in his reply. My system has a single line that goes from the tank to the pump, then the filter, then the left throttle body, then the right throttle body, then the regulator which ofcourse goes back into the tank. After finding the picture I referred to and reading the last comment, I feel sure that this regulator port is as it should be. The bike seems to run OK so I am going to leave it be unless I find some other reason to think that this configuration is incorrect. Thanks for your comments and advice.

 

Tomcat

 

The intake manifold port used for reference pressure is on the flange screwed to the engine in your picture. It's the same one used for synchronizing the throttles. There is a hose connected to it. Whether you connect the regulator reference to it is up to your judgment. The pressure is set to 3 bar, so the intake manifold vacuum, which can approach 3/4 bar or more, can have a significant effect on reducing fuel consumption, especially when decelerating and at part throttle operation.

 

For an idea on MPG, my bike ran at 38 mpg as delivered. Calibrating the TPS and synchronizing the throttle bodies improved it to 42, a considerable improvement, and it is still breaking in, at only 4500 miles. This will give you a ballpark idea of how efficient your bike is, and whether to consider going through valve adjustment, TPS cal and Synch before doing anything else.

[al_roethlisberger]

I've never seen the vent port on the regulator hooked to anything(hose) on a V11 Sport variant.

 

A few years ago, I too looked into if it required(or would benefit) from sensing manifold vacuum, but it seemed this wasn't necessary for our bikes.

 

Al

[Tomcat]

I've hooked it up to the cylinder vacuum ports for now. Haven't noticed a difference so far but I really haven't had the bike long enough to say. I think I'll run it this way for a few tankfuls and then uncap it and do the same. I'll post the results. Thanks for all the input.

 

Tomcat

[Ryland3210]

I've hooked it up to the cylinder vacuum ports for now. Haven't noticed a difference so far but I really haven't had the bike long enough to say. I think I'll run it this way for a few tankfuls and then uncap it and do the same. I'll post the results. Thanks for all the input.

 

Tomcat

 

Great!

 

It's a bit of a job on my bike to get the pump/regulator assembly out of the tank and create a leak free port on its mounting flange.

 

If your report shows that it saves any significant gas consumption, now that my bike is out of warrantee, I'll do it and report back as well.

 

If practical, try to use the same brand and grade of fuel and oil throughout, as well as a consistent starting/warmup procedure and tank filling level as well. Avoid doing any tuneup maintenance during the test to keep everything consistent. Sorry if I sound like a schoolteacher!

 

This will be useful information, and if it is conclusive, I'll add the results it to the FAQ section.

[Guest ratchethack]

FWIW, I experimented with this a couple years back by running the air pressure reference on the regulator connected to the RHS intake vacuum barb fitting. I ran it this way for many days on the road. No perceptible difference wotsoever.

 

NOTE: Since the ID of the brass fitting is so minute -- It's the exact diameter of a sewing needle, .030" (I just verified this to make sure I remembered it corretly), I'd concluded it couldn't possibly flow enough air to make any difference in rapid throttle transitions anyway, and due to intake pulse vacuum (lower relative pressure, for Pete's sake ) fluctuations that close to the head, I figured the lack of ability of the .030" to flow significant air makes it useless for anything but a tiny draw of air through the charcoal canister (wot it was designed for), and o' course, balancing the TBs, which it also seems ideally suited for.

 

An interesting follow-on experiment would be to connect the air pressure reference to a barb drilled out to 3 mm or so. NOTE: Please don't do this unless you don't ever expect to use it as a port to balance the TBs again!

 

BAA, TJM, & YMMV

[Ryland3210]

FWIW, I experimented with this a couple years back by running the air pressure reference on the regulator connected to the RHS intake vacuum barb fitting. I ran it this way for many days on the road. No perceptible difference wotsoever.

 

NOTE: Since the ID of the brass fitting is so minute -- It's the exact diameter of a sewing needle, .030" (I just verified this to make sure I remembered it corretly), I'd concluded it couldn't possibly flow enough air to make any difference in rapid throttle transitions anyway, and due to intake pulse vacuum (lower relative pressure, for Pete's sake ) fluctuations that close to the head, I figured the lack of ability of the .030" to flow significant air makes it useless for anything but a tiny draw of air through the charcoal canister (wot it was designed for), and o' course, balancing the TBs, which it also seems ideally suited for.

 

An interesting follow-on experiment would be to connect the air pressure reference to a barb drilled out to 3 mm or so. NOTE: Please don't do this unless you don't ever expect to use it as a port to balance the TBs again!

 

BAA, TJM, & YMMV

 

Ratch, we really need numbers and analysis to determine whether .030" is able to flow enough to affect the regulator, as it appears is intended by the diagrams which show it connected thereto. In terms of circumstantial evidence, when synchronizing with mercury manometers, the columns seem to respond quickly in spite of their mass. I suspect the mass of the regulator diaphragm is a good deal lower. But then, the cannisters are out of the circuit, so the vacuum signal is sensed directly by the manometers, without leakage through the cannister.

 

I checked whether the diagrams showing the regulator connected to the vacuum port have a cannister connected as well. If that's the case, and the cannisters impose a restriction far less than .030, then to that extent the signal to the regulator would be attenuated. At least the diagram in one of the posts shows no cannister connection, just the regulator connected to both TB's.

 

Another question is whether those bikes with the regulator connected also had the .030" restrictors.

 

If bikes with the regulator connected were intended to have no cannister connection which would bleed off the vacuum, and/or have no restriction, but yours has both, that would explain why you saw no difference. Do you have any knowledge of any of these open items?

[Guest ratchethack]

If bikes with the regulator connected were intended to have no cannister connection which would bleed off the vacuum, and/or have no restriction, but yours has both, that would explain why you saw no difference. Do you have any knowledge of any of these open items?

John, my '00 Sport came with a cannister, as did all US issue V11's. It was properly disposed of immediately by the PO. If it was originally connected to the fuel pressure regulator, I wouldn't know. As you point out, if all 3 were connected "as built", it might be credibly assumed that the .030" bore of the intake barbs was specified for this function -- and this function alone -- and not for sole connection to the FPR, which would be eliminating the "attenuating" effect of the canister setup as you point out, thereby forgoing any intended effect at the FPR when directly conneted. The .030" bore was very evidently specified as a "snubber" much as the adjustable idle air bleed screws on the TB were specified, but with much less concern for precision, (with an entirely different function) but where the same kind of precision, let alone adjustability, was apparently neither a requirement, nor a concern of any kind. The lack of any mention in the Service manual (and anywhere else I've ever read on V11 tuning) would tend to support this as something less than important for tuning purposes.

I suspect the mass of the regulator diaphragm is a good deal lower.

A fair enough assumption, but wot of the mass of the regulator valve the diaphragm is attached to?

Ratch, we really need numbers and analysis

John, I respect your motivation in pursuing a comprehensive, detailed analysis, and thorough understanding. However, observing all such things fairly closely, having many times used the barbs for TB balance with a home-made differential manometer, I figure it might reasonably be expected (particularly after the experience of noting ZERO difference on the road directly connected per post above) that if it makes any difference at all to fuel pressure regulation when directly connected, IMHO that difference is almost assuredly so tiny as to be negligible.

 

My precision digital low-flow air flow meter is on the fritz lately , so o' course all of this is a "limited educated assumption" on my part, and I have no documented series of test readings with data or numbers of any kind. Nor have I measured the mass of water in my water manometer to thoroughly understand in exact detail the effects of pressure differentials of both cylinders' low-pressure waves through the manometer. Let's just say that the water in the bottom of the "U" doesn't jump around very much, regardless of RPM. So over-concern about much of anything in this area WRT the importance of the FPR pressure reference quickly tends to fade into indifference for Yours Truly, but o' course, that's just me.

 

If one were interested enough, one might re-connect the removed cannister to both intake barbs and the FPS with a vacuum gauge and take readings on the road at different RPMs and make mileage comparisons in an attempt to reverse-engineer any intent of having the FPS connected. Lacking the original cannister, a similar-sized chamber (an old fuel filter, for example) might serve as a substitute "vacuum attenuator".

 

If there is some effect of having the FPS connected in some way that has a significance to A/F, I reckon connecting it back after having custom and other kinds of maps employed would mean a mandatory re-map to accomodate the FPS.

 

Wot I've posted is the extent of the study I've given this. Frankly, I b'lieve it's a decent tee shot down the fairway beyond wot any such analysis might reasonably be expected to produce that's much of any value.

 

But -- and as aways -- TJM, & YMMV

[dlaing]

Ratch, we really need numbers and analysis to determine whether .030" is able to flow enough to affect the regulator,

No we don't need numbers to know if it affects the regulator, but we need numbers to know how much it affects the regulator.

The restriction of the orifice is minimal.

My balancing meter feels every pulse of the engine.

The only questions are, how meaningful is the effect and more importantly, is the effect beneficial or detrimental?

Ratchet detected no difference, but apparently only used his subjective feel for how it rode.

I am not surprised that it makes no perceptible difference under load.

The greatest engine vacuum is when under deceleration and the lowest when under WOT and load.

I would be very surprised if it does not change the threshold for popping under deceleration, and it would probably change it for the worse because it would run leaner (assuming that is worse, but it could be quite the opposite, depending on the mapping). Assuming that is true, the only benefit being a slight increase in fuel efficiency. How slight a change in fuel consumption is anybodies guess...as you said, we need numbers and analysis.

I suppose you could put a vacuum guage on it, divide the fuel pressure by the vacuum pressure in atmospheres and subtract the result from the fuel pressure at 1 atmosphere to give you a theoretical estimate of the change in fuel flow. Actual flow variation from a change in pressure will offset the answer. But I don't know how to calculate that. I imagine efficiency of flow decreases geometrically as pressure builds, but to what extent, we would need to chart the fuel injectors.

Probably a better way of measuring would be to log the lambda under real riding conditions.

I just got my WBO2 working, finally, but the darn logging is not working right.

eBay buyers beware!

First, the kit was incomplete and I ended up waiting months for the eBayer to not send me the missing part, second, the sensor was bad ($100), third, I needed to re-solder the power supply to the board, and fourth, it logs everything but the bloody lambda!

I should have spent the extra money for a *NEW* LM-1 a long time ago...oh, well.

Anyway, Off to the garage to try to get it working.

The good news is that watching the lambda change, I can see there is huge room for improvement to the map!

EDIT, after either the firmware update, or setting to defaults, or clearing the log, the next log worked like a champ! Next step is to hook up the RPM sensor. I was surprised to find some downhill light throttle action had it running rich. This could be where the hooking up the vacuum to the pressure regulator could pay dividends. Although I am not sure why hooking the vacuum to TBs is any better than mapping.

[raz]

Probably a better way of measuring would be to log the lambda under real riding conditions.

I'm pretty close now. I have written my own datalogger software that will log all data you get from the ECU and the LC-1 as well as GPS data like speed and altitude. Last try I had some stupid Microsoft serial port glitch so my session ended early and I rode for an hour not knowing that.

 

Also, I've tried locating an Y junction for the hoses. Auto dealers are not interested in selling one to me unless I can name a car model that has it . Guzzi parts are unavailable (as in not longer listed at all). I'm actually thinking of getting one from a pet shop, I think one for aquariums air pump stuff will do. It may not be a good long term solution but it should hold long enough for my tests.