Have a 2007 sportsman 800 and checked compression that showed 80 psi dead even both cylinders. I know that's low by reading some forms, but even? is that normal? wonder if I should check again. Test was done cold with airbox off and no throttle

 

Way low. 150-200 psi according to the manual. Wide open on the throttle and check again,but if still low, time to at least replace the pistons. Plated bores,can't bore them out. You really need to check the cylinder clearances to see if a new piston set will solve it or not. Manual goes into great detail on this.2007 Polaris Sportsman 800 EFI Service Manual PDF Download

 

The reading was 180 psi dead even, my bad. Is that ok? What should it be? Also the plug wire boots that go on the spark plugs....mine don't seem to snap on like other wire sets, is this normal?

 

Nothing wrong with 180 psi. In fact very good. Plug wires or boots possibly changed? Are you the original owner? Plus look at the inside of the boots. Could be part of an old cap off a plug or the inner brass part may need to be compressed a little for a better fit.

 

Have wires on order , and no i'm not the original owner. Inside the boots the brass connection seems to be a little to deep and barely touching. Always ran a little off on idle (not strong) did the fuel filter and cleaned the injectors. Now it won't start, pretty sure it the plug wires, used quick start and it doesn't catch at all. They must have just been making a connection before.
Cleaned ground connections , coil connections and ecu connections with electrical grease.

 

Checked fuel pressure along with the fuel filter replacement and injectors? Plus sticking in the boot against the cylinder the plugs should at least have spark. You might look over that cheap 5 buck manual at it's trouble shooting guides and checks. Can pay for itself first time you use it.

 

Good idea , I don,t have one but will borrow one and test. I have the time dealer will be a week getting in wires.

 

So went poking around and found plugs fouled wet (black). Tested plugs and they looked to have great spark, so the plug wires work. Pulled the fuel pump and nothing obvious but will still have to check pressure when I get a gauge. Seems odd to have spark, compression and fuel? any other things I should check?
Things I noted: plugs fouled wet and black
battery tests weak on tester and weak on charge but turns over
small flames out throttle body when turning over Once and a while
been sitting all winter and was running, just idle was low and weak and needed throttle when started
didn't start then cleaned injectors on bench then did start first time (ran great) and after sitting hard to start, had injectors cleaned at shop and tested ok. now won't start

something electrical that I am moving while getting in there?

 

Read this on problems on the 700/800 efi machines. Applies to all efi machines.https://atvconnection.com/forums/pol...ap-wiring.html Check the connectors and thin wiring on the tbap and tps sensors for any bare or soft feeling wires that may have melted internally. If you can rule out a fuel or mechanical problem and even if you have spark, a problem in either of these wiring harnesses can give you fits.You can even ohm out the wires to the connectors,but if the pins pull out just a little they can screw up the sensors input to the ecu. Like the manual says 85% of efi problems are wiring related. I'd still check fuel pressure just to eliminate it,then if it passes I'd check into the wiring. Polaris has crappy wire harness kits that fail over and over,but from the sticky posts OTB https://otbpowersports.com/products/ came out with stronger wiring and connectors.Wish I had those when I was repairing wiring harnesses.Plus codes may or may not be thrown which makes it even more frustrating.

 

ok got plug wires and that didn't work, so going to get fuel pressure tester. Online there are a few fuel pumps (aftermarket) is there a preferred brand?
Checked T-bap harness and all looks good, so will check tps also.
Just a shot...do you know how much antifreeze in a 2010 rush 600?