I just bought a nice 2004 Sportsman 700 EFI, 660 miles and about 100hrs. Bought it from an older gentleman who was the original owner, nice looking, clean well taken care of machine but...........

It runs like crap! I have spent the last couple days reading posts about this particular year and the issues with the EFI system. I don't seem to see too many people with my exact problem more like parts and pieces of them. Here is what is going on:

First time I noticed I was seeing what it would do and it wouldn't go over 40mph it felt like it was maxed out is the best way to describe it. After some more riding I noticed it was real sluggish around 30mph or so, at times throttle wide open and no response. On the way home it backfired a little bit also. I'm not sure if this is heat related, the fan is cycling normally.

Most of the issues I have read about seem to include erratic idle and dying and not being able to restart the machine, I have NOT had any of these issues. It just feels like there is a governor on it at times and some sputtering and backfiring I have had it up to 60mph with more to go, so I know it's able to "run normal" at times. If I keep it around 25mph or under there are NO issues, runs perfect. I've only put about 12 miles on it

It starts and idles fine no matter how hot or cold. Also no codes have been thrown. I keep checking but NOTHING showing on codes.

I found out before I bought this machine the T-Bap sensor was replaced at the dealer also the fuel pressure was tested by them and said to be ok.

This is what I have done so far. Checked air filter, checked wiring harness on T-Bap sensor, I have heard there are issues with this but mine is plenty long enough and the wire appears to be larger than 22gauge, the wires coming off of it are white then they splice into the colored wires probably 18" back, appears to be factory and not ever changed, also pulled and tugged on wires appears to be intact and ok, nothing loose.

I have a hunch this machine sat for a long period of time and thinking I should take it apart and clean the fuel system. I know on a carbed bike that is the first thing you would do, not sure on EFI but thinking it's the same concept of gumming up and varnish, especially with the crappy ethanol blend gas we are forced to use out here.

What are your thoughts, ideas on where I should go with this?


Thanks in advance

 

Wouldn't take any ones word on the fuel pressure,I'd check it myself. Must hold 40psi +/- 2psi with no appreciable drop. Doesn't have to be an erratic idle or dying for electrical connectors or the wiring to the sensors to cause problems,but still sounds like what's happening. Also sensor wires can be melted internally,sometimes you can find soft spots in them,plus the pins on the crappy oem connectors themselves can pull out a tad and make erratic contact on the tbap and tps sensor and cause all sorts of running problems.I don't think that we had any injectors varnish up even when sitting up,but I suppose it can happen. If cleaning doesn't help I'd still look into the sensor connectors and harness closer.If they've been replaced with the ones Polaris supplied,they're crappy also.Replaced a bunch of these over and over. If you haven't checked out this place,that's something else you can try.Wish I had them when I was replacing sensor harness kits. Only The Best Plus can't beat a manual especially on a machine new to you that can help trace down problems.2004 Polaris Sportsman 700 EFI Service Manual PDF Download

 

Thanks old polaris tech! I've read many of your replies and was hoping you would chime in on this one.

Tonight I looked at all the wiring and connections for the T-Bap , and TPS. I have to say that everything looks good to me, I am a Journeyman Electrician so I have a pretty good idea of what they should look and feel like, I think so anyhow! The T-Bap harness is spliced so far back, almost under the tank I have to wonder if it hasn't been done a time or two. The splices are soldered and covered with a clear type of heat shrink then they had electrical tape over them. The purple wire from both the T-Bap and TPS are tied together and covered with heat shrink (the black kind with the yellow glue that oozes out)

After I did that I took it out for a test. I let it run for about 5mins then took off. I accelerated up to about 55mph then backed off and came to a slow stop, did this about 6 times in a row and it was perfect, didn't miss a beat! So I started back to the house from a stop and guess what nothing, didn't die but there was NOTHING when I hit the throttle, I honestly thought it was going to leave me there, after doing this for a few minutes I shut it down sat for a few mins then started it and made it home, didn't go very fast, just wanted to get home.

I noticed it seemed to be running pretty hot, may be normal? Hard to say, I could feel the heat coming off the side (right side panel removed) when I shut it off the fan was running I turned the key back to the on position and it wasn't running. My 2000 Sportsman 500 will start the fan again when you turn the key back on, if it's hot.

So I can say based on my testing tonight that it runs good when cold but has issues when it heats up. I will check the fuel pressure, but I'm going to have to find a gauge.
Of course when I test drove it (before I bought it) it was cold so it ran fine. Guess I didn't really notice before because I took it easy when I first rode it.

Going to download that manual right now!

Thanks again!

 

I ordered a T-Bap harness from OTB. I will check the fuel pressure tonight when I get home and verify it's good. Still no codes being thrown either.

What are your thoughts on it running good at first then having issues after warming up? I really have no idea where to go from here.

 

Doesn't matter whether they're hot or cold as issues like this can happen at any time. What makes it more frustrating is that codes don't always appear.Most of the issues we had were the thin brittle wiring and connectors,mainly from the tbap. Didn't have to change out as many tps kits.Sometimes you can isolate an individual harness problem by wiggling it and see if the engine changes,gets better or worse. Like the manual says 80% of efi problems are wiring related.OTB makes a point of this also in their home page.Only The Best Hope that the tbap harness solves the problem.

 

Got a fuel pressure gauge and guess what? No pressure, at first I thought maybe I hooked it up wrong. I tried with and without valve core not running, running.... I can hear it run when I turn key so it's powering up. I verified the gauge was good with air pressure. Is it even possible for it to run with no fuel pressure? I mean the gauge does not move at all. Am I missing something?

 

Test it with it not running.Turn the key on with the gauge hooked up,open the bleeder hose on the gauge then shut it. Sometimes you have to do this a couple times to get any air out so you can get a good reading.

 

Wanted to update this as I got the issue fixed. Not sure what did the trick as I replaced a few things, this is what I did:

New T-Bap sensor wiring harness from OTB Powersports
New Fuel Filter
New Fuel Pump (I went as far as pulling it out so I figured why not)

I recently put a little over 100 miles on it over a weekend and it didn't miss a beat.

Thanks for the help!

 

May have been a combination of all three? Main thing is that's it's up and running. Good luck,hope no more problems for a good long while.

 

I have a 2009 sportsman 800 ho ran fine for a year then one day I jumped on it put it in gear and it started creeping and belt started screaming put a new primary clutch in and still doing the same then someone told me my idle was to high and I don’t know how to adjust it, and why all of the sudden would my idle be high?