UPDATE!! 30 April 12

Well, I finally got out to ride yesterday. Me, my wife, and 2 of my girls rode all our machines 46 miles round-trip to the nose of the Knik Glacier near Anchorage. It included 6 river crossings, a little bit of trail riding with some mudholes, and a LOT of long, dusty stretches . We reached speeds up to 45 mph and the machines were dancing across the bumps. It's great to get out again!

:veryhappy::veryhappy::veryhappy:

Weather: 55F and partly sunny, wind about 5 mph.

The good news is the 700 performed flawlessly. Not a single hiccup or any sign of a problem with the machine. Regardless of engine temperature, the idle RPM was pegged at 1180 all day long, which is spot on. The fan was cycling on and off as needed so I know the engine was making some heat under the tank. The point where the problems usually start is when the gauge shows half or less. I ended the day with 2 squares showing on the fuel gauge. That means the tank was really at about 1/8 of a tank.

The bad news is we're not out of the woods yet. Anyone who's been following this thread knows this problem has been somewhat inconsistent. Because of that, I'm not ready to say it's fixed. We will be going out again for 4 days of hard riding over Memorial Day. If the machine performs well over that weekend I'll finally declare victory and call it good.

Stew

 

Having the same problem here too !!

I have a 2006 sportsman 500 EFI doing the same thing. I replace the fuel pump with the Airtex E8198. It ran better but still was stalling a little. Then I saw this forum. So do you think if I get A carter P72118 fuel pump, that it will fix the stalling problem? I already dumped $500 at the dealer and they couldn't fix it. So if there is any that used the airtex and then went to the carter fuel pump and it fixed there issue. Could you please chime in and say it work. thanks

Awesome forum too!!

Any updates from AKStew, if the problem was fixed?

 

I also put the Airtex 8198 in and that's the one I replaced with the Carter after about 3 months. I wish I could say for certain the Carter fixed it but I won't commit until I ride some more.

That said, I chose the Carter because a person on another forum fixed two of his machines with the Carter. He had identical problems and like me, replaced an almost new fuel pump on one of them, though he can't remember the brand. He said he had 2,000 more trouble-free miles before he traded them in.

Stew

 

Thanks for the respond AKStew. When you had the Airtex fuel pump in your machine did it run bad and stall all the time? Because I put in the airtex in my machine and took it out twice and it would run good for a little while and start stalling out both times.

 

Also I saw in your pictures of the fuel pump you pulled out of your tank. That there was a regulator between the pump and the top piece, I do not have a regulator there, Its a straight tube from the pump to the top piece. Is that ok that it doesnt have a regulator there?

 

With the Airtex, my machine ran good until the fuel got too low to be able to keep the pump cooled off. Fuel also acts as a coolant for the pump. I believe the Carter is better in hotter temperatures AND it probably doesn't produce as much heat itself.

YES, you should have a regulator!!!!! Without it, the injectors are receiving fuel at 65-75 psi--almost double what it is supposed be, which is 39 +/- 3 psi. That means you are running really rich because the fuel injector is opened by the ECU for a specified period of time based on inputs from several sensors. The ECU operates expecting a constant pressure with no way to adjust on-the-fly when it's out of specs. More pressure = more fuel passing through during each cycle. This could cause the engine to bog down a bit upon acceleration, which might be what you are experiencing. If you get the regulator I put in a previous post in this thread, it will be OK. I can't say it's causing your specific problems but it sure isn't helping.

If you are missing the housing for the regulator I don't know what to tell you except to look on eBay for a fuel tank or pump assembly.

Stew

 

How did your bike do on your long ride over the Mem Day weekend. looked around to see if you posted anything good or bad but couldn't find any outcome

 

Memorial Day weekend is at the end of next week...

 

AAAK -- Old Timers -- Memorial Day --- Mothers Day both start with an M -- close enuf

 

This is my first post, I just joined today. I've read the entire thread. Thanks for all the good info Stew! I'm extremely curious to see how your fix holds up.

I just bought a used Sportsman 500 EFI and took it out for about an hour today for the first time. I'm a sled guy, this is my first quad. I came on the forum after my ride tonight because I was really upset that my machine ran terrible about 20 minutes into the ride and on the way home it finally died and I had to be towed back by my buddies Honda. My symptoms seem very similar to what has been described.

-Machine has 4800 miles and previous owner claimed to have no problems with it.
-Started easy and idled / ran perfect when I checked it out before purchasing and since when loading on/off trailer at home.
-First ride today - it was warm out around 27'C
-Machine ran great for about 20 minutes. I'm not sure what is defined as "riding hard" because coming from a sled I'm used to hard acceleration and high speed. To me we were taking it easy and riding on flat prairie (no hill climbing) and cruising at around 30-40 mph max.
-I first noticed a slight bog which then turned into hesitation back firing. Then when getting to a road crossing it stalled and was difficult to restart.
-On the way back it suddenly bogged severely and just petered out and died. I could not restart it. Had to get towed back.
-Back at the house I could start it, but it would idle for a few seconds then peter out and die.
-After about 20 minutes I was able to start it and load onto my trailer where it sputtered and died.
-After a 30 minute drive home it started fine, backed off the trailer and idled at 1180 for a few minutes in the garage. Throttle response was fine, no hesitation.

The only trouble shooting I was able to do at my buddies place was pull off the dirty air filter briefly to see if it was starving for air. This had no effect.

To say I'm a little disappointed is an understatement.

Again thanks for all the info - at least you've given me a few items to check. I know the previous owner did point out that he had once replaced the rubber boot around the sensor in the intake because the engine ran poorly. However he claimed replacing the boot solved the problem and it ran great after that. I didn't think to ask when this had happened.

Sounds like the most useful tool a person could use to diagnose this problem is a fuel pressure gauge. I've never used one, how do you use it in order to be able to read the fuel pressure while riding trying to duplicate the problem?

Sorry for the long post. I look forward to your update after more testing!

 

Welcome to the forum but Wow! Not a great first ride. I can see how you would be disappointed.

Sounds like fuel starvation to me.

In no particular order:

Fuel is bad or tank is empty
Tank vent restricted
Fuel lines or injector restricted
Fuel filter plugged
Fuel pump inop or intermittent
Air leak in system
Intake air leak (throttle shaft, intake boot, gasket, or grommet, sensor o-rings)
Throttled body tampered with (especially the TPS)
**Failed sensor or wiring** This is my bet. The manual states that 80% of all EFI problems are wiring related.

Before we get started, answer a few questions if you would.

Did you get a check engine light? If so were you able to check the codes?

How full was the tank when this happened?

How fresh was the gas?

Has Seafoam or other system cleaner been run through it?

Before you do much more I would suggest reading this link to bone up on the pieces and parts of an EFI system and it will help make sense of the rest of this post. http://www.polarisatvforums.com/for...ms.com/forums/atv-repair-maintenance/29632-electronic-fuel-injection-101-a.html

A couple simple things you can do is to make sure the gas is fresh and run a tank of Seafoam through it at about 2 ounces per gallon. Seafoam will clean the pump, lines and injectors. Better yet, if you are comfortable taking it apart, do that and clean the fuel lines and throttle body by hand. Make sure the intake system is snug and in good repair from the airbox through the throttle body to the cylinder head. Check carefully for cracks in the plastirubber (my term). Check the vent lines to the gas tank and make sure they aren't pinched.

Check the IAT and MAP sensors to make sure they are clean of oil or dust. Use MAF sensor cleaner or electrical parts cleaner if you can. They leave no residue and carb cleaner is a little harsher on the plastics and such.

There is a somewhat common problem on the EFI sensor harnesses with wire strands breaking inside the insulation. It looks good to the eye but if you tug on each wire you will feel the insulation stretch more on a bad wire than the others. Polaris makes repair kits for these harnesses.

The fuel pressure tester is a 3' rubber hose with a pressure gauge on one end and valve adapters on the other. It also has a bleed valve for relieving pressure on the system. It screws into the fuel rail. I remove my right knee panel and the gauge actually fits just right on my universal GPS holder.

If you can rent one, make sure it's for EFI and not carburetors. You can buy one for $40-100. Actron makes a pretty good one for a fair price.

Sorry your first ride didn't go so well. Hopefully we can fix it without a lot of money.

Let me know what you come up with.

Stew

 

Wow, thanks for the quick reply! I'll try and provide more information.

Before we get started, answer a few questions if you would.

Did you get a check engine light? If so were you able to check the codes?

No CEL

How full was the tank when this happened

How fresh was the gas??

Unsure, tank was full from previous owner. At least 1 week old. Also unsure if it's regular 87 (which in Canada contains up to 10% ethanol) or premium 91 (no ethanol). I also run premium in my sled to avoid the ethanol. I thought I might drain the tank, put the gas in my truck and fill with fresh fuel.

Has Seafoam or other system cleaner been run through it?

Unsure - I have not.

Additional information. I pulled the spark plug and it looked likw ir could possibly be the original plug! Color was nice uniform tan. So no fouled plug. I replaced it with a new one. Local autoparts store didn't have the NGK but they xref a Champion plug... hope that's OK. I aslo entered diagnostic mode to check for codes etc. I noticed battery voltage was 12.1! That's ~20% charge. My sled is SDI and I know it will run like crap if the battery is weak. I pulled the battery and put it on my intelligent charger. The battery looks old I may need to replace it.

I had planned to replace air & fuel filters. I will check the intake system for cracks and the other suggestions you made regarding the sensors and wire harness.

Thanks again!

 

Battery voltage seems normal to me. Just went out and checked all 3 of my batteries. 11.7, 11.9, & 12.1 after sitting for 5 days. The oldest one had the highest voltage. Given the trouble code you found I don't think the battery is the problem.

It would be extremely rare for the MAP sensor itself to go bad. I think you have a broken wire on the MAP harness. They are very hard to identify so even if you don't find a broken one I would still spend the $30-40 on a new harness for the MAP just to eliminate the possibility. The one here is $34.99, a little more than OEM but built way better.

Only The Best

He also explains the problem in more detail.


Your IAT is dead on. 2.45+/-0.24 would read 2.45 plus or minus .24 ohms. Meaning the reading is good if it's in a range of 2.21-2.69 ohms. I didn't realize that may seem like a strange way to present a specification to some people. I used to be an aircrew member in the Air Force and a lot of aircraft limitations are written that way.

Keep plugging along. As frustrating as troubleshooting electrical issues is, you just have to keep telling yourself you've already saved about $200 in labor so far...at least.

Stew

 

It would be extremely rare for the MAP sensor itself to go bad. I think you have a broken wire on the MAP harness. They are very hard to identify so even if you don't find a broken one I would still spend the $30-40 on a new harness for the MAP just to eliminate the possibility. The one here is $34.99, a little more than OEM but built way better.

Only The Best

He also explains the problem in more detail.

I'm pretty sure I found a broken wire. The +5V wire insulation looked a little "necked" in right at the MAP sensor connector. I unplugged the MAP sensor, turned on the ignition, stuck some multi-meter leads into the COM and +5V terminals and measured 4.98V. Then I grabbed the wire and bent it and tugged on it. Voltage dropped to 0V then back up to 4.98V when I released it. BINGO! Looks like these connectors would be impossible to repair. I'll have to order a harness from the link you provided - thanks!

Once the issue is corrected, will I be able to manually reset the blink code by disconnecting the positive battery lead for 20seconds? So far this hasn't worked, but that may be because I keep throwing the code since the problem hasn't been fixed.

Your IAT is dead on. 2.45+/-0.24 would read 2.45 plus or minus .24 ohms. Meaning the reading is good if it's in a range of 2.21-2.69 ohms. I didn't realize that may seem like a strange way to present a specification to some people. I used to be an aircrew member in the Air Force and a lot of aircraft limitations are written that way.

Sorry if I wasn't clear, but it wasn't the notation that I had a problem with. It was the fact that I was reading 2.45 kilo ohms or 2450 ohms. The service manual says 2.45 ohms. Off by factor of one thousand :gruebel:

Just for kicks, I unplugged the MAP sensor and started up the engine. Idle was horrible and it bogged/backfired when I tried to rev up the engine. Similar to what it was doing the other day.

Now on to the next challenge.... I just noticed that the AWD will NOT disengage. Looks like I'll be pulling the front demand diff and rebuilding. Hope that's not expensive! Grrrrrrr. I very specifically questioned previous owner about the AWD and that everything was working great. At the time I didn't know how to check it. Didn't have jack and stands with me to lift all 4 wheels off the ground.

 

...even though the MAP sensor is primarily for idle quality, it also identifies to the ECU which stroke of the cylinder the engine is on. A faulty/intermittent signal could cause the engine to get out of synchronization causing it not to run and/or make it hard to start.

Stew

 

I don't want to hijack your thread Stew - I could start a new one, but the problems I'm experiencing are relevant to this thread and perhaps furthering the discussion here will benefit others as well.

I used the Sportsman 500 EFI all afternoon yesterday around my in-laws farm. The machine would run absolutely great and then suddenly bog severely and sputter/die. Once this would happen it could not be restarted until it has sat from 15-30 minutes.

By this time I was getting used to the sound the fuel pump would make when initially turning the ignition on. So when the machine would bog and die it became really obvious to me that the sound of the fuel pump was very wrong. Instead of spooling up quickly for 1-2 seconds and shutting off, when I can't start it the sound of the pump is more drawn out and for lack of a better term just sounds like its laboring.

I re-checked battery voltage and even put a charger on it for a few hours, but in all cases it seems that after allowed to cool down for 15-30 minutes, the normal fuel pump priming sound would return and the machine would fire up and run beautifully for another 10 minutes or so until the next episode. After several episodes of this it got to the point where I was able to predict with very high accuracy that the engine would start simply by the tone of the fuel pump when the ignition was turned on.

So so-far 1) I know there's a broken wire in my MAP sensor harness which is causing intermittent problems and 2) I'm beginning to suspect that my fuel pump is acting up.

The other observation I made is that the longer the cool down period, the longer I would be able to ride again before the sputtering death occurred. Especially after sitting overnight, the machine would run well for 30 minutes or longer before a problem. the problem seems to correlate with heat. There is no foil heat shields attached to my fuel tank. I noticed the parts fiche shows two foil shields which attach to the bottom and exhaust side of the tank. Not sure why they aren't there on mine, but on the other hand the machine has 4800 miles on it and I don't see how it got that far without the shields if they were absolutely necessary.

I'm more interested in the idea of replacing the fuel pump alone rather than the entire tank/pump assembly. Is the fuel pump for the 500 the same as the 700? Is the Carter P72118 OK for my 500? - Thanks!

I also ordered that MAP sensor harness from the link you provided above. Good price on the harness, but ouch $25 shipping to Canada!

 

Not hijacking at all. Ouch! on the shipping. I didn't think about you being in Canada.

The Carter pump will work in the 500 as well. I blundered into the weird sound of my pump as well just before I decided on the Carter. I got my automotive stethoscope out and listened to the fuel pump on failed restart attempts. I placed it against the ground wire terminal on top of the fuel pump assembly since that is on top of the mounting post for the fuel pump. My sequence was: Turn key on, wait 2 seconds for priming, turn key to start, sputter a little and die.

Here's how the fuel pump sounded through the stethoscope during the priming sequences on failed starts. It would begin pumping and immediately go down in pitch as if it were creating pressure. Then it would sound as if something let go and was free-spinning until it turned off, after which it would stop slowly instead of cutting off sharply. I must have listened to it about 30 times and every time was the same. During these sequences I had the voltmeter hooked up to the power supply for the pump. It would show about 13v while the pump primed and go down to 5v when priming was done. That's normal.

Next I turned the key to start while listening to the pump. The pump would attempt to spool up and pump for a second or two but then it would just begin to sound as if it were free-spinning and the engine would sputter and die. Another 30 or so tries confirmed this. Voltage was still good…it would start out at 11.9, go up a little, then jump around once the engine began to sputter and die. I don’t think it’s the power supply. The voltage always seemed to react to the engine losing rpms rather than the other way around.

The pump was probably good for years until heating it up repeatedly eventually caught up with it causing it to start failing at a lower temperature. Kind of a vicious cycle: Pump heats up, starts to fail, works harder and produces more heat, which adds to the problem...

Rockauto.com has the Carter pump with strainer sock for around $80 US. That's a good price but I'm not sure about shipping to Canada. NAPA also has them I believe as NFP 72118?

The foil tape I used came from Lowe’s. It’s called Waterproofing Repair Tape and is made by Shurtape. It’s about the size of a roll of duct tape and the package describes it as “foil backed butyl mastic adhesive.” The adhesive is really sticky and as the name implies, waterproof.

Until you get it fixed, you can pour more gas in the tank and that will cool it off to run immediately.

Stew

 

Well I didn't use a stethoscope, but I used the same sequence as you. I would turn the key, wait for the fuel pump to cycle on then off and then attempt to start. On failed start attempts the pump sounded totally different. Lower pitch like it was working way to hard and it seemed to run a second longer than otherwise. I sat there (nowhere else to go but walk home) and every 5 minutes I would turn the key and listen to the pump. Eventually after 15 minutes the pump would sound "normal" and the quad would fire right up.

Is the NAPA pump the same as the Carter (ie. same manufacturer?). I can check their stock since we have a local NAPA store here.

Here's the parts diagram for the 2006 500EFI. Parts 9 & 10 are listed as "Foil-fuel tank". I wonder if this was a later modification because my machine definitely does not have this foil under the tank.

 

That particular NAPA pump and the Carter P72118 pump are the same one. I looked on NAPA and the actual part number is NFP P72118.

#'s 9 & 10 on the diagram are the right foil. The previous owner probably tore it off because it starts to delaminate and come apart after a couple years of getting soaked and dirty. I tore mine off of my 700 a couple years ago, which might have been the mistake that started all my fuel pump problems.

Cheers,
Stew

 

Well I'm going to put the foil back on!

Of course NAPA Canada does not list that part number. Found it on Amazon.com as well, but of course they will not ship to Canada.:motz:

 

Try rockauto.com. I know they ship to Canada.

Stew

 

I called my local NAPA store and they can't get the Carter pump only Airtex E8198 for $155.

I just ordered the P72118 from Rockauto.com for $80 plus $25 shipping to Canada - thanks Stew!

Now I'll just wait for parts to arrive (OTB map sensor harness and fuel pump) then I'll post an update on whether that fixed my problem.

Good luck with your big ride this weekend! Let us know if your machine is fixed.

 

Hello!

I have this problem once! At the beggining I thought that was a wasted injector because of the error that apears on the screen... (i think that was 54). then i try to get information about the price of a new one (around 160 euros :yikes.

with a little pacient I took of the fuel tank and also took off both injectors. It turno out good because the problem was a broken cable of the injector :yahootongue:

it's running now...

 

Stew, any updates after your memorial day weekend ride?

 

Update: 29 May 2012

I think my troubles are over!!

I rode hard for 4 days and not a single hiccup. I purposely kept my gas tank below half the entire weekend. I also pulled a Honda Rancher about 8 miles back to camp with only 2 bars showing on the fuel gauge. We stopped several times at my request to sit a few minutes and let the engine bay heat up. The fan was blowing a good bit but not a single spit or sputter upon restarting hot.

The foil backed butyl mastic tape was awesome as a heat shield on the bottom of the tank. I was a little worried that it might get soft and gooey from the heat but it stayed in place and it's definitely waterproof.

First a very condensed timeline then I'll give my opinion on the cause and solution to the problem:

October 2010 - Machine running good except idling a little wierd. Cleaning the machine I found the under-tank foil peeling off so I just pulled it all off and thought nothing of it. Went on one more ride with no issues before winter set in.

April 2011 - First ride of the year. Ran OK. Idle issue getting worse and had some minor hot restart problems. Wait a few minutes and restarted fine. Replaced fuel pump with Airtex to fix idling and hot restart problems. Didn't yet know I had two separate issues.

May 2001 - Rode 2 different weekends.

First weekend the hot restart went away, but still idling worse and worse. Discovered that Polaris t-bap and throttle position sensor wiring harnesses had issues. Found broken wire on mine so I replaced the t-bap wiring harness and the sensor.

Second weekend the idling problems are still there. Found broken wire on TPS and replaced the TPS because wire was broken too close to sensor to repair. Idling great but hot restart problems re-appear. WTH!! New pump, new sensors and wiring, hot restart still a problem. Check every EFI sensor and associated wiring and all check out good. Still not fixed.

June 2011 - Discovered discussion on another forum about heat related issues and start put foil on the tank and fuel lines. At this point I still don't think it's the fuel pump because it's new.

September 2011 - Hot restart still a major issue. Replaced the fuel pressure regulator with no effect. I had no idea what to do next until I got a response from a member on another forum telling me he had fixed 2 machines like mine with the Carter fuel pump with long-term positive results.

October 2011 - Installed the Carter pump and foil-backed butyl mastic adhesive the night before I leave for a business trip. Get home and can't ride because it's too cold and the snow is flying. Into storage it goes.

Fast forward to today:

I think the initial cause of the spitting, sputtering, hot restart problem is that the OEM fuel pump was almost shot when I pulled the foil off the bottom of my tank in October 2010. I believe it was getting so inefficient it began to run hot, which combined with the engine heat to cause aeration of the fuel in the tank (much like boiling water does from the bottom of a pan). The aeration would have made it impossible for an older, inefficient pump to pick up enough fuel to maintain pressure. Removing what little protection it had just sped up the process and made it fail sooner out on the trail.

When I put the new Airtex pump in, I didn't replace the foil.:dunno: Even so, it worked for a short period of time because it was new. I believe the Airtex pump runs hotter than the OEM pump and like the OEM pump, was combining with the engine heat to once again cause the fuel to aerate. Since the fuel was hotter and less of it was passing through the pump to cool it, the new Airtex failed quickly.

The Carter fuel pump has a different pump mechanism than the Airtex. The Airtex is a spiral design and the Carter uses a gearotor similar to an oil pump. I can't explain the difference except that the Carter design is most likely more efficient causing it to run cooler and not contribute to the heat problem inside the tank. The Airtex is probably a good pump except that it is supposed to be in an automotive fuel tank, far away from any heat source besides itself.

Bottom line: Make sure you have foil on the bottom your tank and the Carter pump is just better where heat is an issue. If you have had foil on the tank and have put in a pump other than the Carter, it should be OK. I just know the Carter is proven to work.

Hopefully that sums it up and I can put this issue to rest.

Stew

 

I think my troubles are over!!
Hopefully that sums it up and I can put this issue to rest.

Stew

Awesome - :veryhappy::slomo::beerchug::biggthumpup::notworthy::goldcup::arms:uttahere:

 

I've been following this from the beginning. Its great to hear that you guys finally have a fix that you can explain and others can go right to for a fix. Thanks for going through all that for the rest of us. Using this thread an Stews how too on changing the fuel pump I finally got up enough nerve to replace the gas tank on my 04.5 700. It was cracked around the filler neck and leaked ever time you got close to full. My gas gage fluttered on and off a few times last winter and then started showing full until it was well below half full and then went dour very fast. I was able to get that to work properly now. I bought a used tank off of ebay. It took longer to take the front fender plastic off (what a pain in the butt) than to take the pump assembly out and change the tank. I did have to transfer the foam and the reflective metal tape from the old tank to the new. The tape came off in pretty much one piece and I used some metal duct tape to secure the edges and extend a reflective surface out over the tank a little farther. I had to order a new sock from Napa for the fuel pump. It took a week and came out of Seattle. All in all using everyones help and experiences it went well. I did tear my front dif out while I had the fenders off to fix a stuck in 4x4 situation but that is another story. Thanks again for all those who passed on there knowledge.

 

That's really great news Stew. Thanks to this thread I found a broken wire on my MAP sensor harness and repaired it with the kit from OTB. I also replaced my fuel pump with the Carter and re-installed new foil heat shields which were missing. I haven't been on a ride yet but I let the engine idle for a good 20 minutes and it ran beautifully without any hiccup. I could feel the radiated heat from the exhaust pipe with my hand right in front of the foil shield. I'm confident the fuel will stay cooler now. The new fuel pump sounds good and strong in contrast to the laboured sound of the OEM pump that was failing.

Thanks again!

 

Stew,
I felt compelled to create a user name on this forum to thank you as well as the gentlemen who first mentioned the carter fuel pump.

A little background on me... I own and operate a noxious weed spraying business in Wyoming and use all Polaris sportsmans, rzr's and rangers. I put anywhere from 3-4 thousand miles a year on my machines. I own 3 sportsman x2 800's all of them everyday suffer from fuel pump exhaustion. I have known this to be the problem for a year and a half now. I was so happy to see your thread and happy that someone chimed in about the carter fuel pumps.

I order three of them today with high hopes they fix my problems!
Thanks again,
Mike
On a side note, my X2 800's all have more than 12,000 miles on them!

 

I also need to ask if anyone has ever fitted a vent tube to the gas cap to try to expel the excess heat. I don't know if this would cause issues of condensation within the tank but I thought I would ask.

 

If I'm not mistaken, I believe the fuel tanks are vented. There should be a vent tube already there on the tank.

 

I will let you guys know how it works for me within the next few days as my machines are running at least 100 miles a day in hot temperatures carrying big loads.