My polaris has been over fuel ( i think ) for a while now. I took it to a shop and they cleared the fault codes but they were not that interested in looking at the problem. Got the bike home with no fault codes. Went for a quick ride then starts spluttering blowing black smoke. The fault codes 41 and 51 then appeared on the on board dignostic. The bike has compression. the fuel injector ressistance has corrct ressistance. the IAT sensor has been replaced. I have testeted the cables for faults in the wiring harness. Im still thinking of fuel injector or ecm any Ideas? cheers

 

You can throw codes that may not even be related if you have a short on the t-bap or tps connector or wiring harness. Look at the wiring from the t-bap,follow it down to the main harness for any bare spots or soft feeling wires that may have melted internally. Same for the tps wiring harness.Plus the pins in the connectors can pull back a little and cause intermittent or constant problems. Like the service manuals say, 80% of efi problems are wiring or connector related,not the sensors themselves.Look the sticky post in the expert section on 700/800 efi problems. Same for your 500.Most common problem was the tbap harness.Some symptoms of a bad pressure sensor harness(t-bap) are engine will run poorly, no power, poor idle, or engine misfire. Second was the rubber grommet under the t-bap sensor itself that if cracked or split can suck in air and cause problems.Again codes may be thrown or not,plus codes may not be related to the actual fault.As a result of the sticky post on efi problems,better repair kits came about from OTB. A lot better repair harness kits than the ones I installed from Polaris that kept failing. Thin wiring and cheap connectors were the main problem. Look over what otb has to offer as far as harness repair kits.https://otbpowersports.com/products/...ring-harnesses

 

Hi mate.

Thanks for your quick reply. Appreciate your time. Have looked on this site for a while now and seen your detailed posts. I will check over the harness again. I am an electrician but not an auto electrician. I am learning so much working on this machine but it has almost beaten me. Nothing that a bit of patience and perseverance cant resolve. I will look over what you have said. Thanks again old mate!

Kind Regards Sportsmon

 

I hope it's something simple that rears it's ugly head like this guy found. Efi problem can be so frustrating at times..All it takes is for a bare wire to touch the engine or any metal.Plus check the crank position sensor harness that runs under the throttle body. Shorts can happen there also.

 

ive got my cable and crimp set. think im going to re do the cable loom for the iat, map, tps iac and fuel injector. they tested ok but i supposed vibration can change things aswell as heat. Thanks Again

 

ok so since i have previously posted i have checked the t-bap harness, ( wires from the tps, iac iat, ect, map sensor and fuel injector. ) Done a voltage test and continuity for these cables. Also the ressistance checks for parts that were able to be tested. the stator cables were a bit worn under the air box intake manifold but have repaired and checked the crank position sensor cables but looked and tested ok.

I checked for any leaks on the intake manifold by smothering the intake chamber but she stalled with no sign of leaks on the map area or fuel injector O ring. I smothered the exhaust and she still ran with a few leaks. Not sure if that would cause any over fueling issues??

I was a bit suspicious of the fuel injector because that was the first code that came up after resetting it from a polaris dealer. the coil ressistance was spot on but found somewhere on a post online that they are susceptible of shorting from the coil internally to the external metal frame which would cause the fuel injector to stay open due to the negative wire being switched from the computer. ( only found this out by working on this bike!! ) as frustrating as it has been it is nice to know i am learning something.

Unfortunately i live in New Zealand so any replacement parts take a good four to five weeks to arrive so when the parts do arrive i have lost track of any progress.

I have not tried a new injector yet. I had a quote for around $400 from a polaris dealer here in New Zealand so obviously i will get one from ebay or something but alas.

So to sum it up, what have i done to the bike,

Well.....

*Compression test was fine 10 or 20 above perhaps.
*Wiring harnes has been looked over a couple of times now. ( although the connections from the computer have been removed and reconnected that many times now it is possible they have been worn to despare. )
*IAT has been replaced.
*T bap harness checked
*removed the connections to the computer and all fuel injector components and put 250V down the cables to check for insulation break down to all cables and to ground. But tested ok
*Had a Beer !
*Flushed the throttle body with cleaner.
* The coolant fan comes on correctly during operation.
*Had another beer!!! ( perhaps this is where the fault lies...)

* Fuel injector works fine with a 12v supply, opens and closes with each response fine. ( but still not sure )

The bike will start and idle any day of the week no problem. give it some revs and she is blowing that ugly black smoke and smells of petrol instantly. When i clean the carbon fouled plug or replace it the bike wil run sweet for a few minutes.

Items i am thinking of are my connections to the field sensors are still not correct.
The fuel injector
the computer of ecm
or perhaps i have the wrong brand of bike for the country i live in.

Many thanks to all that reply.
Think this site is fantastic !

Cheers Sportsmon.




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From what we experienced at the shop a lot of the time even if the t-bap or tps harness may ohm out ok on the wiring to the connector pins,the pins themselves can pull back a tad and not make contact with the sensors. That's one of the reasons for the otb kits,not just to replace the thin harness wiring but to replace the cheap connectors that Polaris used.Usually the pressure sensor(t-bap) was the faulty one but the tps harness could do the same thing. Again the fault codes that are thrown may not always be the actual problem area.Another section that's faulty may trigger say the iac or injector codes,but they can be thrown as an indirect result. Frustrating at times.