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Discussion Starter #1 (Edited)
EDIT 6-6-2012: The conclusions in the bottom of this post are incorrect. If you want to read this post and see what my final conclusion is then go to post #148 in the link below. I recommend you read the entire thread if you can because there is a lot of good information to be had that may solve other problems (or make you think you have one :) ). http://www.polarisatvforums.com/forums/199476-post148.html

In the interest of getting all the symptoms and attempted fixes into one thread I thought I'd share about how I spent the whole summer chasing down and fixing a spitting, sputtering, quitting-while-hot issue on my '06 700 EFI. I know this is very long but I think it will be helpful to those of you that have the same symptoms.

Symptoms:
Rough idling
backfiring
hard starting when cold
cutting out when throttling up
dying after a hard run
POOR gas mileage

It started this Spring with the symptoms above. Other than rough idling and the idle RPMs seemed low; the machine would go for hours and then all of sudden it would start doing the funky chicken like it was starved for fuel. I would wait about 15-20 minutes, start it right up, and all would be well again for the next day or two.

Later I did some reading on this and other forums and found several possibilities that could cause the same symptoms: Temperature-Barometric Pressure sensor wiring broken, the sensor itself is bad, the Throttle Position Sensor is bad, its wiring broken, the fuel pump going bad, and hot gas in the tank.

I started with the simple things. I removed and cleaned the T-BAP sensor, fuel tank, fuel lines, fuel rail, and the throttle body. l also replaced the fuel filter and burned a whole tank of fuel treated with Sea Foam. Finally, when I put it back together I double checked all of the connections/clamps from the air box to the intake manifold. None of that fixed the problems.

I decided it was probably the fuel pump. I got the part number from a forum for JUST the pump without the whole friggin' tank assembly, installed it, and called it good...so I thought.

The next trip it worked fine the first day and then BAM! it happened again. Only this time there was no starting it back up so I had to suffer the shame of letting a Honda pull me 8 miles back to camp. I came back to the forums and this time I settled on the T-BAP sensor wiring harness after finding one of the wires to be broken on the inside of the insulation. I ordered a replacement from Only The Best Powersports, installed it, and you guessed it--more ridicule from my Honda friend and back to the forums.

Knowing the wiring was good I went ahead and replaced the T-BAP senor itself. Went riding again, died again, Honda towed me back again. In an unrelated issue, the Gear Position Indicator Switch went south and I had to replace that as well.

Now I turned my attention to the TPS. From the forums, I was able to learn how to check and adjust it--without the special tool and harness from Polaris. The idle voltage was a little low. I adjusted it and started the machine only to hear it keep idling like poo. I had no idea what to do until I pushed on the rubber boot between the air box and the throttle body. When I pushed on it a certain way it purred like a kitten.

I began poking around and as it turns out, there was also a wire broken in the pigtail right where it came out of the TPS. Just like the T-BAP, the insulation was still good but the strands were broken inside (I dissected it later and found it). There wasn't enough wire to work with to splice it back together so I had to replace the sensor.

Fixed, right? Wrong. It died on me the next ride but I was able to restart it after it cooled off again and get back to camp.

During my forum reading, I kept coming across threads that talked about the gas in the fuel tank getting too hot from the exhaust manifold/header and causing the fuel to boil. I dismissed this notion as I thought there was no way gas could boil in the tank without exploding.

Completely baffled, I reluctantly bought a 12" x 12" sheet of insulating foil from NAPA and covered the bottom of the gas tank

I've ridden it hard, really hard, 3 times for several hours each trip now and it runs perfectly. I don't admit it very often but I was wrong. Gas can get too hot and overheat your fuel pump, causing a significant drop in output.

All the other sensor and wiring issues were there too, but I believe it was just coincidence that they all happened at or near the same time. They would definitely cause poor gas mileage and rough idling; however; I think the primary problem causing it to die on me after some hard riding was hot gas in my fuel tank.

Here's what I think fixed the individual issues:

Fuel pump - Nothing. The old one was probably fine.

T-BAP sensor - fixed nothing. These things rarely go bad--no moving parts.

T-BAP Wiring harness - with the correct signal getting to the ECU, this fixed backfiring poor gas mileage, hard cold start and rough idle.

TPS sensor - mechanically, the sensor was probably good but I had to replace it because of where the wire was broken. Fixed backfiring, rough idling, hard starting when cold, cutting out when throttling up, POOR gas mileage.

Foil - prevented gas tank from warming up and overheating the fuel pump. Hasn't died since.

Stew
 

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Discussion Starter #3
Might have to get me some insulation cause I've replaced the pump and it still sputters when it gets hot.
I also put a piece of insulation on the TPS to block the heat from the exhaust pipe that runs just beneath it. Don't know that it was really necessary but it gave me peace of mind.
 

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GOOD JOB!!!

Thanks for posting up so others can benefit form the experience!!!

CW
 

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Thanks for the post Stew. The alcohol content of today's fuel causes all sorts of problems. It lowers the boiling point, decreases mpg, corrodes fuel system components, shortens engine life and drives up food prices. The idiots in DC apparently consider all this to be a good thing. The trouble is, they are wanting to increase the % of alcohol even more.
 

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I'm experiencing close the same problems about the sputtering and rough running. Feel like pulling my hair out. I have no CE light, replaced the coil, plugs, wires, battery, checked TPS wiring (ok, no breaks), checked TBAP wiring (ok, no breaks) and am not sure what else to do. Machine starts right up, but runs like the choke is left on (but its an EFI) and will continue running only if you are on the throttle. Grrr.

AKStew, did you have any Check Engine lights throughout any of this?
 

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I'm experiencing close the same problems about the sputtering and rough running. Feel like pulling my hair out. I have no CE light, replaced the coil, plugs, wires, battery, checked TPS wiring (OK, no breaks), checked TBAP wiring (OK, no breaks) and am not sure what else to do. Machine starts right up, but runs like the choke is left on (but its an EFI) and will continue running only if you are on the throttle. Grrr.

AKStew, did you have any Check Engine lights throughout any of this?
WELCOME BISON!!

Have you checked the adjustment of your throttle cable? If misadjusted it will not idle..

Also wiring problems at the TBAP are many times INVISABLE!! Mine was...

CW
 

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Cant't thank you enough for this post. My 04 700 starts and runs fine until... Who knows. Sometimes if I stop along the trail for a minute, when I restart it idles slow and rough. Whenever I try to give throttle to rev it up, it dies. Waiting about 2 minutes (truly not very long at all) it will restart and run just fine. Then seems to run beautifully. I haven't been greatly concerned because the wait to get it working again is soooo short. But I may have to try your trick and see if it stops this problem all together.
 

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Discussion Starter #10
Cant't thank you enough for this post. My 04 700 starts and runs fine until... Who knows. Sometimes if I stop along the trail for a minute, when I restart it idles slow and rough. Whenever I try to give throttle to rev it up, it dies. Waiting about 2 minutes (truly not very long at all) it will restart and run just fine. Then seems to run beautifully. I haven't been greatly concerned because the wait to get it working again is soooo short. But I may have to try your trick and see if it stops this problem all together.
You're welcome, but I started a later thread that said my particular issue wasn't fixed.

Your problem sounds like the early stages of mine.

Since I posted this I have found poorly seated plug boots (my fault) and plug wires that were almost chafed through to the core. I fixed those and thought I had it licked...NOT! It still dies for no reason.

Now I'm moving on to the fuel pressure regulator. I'm about to post a new thread about it.

Stew
 

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Cant't thank you enough for this post. My 04 700 starts and runs fine until... Who knows. Sometimes if I stop along the trail for a minute, when I restart it idles slow and rough. Whenever I try to give throttle to rev it up, it dies. Waiting about 2 minutes (truly not very long at all) it will restart and run just fine. Then seems to run beautifully. I haven't been greatly concerned because the wait to get it working again is soooo short. But I may have to try your trick and see if it stops this problem all together.
You're welcome, but I started a later thread that said my particular issue wasn't fixed.

Your problem sounds like the early stages of mine.

Since I posted this I have found poorly seated plug boots (my fault) and plug wires that were almost chafed through to the core. I fixed those and thought I had it licked...NOT! It still dies for no reason.

Now I'm moving on to the fuel pressure regulator. I'm about to post a new thread about it.

Stew
I read that post.. why dont you post links so the threads can be researched together... You know that one here and this one there...Just an idea.

CW
 

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Discussion Starter #12
I read that post.. why dont you post links so the threads can be researched together... You know that one here and this one there...Just an idea.

CW
You're Right! Here goes.

Good evening all,
I've written several threads about my saga this summer with my 2006 Sportsman 700 EFI. Since they are all over the place, someone smarter than me suggested I link to the other threads as they contain some useful information. My intent is to post any further updates to my saga in this thread. Replies that pop up in the others will be answered with a link to this one. Here are the links and if you are new to the story, a long update.

Desperate pleas for help and some additional problem areas to look at.
Not Fixed

Hopefully zeroing in on the problem.
Could it be the fuel regulator?

To bring it up to date this is mostly a copy of my post in another forum:

I apologize for the REALLY long post but I’ve been trying to fix this all summer long and there is a lot to tell. Please realize that I’ve searched dozens of forums, read thousands of posts, and taken about 20 pages of notes. Lots of people have the same problem as my machine does but there seems to be no answer.

My real question is whether anyone knows of an aftermarket fuel pressure regulator that will work with the OEM fuel pump assembly…even if the assembly had to be modified.

Here’s why I ask:

It started out the summer with backfiring, rough idle and hard starting. That problem was fixed with a new t-bap wiring harness and a new throttle position sensor and harness. Meanwhile another problem started up but was masked by the initial problems in the beginning of the summer.

Now my machine will run great for hours--and sometimes days--and then just die for no reason. Any RPM, any speed, it just dies--no rhyme or reason as to dry trail, wet trail, mud bog, hot weather, cold weather.

Another scenario is it will be running fine when I shut it off; and then when I go to start it again, it will fire up to normal idle RPM, run for a few seconds, and slowly trail off until it dies.

The rest is the always the same. If I try to restart it immediately it will seem normal for a second or two then die again. If I continue to try to restart it every minute or two, it runs longer with each subsequent restart, until finally it will run fine (minutes or days--who knows). It usually takes about 30 minutes to an hour for it to restart and run normally. It throws no trouble codes when it dies and the speedo is not flashing HOT either. The fan is cycling on and off when it needs to.

Sound familiar to anyone?

To date, this is what I’ve done to the machine this summer:

I've changed the fuel pump and filter sock inside the gas tank, and the voltage to the pump is good. I dismantled the entire fuel system, cleaned out the gas tank, gas lines and fuel rail, changed the filter and burned a tank of gas treated with Sea Foam. The fuel tank vent is also good. I've also covered the bottom of the gas tank with foil insulation.

The air filter is clean and the rubber intake boot between the air filter box and the throttle body is not cracked or rubbed through. The plastic throttle body adapter tube to the head is also in good condition. The clamps are tight in all the right places. The oil is clean and full as are all the other lubricants.

I’ve changed the t-bap sensor, installed the beefier harness (the original was broken on the inside), changed the TPS (which was bad and I thought would be the final solution), and adjusted the TPS to within a thousandth of a volt of factory specs (zero offset and idle voltage). The TPS output reads good at the ECU plug as well. Spark plugs are in good condition and the coil and the spark plug wires are new.

I’ve removed and cleaned the contacts on the power and fan relays and their sockets (they were only slightly dirty but seemed to be making good contact). The fan works as advertised. The resistance at the coolant temperature sensor and the crankshaft position sensor are reading within specs at the ECU plug.

I’ve checked continuity for every circuit related to the EFI and found nothing out of order, though that doesn't mean there's not a short somewhere after she gets warmed up. The battery is strong and reads 12.8 volts. The machine reads 13.8-14.1 volts at idle.

That brings us to the 24th of September when I thought I had it licked.

This weekend when it died again, I jumped off and hit the fuel pressure relief valve and got barely a dribble of fuel. The pump runs fine but I noticed it sounds different when the engine dies. Under normal circumstances, when I turn the key on it will usually run for 2 seconds and cut off sharply like there's real pressure forcing it to stop spinning, and this is as it should be. I noticed when it died, I would turn the key on, the pump would run for its usual 2 seconds, and slowly wind down as if there were no backpressure to stop the impeller from spinning.

I'm convinced the fuel pressure bypass regulator inside the tank is sticking open and dumping fuel from the pump right back into the tank instead of through the fuel lines, which causes fuel pressure to drop drastically and stalls the engine. My first bet is a shoddy valve, but because it starts up again after cooling off I believe it could also be heat related...or a combination of both. The other common symptom is it usually happens after riding for awhile, which would be about the time the fuel level has dropped below the level of the regulator.

It's just a theory, but it makes sense because I've read dozens of threads that describe the same symptoms/scenario: Engine dies when warm for no reason then starts back up and runs fine after cooling down. Nearly everybody tries to fix the problem with a new, aftermarket fuel pump but it rarely ever fixes it; however when people throw in the towel and buy the $500 tank assembly from the dealer, they say it works fine. The only other part inside besides the gas gauge sender is the fuel pressure bypass regulator. That leads me to believe that it's not the pump but the regulator that's the problem.

Oddly enough, nobody on dozens of forums I’ve read has found a replacement regulator to see if replacing it by itself might fix the problem.

That's it for the update.
 

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Discussion Starter #13
Last night, I completely dismantled the fuel system again. The tank had a trace of dirt in the bottom but nothing out of the ordinary. The filter, fuel rail and fuel lines were spotless as were the tiny little filter screens in the intake end of the injectors. The injector spray nozzles were clean as well. I also hooked up the 3-month old Airtex E8198 to its power supply outside of the tank and applied power to it for a few seconds. It ran like a banshee. Though it's possible, I don't think it's already bad. Voltage to the pump checks good when checked according to the service manual.

I got the regulator out of the fuel pump assembly everything is still intact. I couldn't see into it very well but I didn't see anything obviously bad.

There was a little red piece of plastic in the open side where the spring is. It looked like a curly-q from drilling through plastic. Coincidentally, my machine is red. Anyhow, I don't think it was causing any problems and it came right out when I blew into it.

Once I got the plastic out I pushed in on the plunger through the overflow outlet. It traveled to the overflow (dump fuel back into the tank ) position just fine. when I released it, it stuck open for a split second and then released back into the closed position.

I did this several times and it always hesitated long enough for me to get my tool out of the way before it snapped closed. I'm thinking I have a bad regulator.

Since the regulator sticks a bit when I push it in, I think the regulator gets stuck out on the trail, only more so. I think the pressure comes back when the regulator decides to let go and release back to the closed position.

Stew
 

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Discussion Starter #14 (Edited)
I think I found an aftermarket fuel pressure regulator. Pix below.

The first photo is the OEM regulator and the second is a replacement I found at NAPA. As you can see, the NAPA regulator doesn't have the filter screen but compensates for the spacing by adding height to the main barrel and adding a little shoulder on the bypass port for the small o-ring to rest on. Having no filter screen doesn't concern me because when I removed the OEM regulator, I didn't find any dirt inside.

The OEM doesn't have a vacuum port like the replacement. In the absence of a vacuum hose, the regulator will simply reference the atmosphere which is constant. Constant atmospheric pressure equals constant fuel pressure at the regulator's specified psi...in this case 39 psi.

All the diameters are the same except that the mounting flange (the part that is the largest diameter) on the replacement regulator is 1mm less than the OEM. Being smaller is not a problem; being larger might be an issue.

NAPA isn't the only one to carry it. I went there just to get my hands on one and take some measurements. NAPA wanted $84 dollars so I ordered the Standard Motor Products part# PR210 off of eBay for $38.99 delivered. Standard Motor Products is the manufacturer for most of the other brands.

NAPA part# 219679 Echlin
O'Reilly's part# BWD 23020 Borg Warner

Again, go to any auto parts website and drill down to a 1996 Jeep Grand Cherokee fuel pressure regulator.

When I install mine I plan to do a tutorial with pix. I will explain how to check/fix the gas gauge sender as well.

Stew

OEM


Potential Replacement
 

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Excellent detective work man!!

I too have found little red curly ques in strange places on my machine as well... (Mine is red too)

CW
 

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I'm interested in hearing how this pans out. My 06 800 will occasionally quit and have to be restarted right after initial start up but usually only after sitting for a while. I figured it was just that the fuel had leaked off and got air in the system. Haven't had any problems after I get going though....YET!
 

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Discussion Starter #17 (Edited)
Excellent detective work man!!

CW
Thanks, CW! For the time I spent looking at images of regulators and researching part numbers I probably should have just forked out the $500 for the tank assembly. :dunno:

Others will benefit though, and it's a matter of principle. Polaris left their customers hanging on this one. This part is easily serviceable and Polaris should demand that their fuel pump assembly supplier make the regulator and the pump available individually--nuff said.

Polman500,
I will definitely post results.

Stew
 

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Discussion Starter #18 (Edited)
Someone on another forum has brought up concerns about submersing a regulator with a vacuum port on it because it is usually mounted on the fuel rail. They believe letting gas into the vacuum port side of the diaphragm wil swell up the rubber in the diaphragm and possibly cause problems.

When the regulators are otherwise identical, I personally don't think the manufacturer would make a different diaphragm for submersible versus rail-mounted regulators.

Any thoughts?

Stew
 

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Someone on another forum has brought up concerns about submersing a regulator with a vacuum port on it because it is usually mounted on the fuel rail. They believe letting gas into the vacuum port side of the diaphragm will swell up the rubber in the diaphragm and possibly cause problems.

When the regulators are otherwise identical, I personally don't think the manufacturer would make a different diaphragm for submersible versus rail-mounted regulators.

Any thoughts?

Stew
If its not needed for this application why not simply permanently plug it?
 

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Discussion Starter #20 (Edited)
If its not needed for this application why not simply permanently plug it?
If I do that, wouldn't it prevent the diaphragm from freely moving in and out? I would think so because the fuel pressure would have to work against the air pressure on the opposite side of the diaphragm. Kind of like trying to move the handle on a bicycle pump up and down with the air outlet plugged up.

If keeping gas from getting to the vacuum side of the regulator is imperative, you could route a line from the vacuum port to a place where fuel can't get into that side of the regulator.

It would be pretty easy to make a port through the top of the fuel pump assembly similar to the vent line. Then you could attach the vacuum line to it inside the tank and route the external portion to the headlight pod. You would have a free flow of air and no possibility of gas entering the vacuum port.

Another question is aren't they all rubber or rubber impregnated cloth, and doesn't gas touch them from the fuel chamber side of the regulator?

I'm going to call the manufacturer and see what their engineers think.

Stew
 
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