Injectors not firing correctly

Engine, intake, exhaust, EFI, chain, sprockets, etc.
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Sled_fiend
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Joined: Wed Mar 10, 2021 10:41 pm

#1 Post by Sled_fiend »

I'll start from the top. 2002 X440S. Rode the bike last at Loretta Lynn's on October 2016. It sat for a few months over the winter. Went to start it around February and found the gas had gone bad and the battery died. I charged the battery and changed the gas. I assumed the fuel injectors were clogged because it would fire once but not run.(after fresh gas). If I kept trying it it would eventually fire and run at a really fast idle then die like a carburetor running out of gas. I bought new injectors and installed canniboomers throttle tamer bell crank at the same time (planned upgrade unrelated). Same problem. I had purchased 4 injectors so I swapped to the other two. Same problem. Contacted canniboomer and he suggested energizing the system to prime the fuel system and then rotating the crank by hand to see if the crank position sensor is ok. It is, the injectors fire and the pump cycles with each rotation by hand but will not when cranking with the starter. I thought maybe the battery was weak after being dead and recharged so I bought a new yuasa. Stop the same problem. Looking at the injector spray, the injectors fire when you first hit the starter button but do not fire again as it cranks. Any ideas? This bike had been reliable up till now and I want to ride!

polyesterpig
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Joined: Wed Mar 10, 2021 10:41 pm

#2 Post by polyesterpig »

Fuel quick disconnects are messed up and not flowing properly. I gutted mine and no more problems. Also put a new fuel filter on. Even if yours seems to flow fine. I purchased larger fuel filters from Napa auto parts. My fuel pump doesn???t work so hard now!

wistech
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Joined: Wed Mar 10, 2021 10:41 pm

#3 Post by wistech »

Injectors fire a large visible burst of fuel at first crank and then they are very hard to see because of reduced spray for normal idle . This is how a cold start is 3 short taps to get much more starting fuel before a actual crank of the engine. Are you sure the fuel pump is not running while your cranking? Do you have a meter on the leads to measure voltage ? Dont short the fuel pump wires to ground or you will fry the fuel pump driver in the ecu.

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