Stumped fuel injector ecu issue

[chris05]

Got a 900 Rmk.
Cannot figure this out and neither can my dealer.
I think I ran my sled out of gas last weekend if not I was very close. So being about 1 mile away from the truck we drug it back. Got it home put gas in it can not get it going.

What I have done.
I primed the pump by hooking up power to the fuel pump let it run and made sure there was no air in the fuel rail by bleeding it. The stator is supplying enough power to run the fuel pump but I have left it plugged into the battery anyway. Fuel rail has 60psi. When I try and start the sled it runs for a bout 2 secs if you give it any kind of throttle it immediatly chokes out and dies. However if i just sit and dump gas in the airbox I can run the sled forever if I keep adding gas. So this rules out any spark timing electrical issues as far as that goes. However its very clear the injectors are not firing for some reason. Dealer plugged it into the computer there were no codes and the injectors test good.
So my next step is to try and find out if the ecu is bad or the injectors (dealer reflashed the ecu and it worked fine). The problem with this is I can not find one that I can test with. I have to buy both and they are not returnable to polaris once taken out of the box. And they are $$$. We can find ones for 06 rmk's all over. However mine is an 05 an incompatile due to the 2 injector style of the motor.

Anybody have any ideas? Is my thinking logical?

Thanks

 

[benamen]

Maybe try disconnecting the bottom end of the fuel filter, sticking the end into a container and start up the fuel pump with the battery for a second to see if you are getting any volume through the filter, if not possibly a partially plugged filter?

 

[AKSNOWRIDER]

Got a 900 Rmk.
Cannot figure this out and neither can my dealer.
I think I ran my sled out of gas last weekend if not I was very close. So being about 1 mile away from the truck we drug it back. Got it home put gas in it can not get it going.

What I have done.
I primed the pump by hooking up power to the fuel pump let it run and made sure there was no air in the fuel rail by bleeding it. The stator is supplying enough power to run the fuel pump but I have left it plugged into the battery anyway. Fuel rail has 60psi. When I try and start the sled it runs for a bout 2 secs if you give it any kind of throttle it immediatly chokes out and dies. However if i just sit and dump gas in the airbox I can run the sled forever if I keep adding gas. So this rules out any spark timing electrical issues as far as that goes. However its very clear the injectors are not firing for some reason. Dealer plugged it into the computer there were no codes and the injectors test good.
So my next step is to try and find out if the ecu is bad or the injectors (dealer reflashed the ecu and it worked fine). The problem with this is I can not find one that I can test with. I have to buy both and they are not returnable to polaris once taken out of the box. And they are $$$. We can find ones for 06 rmk's all over. However mine is an 05 an incompatile due to the 2 injector style of the motor.

Anybody have any ideas? Is my thinking logical?

Thanks

dont know if this will work for you..but worth a try...turn off the ignition key and hit the kill switch to the down position..now pull the sled over 5-8 times like your starting it..now turn on the key and raise the kill switch..should fire right up....if it does fire right up what happened is it used all the volts out of the capacitor..(from what I have seen putting battery voltage to the fuel supply jumper wont recharge the capacitor)..so far the only way I have found to recharge the capacitor is to turn off the ignition and pull the sled over..the stator will recharge it......

 

[chris05]

We have just replaced the fuel pump and tank because of the recall. We also replaced the fuel filter and there are not any obstructions between tank and injectors. (lines are clear) The sled also has a brand new stator I put in a few weeks ago because the old one burned out. The sled makes great power. Around 14 volts when running on the gas that I keep dumping in the intake.(lights come on can hear the fuel pump running etc). Even so I still leave the the fuel pump plugged into a battery while trying to run it. Sled will still only run for a few seconds if I dont keep adding gas to the intake. Any other ideas. Thanks for your input so far guys. I am really scratching my head on this one. Makes me wish sleds still had good old fasion carbs.(Easy to diagnose those problems)

Chris

 

[AKSNOWRIDER]

We have just replaced the fuel pump and tank because of the recall. We also replaced the fuel filter and there are not any obstructions between tank and injectors. (lines are clear) The sled also has a brand new stator I put in a few weeks ago because the old one burned out. The sled makes great power. Around 14 volts when running on the gas that I keep dumping in the intake.(lights come on can hear the fuel pump running etc). Even so I still leave the the fuel pump plugged into a battery while trying to run it. Sled will still only run for a few seconds if I dont keep adding gas to the intake. Any other ideas. Thanks for your input so far guys. I am really scratching my head on this one. Makes me wish sleds still had good old fasion carbs.(Easy to diagnose those problems)

Chris

sounds like the fuel pump is wired backwards/running backwards..have you verified fuel pressure?...

 

[chris05]

Yes fuel pressure is around 60 psi

 

[AKSNOWRIDER]

Yes fuel pressure is around 60 psi

its gotta be injectors then or wiring/ecu..that sucks..never heard of one doing that running it out of fuel before...they make a noid light for testing for current flow to the injectors(they plug in in place of the injector and pulse light when the injector is signaled to fire...) snap-on sells them(not made specific for a polaris but you can hook them up and they will work to show if ecu/wiring is all good to injector...

 

[chris05]

Thats a great idea didnt know they made such a thing I will see if I can locate a noid light. I am a noid with this sled right now......

 

[AKSNOWRIDER]

Thats a great idea didnt know they made such a thing I will see if I can locate a noid light. I am a noid with this sled right now......

try this...they are bosch injectors but any should be able to be made to work with a little ingenuity....
http://buy1.snapon.com/catalog/tools.asp?tool=all&Group_ID=1452&store=snapon-store

 

[welb]

You said in your first post that the sled dies when you move the throttle.That could be caused by the safety switches being out of adjustment.It may not be your problem but it is simple to check and one more thing to eliminate.

 

[chris05]

So I pulled off the tank and unhook the connection from the ecu going to the exhaust side injector. There are two wires there. I grounded out my multimeter on the tunnel. And I tested both wires for power they both run about 12 - 14 volts. So I guess that eliminates the ecu not sending the signal to the injectors. So that means the injectors are the problem? Hard to believe they both would fail at the same time. If one was bad wouldnt the sled kind of run. Really crappy though.

As for the safety switch in the throttle I dont think that has anything to do with it because that would cut power for the ignition/spark. And when I pour gas in the airbox I can get wfo on the throttle and it doesnt sputter or nothing until the gas in the airbox is gone gone.

 

[chris05]

Actually I just went and looked at the manual(see my attachment) Red/blue is 14 vdc through the ecu. Is this constant voltage. And the yellow is "switched to ground" So does that mean that the ecu is ground out that circuit when the injector is supposed to fire. So I need to be checking to see if the circuit is grounding out?

 

[05900]

Typicaly ECU controls injector ground based on inputs from sensors, check throttle position switches in throttle block for proper operation. Wiring harness for bad circuitry (open shorts)

 

[diamonddave]

you need to verify that the ECM is grounding the injector.

and just disconnect you wiring going to the bars

 

[diamonddave]

Actually I just went and looked at the manual(see my attachment) Red/blue is 14 vdc through the ecu. Is this constant voltage. And the yellow is "switched to ground" So does that mean that the ecu is ground out that circuit when the injector is supposed to fire. So I need to be checking to see if the circuit is grounding out?

I would check it both ways. some systems pulse the 12+ and some pulse the 12- ground

 

[AKSNOWRIDER]

the ecm should be pulsing the ground side..should be full 12 volts+ on the red/blue wires and the green and yellow wires are grounded thru the ecm to inject fuel.....

 

[chris05]

Got a nod light and put it on the injector harness. The one for a geo metro fits perfectly by the way. Lights pulses great. Rev up the sled while pouring gas in the airbox and the pulse increases in speed. So it looks like its not the ecu. Gonna try and pull the injectors tonight and get them bench tested. What a pain gonna have to pull the whole motor out to get to them......

 

[sno_mo_racer]

dont know if this will work for you..but worth a try...turn off the ignition key and hit the kill switch to the down position..now pull the sled over 5-8 times like your starting it..now turn on the key and raise the kill switch..should fire right up....if it does fire right up what happened is it used all the volts out of the capacitor..(from what I have seen putting battery voltage to the fuel supply jumper wont recharge the capacitor)..so far the only way I have found to recharge the capacitor is to turn off the ignition and pull the sled over..the stator will recharge it......

I ran out of gas last weekend and finally put gas today and wouldn't fire up after 10-15 pulls. I remembered reading this a couple days ago(thank god or else I wouldn't have figured it out maybe) so I turned key off and kill switch, pulled 5 times, turned them back on then she fired right up first pull.

Thanks AKSNOWRIDER.

Oh and for the fuel pressure test I do not have the gauge. Can you use a tire pressure gauge as it looks like a tire valve stem and I dropped the cover under the engine so got a tire cap and it fits. Also the manual doesn't say how to bring the fuel pressure back up after it has lost pressure or does it just build up after a couple pulls on the starter?

 

[AKSNOWRIDER]

I ran out of gas last weekend and finally put gas today and wouldn't fire up after 10-15 pulls. I remembered reading this a couple days ago(thank god or else I wouldn't have figured it out maybe) so I turned key off and kill switch, pulled 5 times, turned them back on then she fired right up first pull.

Thanks AKSNOWRIDER.

Oh and for the fuel pressure test I do not have the gauge. Can you use a tire pressure gauge as it looks like a tire valve stem and I dropped the cover under the engine so got a tire cap and it fits. Also the manual doesn't say how to bring the fuel pressure back up after it has lost pressure or does it just build up after a couple pulls on the starter?

the fuel system will bleed itself as soon as it builds pressure(regulator bypasses fuel to the tank to hold fuel pressure)..glad it worked for you....

 

[guidoxpress]

When I try and start the sled it runs for a bout 2 secs if you give it any kind of throttle it immediatly chokes out and dies.

any progress on this?

having the same issue with the wifes 06 RMK 700...starts up right away...revs crappy, then starts to bog and will die...

i haev literally tested everything...minus the ECU and injectors...