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Discussion Starter #1
If anybody can help me with this intermittent EFI / Electrical problem it would be greatly appreciated. My 93 Indy 500 EFI won't cycle the fuel pump @ times. At cold the sled will usually always cycle it's 6 second prime , although after a motor rebuild I usually have to unplug the ECU @ least once after the sled stalls . The sled will stay running after the second attempt. Just recently I warmed the sled up & shut it down,but when I tried to restart it wouldn't cycle. I unplugged kill switch,Throttle sensors & Ignition , witch I found out later from reading some of the forums they shouldn't affect the pumps ability to cycle. I wiggled all of the connection blocks which have since been cleaned and greased with dielectric grease, checked all grounds , replaced battery , removed 12v circuit breaker & ACS switch to clean and make sure grounds were good.Now after sled sits for awhile the pump will cycle again and the snowmobile will start. While riding the sled has lost electrical power and died, same symptoms . Very frustrated,please help.
 

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Sounds like the self shutoff time delay relay. FYI-The fuel pump will not run if the fuel system is up to pressure. It has been said you can use these as a replacement Airtex 1R1227 Power Window Relay - TURN SIGNAL RELAY but I have not tried them yet. Just need a way to mount them. You can find them at an auto parts store or ebay. Good luck and post back if this fixes your issue.
JJ
 

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Discussion Starter #4
Relays came in this morning, they clipped right in. Started sled up and warmed it up good,seems to be fine. Going for a ride later and I will post back. As far as mounting them I tie wrapped them around the original holders. Still had to unplug ECU once to start machine. Wondering if motor is still tight from rebuild or something else?
 

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Post back with results. Good Luck
JJ
 

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Discussion Starter #6
Snowmobile ran great all day,thanks so much for your help. Do you have any ideas why it isn't starting like it used to.
 

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So do you have to unplug the CPU every time or just that once? Are the different symptoms or the same?

JJ
 

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Discussion Starter #8
No not every time, just at cold start or if it has been sitting for a long time. It used to start with one small pull to cycle pump then one long. It would start every time.
 

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Should take one to cycle the pump and fire on the second maybe third. What are you seeing? JJ
 

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Discussion Starter #10
Hi JJ , Cycles on first & fires on second but won't stay running. I've tried pulling IT again a couple of times with short cycles and it won't fire until I pull plug on ECU. The next pull it fires and stays running. Once warm, first pull every time. It Seems like it's not getting enough fuel for a cold start. Idle when warm 1600 , cold just under 3000.
 

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Coutter,

You rebuilt your motor, Correct? New piston/rings and maybe new crank seals? So your compression is greater than what it was before. Motor ran great before the rebuild and after you are having these issues but been able to work around them.This is fuel related is it too much or not enough with the first pop. Did you add some two stroke in the fuel tank?

So we have a few things to try next. It could be as simple as adjusting the TPS. I would start with checking the resistance of the TPS while still installed, closed and open. You will need a multimeter that can read those values.

I have attached three sheets for you to use. It explains cold starting, TPS and MR adjustment. SO after it pops and dies you will need to keep pulling and holding the throttle open in increments to determine what you need to do next. Try it until you get it to start without unplugging the CPU.

If you need to give it very little throttle it needs more fuel to run. If you have to open the throttle over 60 Degrees then it would need less because it is flooded.

Post back what you found.

Goodluck
JJ
 

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Discussion Starter #13
It seems that with another long cycle of fuel it will start and stay running. No popping, just quits. Would like to check TPS sensor using 5v power supply seen on another tread but can't seem send Radio Shack parts to Canada. Thanks for replying.
 

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Discussion Starter #14
Tried checking TPS sensor using ohms meter ,got same reading open & closed, not sure why. First tank of fuel after rebuild I did have 2 stroke motor oil in it ,also wanted to make sure oil pump was working properly. Then changed plugs.
 

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Discussion Starter #15
Didn't receive the 3 pages ,but if they are from the Polaris shop manual I think I've read them. I'll check them out.
 

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I remembered when I woke up this morning I did not attach the sheets. So here they are so everyone can have them.
The cycling of the fuel only pressurizes the fuel rail. Have you check the fuel pressure and the flow? An additional cycle to add more fuel to the fuel rail tells me that it is not getting enough fuel. You may have checked this already but sometimes it is good to recheck.

FYI-Rebuilt a Direct Injected motor with new flywheel and stator. Tested good on the bench, spark, fuel. I installed it and had nothing. No spark nor fuel. After chasing problems with the stator, injectors, coils, realized that I did not reconnect the CPS, (SLAP TO FOREHEAD) I connected it and ran great.

Let us know the progress.

JJ
 

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