Smart valves in gas tank
- Thread starter Mlosey131
- Start date
I did the fix on HCS and it did not fix the problem. I am waiting on warrantied parts. Sled still runs fine but I usually have to put a gallon or two of gas in at the end of the day to safely climb hills.
The whole fuel pick up including the gas gauge should be chit canned. It is junk.
The whole fuel pick up including the gas gauge should be chit canned. It is junk.
My pump is hissing too. Always at the end of the day with 1-3 gallons left.
Did you do the HCS fix?
Mine did the same thing. Dropped it off at the dealer and they said something about replacing or puting springs in the smart valves, sorry can't remember exactly what they said. But whatever they did fixed it, so far. Two rides prior, fuel pump would start whinning at about 30 miles. Look in tank and could clearly see gas in there. Only put in around 7.5 - 8 gallons after each of those rides. Turn off the sled shake it and whine stopped for a bit then start back up again. Both those rides it cutout on me a few times. One ride post fix and not a problem. Put on over 50 miles and didn't hear the pump once and never cutout. Guage still sucks, but that really doesn't bother me. See how it does this weekend. I think that pump will burn up if you let it whine to much.
I tried to find springs but couldn't get the right strength. The ones I found were to stiff and wouldn't allow the smart valve to close at all and I was afraid it would suck air.
Dealer told me that eventually the fuel pump will fail if I am hearing it whine like that.
If I knew where to get the right springs I would just do that to get me through the season then pull the whole assembly this spring. Im scared this thing is going to leave me stranded in the backcountry or cut out when I am climbing a big hill on my out. Its very unnerving at the end of the day.
Dealer told me that eventually the fuel pump will fail if I am hearing it whine like that.
If I knew where to get the right springs I would just do that to get me through the season then pull the whole assembly this spring. Im scared this thing is going to leave me stranded in the backcountry or cut out when I am climbing a big hill on my out. Its very unnerving at the end of the day.
I wondered if this would ever become an issue for more people. Major problem for my sled last year, same symptoms as described above fist the pump starts squeeling like a pig and then sled starts cutting out, always with 2-3 gallons of fuel left in the tank.
I spoke with the engineers at Walbro (who make the smart valves) at length about the issues to see if there is something that can make the smart valves go dumb. In the past, the actual plastic that some of the gas tanks were made out of would react with gas over time and release some plastic residue that would clog the intake screening material on the valves. This was solved with a slightly coarser mesh material and better plastic in the tanks. As far as wear items in the smart valves there really aren't any except the springs. When the fuel gets low and the valves come out of the fuel they close and compresses the spring, so depending on how you ride the valves could cycle a lot each day and sack out those little springs slightly making it hard for the valves to re-open. They are a very low rate spring and hard to find. You might try stretching them slightly as an interim fix.
The other possibility is that you have water in your tank and the valves are working as designed and pulling closed when moisture contacts the water resistant mesh on the valves. I drained my tank several time and never saw any water...
I think the main issue is not with the valves but the design of the system by Cat. The way its plumbed all the fuel has to go through the front valve. Its a small fitting to begin with and makes a 90deg turn inside the front valve, very restrictive. When your going up hill and the front valve comes out of the fuel and closes the pin on top of the diaphragm is sucked up into the 90deg fitting and further restricts the flow from the back two valves. And the front valve then has a hard time re-opening because of the focused suction on the top of the diaphragm inside the fitting going to the rear valves. In theory the valve with the vented diaphragm should be in the rear where cat has it because it will not suck air when going up hill and still prevent the system from becoming vacuum locked. The prescribed fix on HCS to move the vented valve to the front will allow the system to suck more air when going up hill but it allows the front valve to break the vacuum and re-open easier.
The other way to deal with this is plumb in a "t" above the front valve that allows unrestricted flow from the rear valves that doesn't have to go through the small 90deg in the front valve.
Last issue is the valves have a hard time staying on the bottom of the tank because of the plumbing and the rear ones especially can twist and move up the side of the tank from bouncing around. Some low points/depressions molded into the tank and better way to secure the valves would probably help a lot.
I did a T for the rear two valves, stretched out the springs slightly, moved the vented valve to the front, and checked in the tank with a bore scope to make sure the rear valves were flat/ in the correct spot and haven't had an issue since. But this is just one more thing we shouldn't have to do on this sled to make it work
.....
Here is where you can get replacement valves if your in a pinch with an interesting read on the smart valves.
Also if you had a fuel pressure gauge you would see a big drop when the pump starts humming.....not good for the pump OR MOTOR
I spoke with the engineers at Walbro (who make the smart valves) at length about the issues to see if there is something that can make the smart valves go dumb. In the past, the actual plastic that some of the gas tanks were made out of would react with gas over time and release some plastic residue that would clog the intake screening material on the valves. This was solved with a slightly coarser mesh material and better plastic in the tanks. As far as wear items in the smart valves there really aren't any except the springs. When the fuel gets low and the valves come out of the fuel they close and compresses the spring, so depending on how you ride the valves could cycle a lot each day and sack out those little springs slightly making it hard for the valves to re-open. They are a very low rate spring and hard to find. You might try stretching them slightly as an interim fix.
The other possibility is that you have water in your tank and the valves are working as designed and pulling closed when moisture contacts the water resistant mesh on the valves. I drained my tank several time and never saw any water...
I think the main issue is not with the valves but the design of the system by Cat. The way its plumbed all the fuel has to go through the front valve. Its a small fitting to begin with and makes a 90deg turn inside the front valve, very restrictive. When your going up hill and the front valve comes out of the fuel and closes the pin on top of the diaphragm is sucked up into the 90deg fitting and further restricts the flow from the back two valves. And the front valve then has a hard time re-opening because of the focused suction on the top of the diaphragm inside the fitting going to the rear valves. In theory the valve with the vented diaphragm should be in the rear where cat has it because it will not suck air when going up hill and still prevent the system from becoming vacuum locked. The prescribed fix on HCS to move the vented valve to the front will allow the system to suck more air when going up hill but it allows the front valve to break the vacuum and re-open easier.
The other way to deal with this is plumb in a "t" above the front valve that allows unrestricted flow from the rear valves that doesn't have to go through the small 90deg in the front valve.
Last issue is the valves have a hard time staying on the bottom of the tank because of the plumbing and the rear ones especially can twist and move up the side of the tank from bouncing around. Some low points/depressions molded into the tank and better way to secure the valves would probably help a lot.
I did a T for the rear two valves, stretched out the springs slightly, moved the vented valve to the front, and checked in the tank with a bore scope to make sure the rear valves were flat/ in the correct spot and haven't had an issue since. But this is just one more thing we shouldn't have to do on this sled to make it work
.....Here is where you can get replacement valves if your in a pinch with an interesting read on the smart valves.
Also if you had a fuel pressure gauge you would see a big drop when the pump starts humming.....not good for the pump OR MOTOR
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S
splat10
Member
The new springs are tapered (conical, wide at the diaphram side). The dealer can get them, mine did when i had an issue. The problem is the diaphram can walk up the spring then there isn't enough spring pressure to re-open the valves and you're screwed.
This didn't completely fix the problem for me so i just moved the vented disk to the front and we'll see if that helps. i'm going to see if i can hook my fuel pressure gague up and see if it tells me anything. Most of my problems occur at startup / idle. When i go to take off it bogs out and dies. i had the bog before but it never died.
I think the trail tank with the pump in the back might actually be the ideal solution to this problem.
This didn't completely fix the problem for me so i just moved the vented disk to the front and we'll see if that helps. i'm going to see if i can hook my fuel pressure gague up and see if it tells me anything. Most of my problems occur at startup / idle. When i go to take off it bogs out and dies. i had the bog before but it never died.
I think the trail tank with the pump in the back might actually be the ideal solution to this problem.
My understanding is the vented disc should be a different color? Can anyone verify this or help identify. My fuel pick up issues have gotten worse all year. I modified the pick per hcs thread but mine finally quit. Vacuum locks and dies. Let it sit 10 mins it starts up and runs for 10 mins before being starved for fuel and dieing. I am waiting on backordered warranty parts from dealer but sick of waiting!
I
izzni
Well-known member
Vented disc is a definitely a diff color, but hard to see through membrane. Have you tried stretching the springs as well?
No, haven't touched springs.
Are you positive all sleds had a cented disc? I may missed it but I swear all discs were the same color.
Now I am curious and will take it apart again tonight.
Are you positive all sleds had a cented disc? I may missed it but I swear all discs were the same color.
Now I am curious and will take it apart again tonight.
I
izzni
Well-known member
Positive mine had one. Hard to see though unless you pop the mesh membrane off. It will have a little hole in the foam disc underneath. You could always vent it yourself by making a small hole in the vented disc.
G
gjp
Well-known member
My sled had the vented valve on the back (light turquoise color). You have to remove membrane to see it clearly, as izzni stated. I lightly stretched the springs. Be careful when placing the springs back in. I had one stick because it was not properly sitting in the housing. (Test them with several compressions after re-assembly)
I have a 2012 M800SP (early build). Dealer is now warrantying mine too, but I did see an improvement moving the vented to the front and stretching the springs.
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