Need troubleshooting help from the vipec / electrical experts

Background info:

2012 pro 800 with a custom turbo kit.
Bought a Vipec ecu from the boys in Quebec and Sebastien has been trying to help me get this going but I haven't been able to reach him for a couple days.

The problem(s):

Currently, and most of the time lately, I can pull on the cord a hundred times and it won't start, it will stumble for a second then die every few pulls. No gauges light up and giving it gas makes it die.

but then sometimes the sled will start second pull, and idle low, around 1400 rpm, the gauge will flicker and the wideband will shut off and restart, looking at the datalog from the vipec it shows my rpm dropping to zero momentarily then coming back up, this would cause the ecu to cycle the power to my chassis power which explains the flickering. But why the RPM glitch?

and then, sometimes the sled will start on the 5th pull and run perfectly fine, idle is a little low at around 1500 but is steady, when it does this I can drive the sled with no issues, throttle response is good, everything is normal throughout the rpm range, no issues at all except that it took 5 pulls to start and it idles a bit low.

Using the vipec software I have confirmed that my kill switch works properly, and the ecu is getting trig1 and trig2 signals, but won't register any rpm when I pull it over. I have tried to start the sled with a battery connected to the sled, feeding the ecu power, the only difference this makes is that when I pull it over, the fuel pump primes, and it never fires up unlike when I pull it over without the battery how it tries to start for a split second.

Every mechanical component on the sled has been checked, every wire has been inspected and tested, I have replaced the following with no luck: stator assembly (cps air gaps set to 0.020"), voltage regulator, chassis power relay, fuel pump, capacitor, tps sensor (properly calibrated as per vipec). I know it's not a mechanical part because when it does start it runs beautifully. The only change to the sleds electrical system is the addition of a wideband on the accessory power, and the addition of larger fuel injectors, map and iat sensors. I have tried with the wideband unplugged and it makes no difference as well. Have tried unplugging my ignition switch and tether to rule them out as well with no luck.
Sebastien says he guarantees that it's not the ECU that's the problem, but I am out of electrical components to replace. I'm getting really frustrated and I'm hoping that there is someone who can help me out.

I've got datalog files for each problem for anyone who has the vipec software, I can email them to you to check.

Just installed a brand new stator assembly including new crank sensors, trig1 and 2 are setup correctly in the software, I assume they are what is used to sense rpm?
Coil resistances are good and wiring continuity checks out, this is the second stator I have tried, same results with both units.

I have tested all wires going to the ecu for shorts to ground and continuity to their respective destination. Everything checks out...

Thanks for the input!

Daltech said:

Why not try the oem ecu just to see if it fires up instantly when it wont fire with the vipec. Then you could rule out the vipec itself beeing the cause.

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I haven't tried that because I am running 1000cc injectors and since the oem mapping is for stock injectors It would be dumping 33% too much fuel.

gmustangt said:

Stock oem duty cycle idle is roughly 5% +\-.

You will be fueling 33% more of 5%.

5x1.33=6.65% DC. 1.65% higher duty cycle than oem.

Given all the variations of oem fuel pump out put, fuel filter flow, injector flow etc...I wouldn't be suprised if your sled could idle on a 1.65% increase.

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awesome input, thanks!
I will turn down my fuel pressure a bit and try the old ecu tomorrow, I'll come back with results.

Vi-PEC Powersports said:

Seen such a problem not too long ago. I found 2 problems: chipped piston on one side(87 psi compression) and the piston's chip damaged turbo vans(aero) . Symptoms was thebsled was super hard to start sometimes(10+ pulls) and sometime was starting first pull idling roughly or correctly , stumbling at low rpm until pulling like a rapped ape!! Chech compression, go to your pistons, also chipped reeds will make your sled act funny too. I would look else where but electrical now....when idling press "r" in your fuel table and all the runtime values will show up and you can check every single switches , inputs etc.. make sure chasssis ground is correct too.

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Pistons, cylinder and reeds were all new when the new vipec ecu and turbo kit was installed.
Thanks for the tip about the runtime values, I was trying to remember how to do that.

So, this morning I did back to back tests, tried starting with the vipec installed, 10 pulls and no go, removed the vipec and installed the oem polaris ecu and first pull 1850rpm idle, no problems whatsoever.

I suppose this narrows down the problem to the mapping, or the ecu itself.
now I wait for Vipec powersports to return my calls.

Thanks for all the help guys, I'll let everyone know the outcome

Spoke to Sebastien at Vipec, sent my ecu back to Quebec, he is going to test it and we'll go from there.

Vipec Powersports has had my ecu for 2 days now and hasn't returned my calls, hopefully I'll hear from them soon.

Just got off the phone with Sebastien, looks like my ecu was the problem. He's sending a replacement right away.