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Discussion Starter · #1 ·
Finally got some snow here only 10 inches but got the sled out and ran great. Got it out today temp is about 15 degrees colder and from 3/4 up it bogs out almost sounds like it's gurgling but plugs still look good. So I tried jumping up 2 jet sizes and it was the same if not maybe a touch worse. I dropped down to 280's and it was a touch better but still very bad up top. 3 days ago I noticed my air intake tube was not hooked up to the air box so I hooked it up. Well after the 280's didn't help I said "Edit for bad language" it it's worth a try and unhooked the intake tube and pushed it aside it tried it. Wow that thing flat out rips. So is there any way to bypass the sensor in the intake? Or do I just need to hard jet because the power jet is flooding it up top?

Sled is a 770 d max by the way
 

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Because it is a air temp sensor its a resistance type sensor. Find the resistance that the ecm needs to know to optimum temp and wire the correct resisters in. Or hard jet. With the tube set aside its just reading ambiant temp under the hood. Or just pull the sensor out of the tube leave it plugged in and cap the intake tube and see what happens. But the power jets will still be active. Could be a faulty sensor as well. Most automotive type sensors use a 5v signal with a parameter range of 0.5 to 4.5. So 30° could be 1.2 etc, if the sensor falls out of that range (.5 to 4.5) it will throw a code. As long as its in that range it may be reading incorrectly but still sasisifies the ecm. With most sensors the 5v reference voltage is shared by all the engine sensors. Coolant temp,air temp, oil pressure and so on. If a sensor internally shorts it will wipe out that 5V signal to all the sensors.
Just a few ideas for ya lol. I'm board can ya tell!
 

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Discussion Starter · #3 ·
I'll try just unplugging it but I read somewhere that when the power jets fails it will fail opened up all the way so I was under the asumption that if I unhooked it it would leave the power jet wide upon but now that I know what it is I'll try it and give it a shot tomorrow.
 

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You're correct. If the pj fails it will fail open so it doesn't go lean. Un plugging the sensor will throw a code though. There was a post on here recently on what a good pj should ohm oit at. Can't remember what it should read when good. Sorry.
 

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Discussion Starter · #5 ·
If I was to hard jet do you know what a stock pilot jet and a 280 main jet would be with out the power jet?
 

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Most RS's when hard jetted went to 350 main and stock pilot.

My guess is youre still 1-2 sizes rich on the main, which is why shes gurgling. I'm at 250 main with my rk tek 780 and most dmax 770's are at 260/270.

Power jets were NOT a problem after year 2008, despite what you read. I'ts used as an excuse when one doesn't know how to properly tune/jet a sled.
 

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Discussion Starter · #7 ·
Well with 280's and the boot pulled aside the plugs are darn near perfect
 
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