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FIXED!!! 700 Sportsman EFI Spitting, Sputtering, Dying When Ridden Hard

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420K views 272 replies 62 participants last post by  lucas  
#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
 
#156 ·
They do. But the vent and vent tube is tiny. Like either 8thyou inch or quarter inch.
 
#157 ·
More than adequate to vent the tank. Just my thought though.
 
#161 ·
I posted a few weeks back my gratitude to this forum and in particular Stew and the other contributers to this thread for the help they gave me in changing out my cracked gas tank on my 04 700efi(thanks again). I went out Saturday for the first real test ride. I have the ability to leave my yard and staying on gravel back roads or trails along the side of the pavement can go for ever. A couple of my buddies and our boys headed out toward the river and were soon out of the sub divisions and back into the woods. The trails were wet and in places the muskeg holes were deep. Most had some go around and I stayed to those and left the deep holes to my buddies on there Brute Forces. but eventually we got into some stuff were there were no go arounds and I found my self in low and working it hard in and out of holes and around trees and stumps and roots. It was tight slow going and for Alaska was hot at about 75 degrees (I was sweating up a storm in my helmet) and my cooling fan was cycling regularly. We came to a stop to look a hole over and my machine started running ratty and then died. I could start it but I couldn't get it to rev up.We were back in 1/4 mile from the nearest gravel and there was going to be no pulling me out. I was thinking it was going to take a helicopter to lift me out. After letting it sit for a few minutes I tried to start it and it fired off. I had left it in gear and so it took off as I tried revving it up and so I pointed it down the trail and barely made it up and out of the next hole before it started spitting and quit revving up. I came to a stop and let it sit and again the same thing, fired up and get a 100 yards or so and quit. It took me five cycles to make it to a decent trail. once up on top I thought getting it up to speed in high might help. I could go further but die it did. We decided to pull it out and so my buddy hooked on and pulled me 2 or 3 miles out to the nearest road and I was going to get the trailer. It had been about a half hour since I had started it last so I turned it over and it fired right up and purred like a kitten. So down the road I went. I didn't get down on the trail beside the road I kicked it up to 50 down the pavement and it ran great all the way home. Even when we stopped when my Buddy's brute force started knocking. (2 years old and the bottom end is gone). It has run like a champ since. Is this the issue that those of you who had fuel pump problems had? If you let it cool down or keep it up to speed to keep it cool it runs fine but if you let it get worm in tight slow stuff it acts up? Sad part is I had the whole pump assembly in my hands not 2 weeks ago and I put it all back together without changing it. If this sounds like the fuel pump I will be headed to Napa for a Carter fuel pump and start to syc my self up to tear all that plastic off again.
 
#162 · (Edited)
Classic fuel pump symptoms and the story of my life last Summer. Make sure to foil the bottom of the tank as well if you haven't already. While you are at it, I also recommend replacing the little plastic hoses on each side of the regulator with real fuel hose.

By the way, it takes less time to change the pump than to sit and let the machine cool and still have to get towed out.

Stew
 
#163 ·
Stew, again thanks. I went to Napa last night to get a pump and they quoted me $103 plus $30 UPS to ship it from Arkansas. I told him to forget it. Its not the cost of the pump even though that seems higher than others were paying but $30 shipping. Its the size of an aspirin bottle for crap sake. I like to buy local and support the community but when the community starts trying to screw you too. Its bad enough when the lower 48 guys who don't know any better think AK is the other side of the world so shipping must be expensive. But when your own fellow Alaskans are to lazy to ship USPS or even check what UPS ground would be. Well... I'll find one else where. I'm going to check Car quest and Orielly today. If I have to I will have my dad ship one up for $4 in the mail. I'll be sure to change those hoses as well. thanks again.
 
#171 ·
Just an update on my results....

Had the machine out for a 2 hour ride yesterday without any problems. New MAP sensor harness and Carter fuel pump seems to have resolved my rough idle and hot cut-out / stalling issues.
That's good news! Now you can enjoy the ride without wondering when your machine is going to die on you.

As for me, I must have PTSD. Even though I believe mine is fixed, out of habit I still find myself experiencing that low-level, subconscious dread that my machine is going to spit & sputter and die on me at any time. :werd:
Anyone that has had this or a similar problem knows exactly what I'm talking about. :)

Stew
 
#173 ·
06 efi 500 sputtering

Hello Stew,I've been reading your post as I'm wondering if I'm in the same boat,my situation is somewhat similar where as you were having idling issues and shutting down,I am having a miss and or studder with slight back fire at approximately 2850-3000 rpm and only when the machine is hot.Dealer cannot find any codes or issues with electrical,I'm thinking this could be the start of a fuel pump problem.The heat foil is still intact on the tank and the pump sounds normal when cold, but I haven't really listened when hot.Idling issues were taken care of last year with a simple valve agj. but now this has come up.Did your bike miss at a particular rpm? or was it mostly shutting down & hard starting only,thanks for any input. sportsman 2006 500 efi with 2000 miles
 
#174 ·
Hello Stew,I've been reading your post as I'm wondering if I'm in the same boat,my situation is somewhat similar where as you were having idling issues and shutting down,I am having a miss and or studder with slight back fire at approximately 2850-3000 rpm and only when the machine is hot.Dealer cannot find any codes or issues with electrical,I'm thinking this could be the start of a fuel pump problem.The heat foil is still intact on the tank and the pump sounds normal when cold, but I haven't really listened when hot.Idling issues were taken care of last year with a simple valve agj. but now this has come up.Did your bike miss at a particular rpm? or was it mostly shutting down & hard starting only,thanks for any input. sportsman 2006 500 efi with 2000 miles
I'm not Stew but here's my 0.02...

Im confident my rough idling, backfire issues were caused by broken wire in the MAP sensor harness. Harness looked 100%, but when you unplug it and pull on the wires I could see one stretching which indicated the wire was broken inside the insulation.

My fuel pump issue caused sudden cut out when hot and total inability to restart until the pump cooled down (approx. 1/2 hour). When hot the pump definitely sounded like it was laboured and I could tell when it sounded normal again and engine would fire right up.

I believe that a fuel pump issue would show up more as sudden changes in performance - engine cut out or sudden stall and no re-start. The MAP sensor won't necessarily shut down the engine, but seems to contribute to the rough running and backfiring symptoms.

Kevin
 
#176 ·
thanks for the input,just got back from picking up the quad,talked to the mechanic who ran the diagnostics he said at 2850 there is a definite stumble when it's hot,put it on the computer and the stumble disappears unplugs it and it returns,checked all sensors and fuel pressures says everything is within range,he's as stumped as I am.There were no stored codes in the ecu when I took it in.low or high rpm it runs fine and strong,they recommend to drive it until it either gets a code or breaks down,not really what I would like to have happen,so for now I'm going to look into the map wiring harness.Thanks again I will keep you posted
 
#177 ·
thanks for the input,just got back from picking up the quad,talked to the mechanic who ran the diagnostics he said at 2850 there is a definite stumble when it's hot,put it on the computer and the stumble disappears unplugs it and it returns,checked all sensors and fuel pressures says everything is within range,he's as stumped as I am.There were no stored codes in the ecu when I took it in.low or high rpm it runs fine and strong,they recommend to drive it until it either gets a code or breaks down,not really what I would like to have happen,so for now I'm going to look into the map wiring harness.Thanks again I will keep you posted
^^^^
:lame:

Well, there's more to being a mechanic than hooking up a computer. Hopefully he's just bound by Polaris procedures and can't speculate.

I would do as you say and check the wires on the MAP and TPS. Let us know what you find and good luck.

Stew
 
#178 ·
I agree 110%,it is sad that newer mechanics only know what the computer tells them,not that it's a a bad thing,but trouble shooting only goes as far as the equipment allows,part re placers would be a better term for today's mechanic,and I don't mean this in a bad way
 
#180 ·
After posting re: similiar symptoms, I am going to by some insulator, but wondering what type you might reccomend and if I have to remove tank to insulate. Lastly, I have had this 500 for over two years before this started happening. Is this a result in the increase in ethanol in fuel lately resulting in faster fuel temperture due to increase in alcohol content in fuel nowadays? Thoughts?
 
#181 ·
Up here around Fairbanks we don't have any ethanol in the fuel. Not many corn fields or Interstate highways to ship it in. A full (kinda) pipeline of oil runs 1/2 mile from the refinery. I'm still having issues with the fuel pump heating up and causing shut down and poor running. I think as Stew has discovered that as the fuel pumps get old they heat and as the volume of gas goes down in the tank the temperature of the gas goes up and boils and vapor locks the pump. Fill the tank back up with cooler gas and things work for a while. I'm sure reflecting as much heat from the exhaust away from the tank as possible will help but for 8 years mine worked just fine with the factory reflective tape. I'm still waiting to find time to tear off the plastics and put my new pump in. Hopefully this weekend.
 
#182 ·
Not being a mechanic, I am reluctant to visit the dealer to change out pump, but when I do, will have them insulate tank as well. I love to build (construction), but do not trust myself enough to be a DIY Mechanic. Thanks for the insight on fuel and age of pump being an issue. Stay Warm Winter is coming...
 
#183 ·
Thanks. Staying warm has been a constant thought on my mind as I have spent most of the summer on and off getting my firewood put away for the winter. A pipe line 21/2 miles from my house and a refinery 2 miles from my house doesn't seem to help the price of heating oil any.You think it would, go figure. $3.81 a gallon when I filled the tanks last week. But I digress.

A big point Stew made with this post is the fact that you can replace only the fuel pump (about $86) and not the entire fuel pump and guage assembly ($500 +) that Polaris will sell you. They do not sell just the pump. The hardest part of changing the pump on my 04 is taking off the plastic to get to the tank. The newer machines have an easier time of getting the plastic off and access to the tank. Stew gave step by step instructions to get into the tank and replace just the pump. It really isn't hard. I replaced a cracked tank 2 weeks before mine first acted up. I had it all apart and even thought about just replacing the pump while I was there but didn't because it had never acted up. Oh well.
 
#185 ·
great read

wow stew you did a lot of work and my hat goes off to you , I have a 05 700 efi that was stalling out when hot , replaced fuel pump rewrapped my tank and built a heat shield . went out last weekend for a 50 km ride some big hills with slow climb as road was deactivated ran great , thanks for all who had input on this thread.here are some pics of the shield one from the side one from through the fuel tank spot . after loading up on the trailer the shield was not even hot .also replaced the exaust doughnuts the front was shot . :)


 
#186 ·
I'm having the same problems with my 2012 big boss 6x6 where did you find the different fuel pumps are they automotive parts? I have had mine back to the dealer twice the last time they replaced the tps so if that don't work I may try the insulation that makes perfect sense to me since it only acts up after climbing hard was yours also fouling the plugs?
Thanks for posting
 
#187 ·
As new as your machine is I would keep taking it to the dealer until they make it right. I think if you are fouling plugs that your problem is different than the fuel pump issue in this thread. The fuel pump getting hot and the exhaust helping to make the fuel hot causes it to boil and vapor lock which starves the engine for fuel. If you are fouling plugs that is an indication of to much fuel which is a carburetor issue or if you have fuel injection then a bad sensor somewhere or a faulty injector. I'm not sure the fuel pump or even insulating the gas tank would help your situation. I found that my tank had to be below about 2/3rds before it started to act up. when it did I would top it off with cool gas and it would stop acting up until the tank went down and I was once again working it hard. Good luck and let us know when you find out what it is.
 
#188 ·
I found this trhead back a month or so ago. I made the following changed: new plugs, plug wires, fuel filter, insulated tank. It has been working fine but it has only been ridden for short rides. Yesterday, after about 10 minutes of just riding around and goofing off, it started up again. It looks like I am going to be trying the fule pump. By the way, mine is a 2005 700 EFI. More later. Thanks for your help.
 
#190 ·
I have an 06 500 EFI and had problems with it dying for several years. Read the posts and put in the Carter pump, insulated the tank and have run it in the deserts of NM for about 1200 miles and no problems. I do hear a different whine to the pump when it is getting hot. I ran the 500 for 8000 miles before putting in the new pump. I had a service manual to help in the teardown, but was not hard to do. NMDesert
 
#191 ·
I got my Carter pump at NAPA. They had to order it. But it has worked just fine. I carried a long stemed cooking thermometer with me and when it would quit, I would take the temperature of the fuel. It seemed when it got higher than 125 F. was when it would sputter and die. Waiting about 10 minutes or putting cooler fuel in would let it start and run. NMDesert
 
#192 ·
Another good source for the pump is rockauto.com

Stew
 
#194 ·
#196 ·
I think it's fixed the dealer replaced the tps and I rode every day for a week before fouling the plugs again then the dealer found the tps wires shorted to the frame after about 25 miles it seems to be running great no 1/4 throttle sputter of over fueling fingers crossed thanks to every one that replied
 
#198 ·
My 06 500, it already has foil on it , did you put the new foil over what's already on the tank?