I just bought a 2006 king quad 700 and I am having trouble getting it to idle consistently. It will idle good but then the FI light will turn on and the idle will drop and it stalls if I don’t give it throttle. Sometimes when I’m riding it will not happen at all. The light will come on without the quad running. It will go away by itself without me doing anything to it after sitting for a couple hours. Any ideas? I also have an aftermarket ecu so I can't see the codes

 

Easy things first, check it is charging properly. Next, can't remember if it was 450 or 700 but on one of them, the wires to the temp sender in the cylinder were too short and broke with the constant engine movement, so check they are OK, bad to tell, as they break at the plug on top of the sensor. Only other thing I can suggest is getting someone who has an OE ECU to swap his ECU onto your machine, and read the fault code that comes up. Should be plenty about, as many owners swapped the original ECU for the later one which doesn't drain the battery.

 

It was getting around 13.8 volts while running which seems a little low but not much. I added the ground like I have read online but it didn’t seem to make a difference. I will check those wires for the temp sensor soon. I am going to replace the fuel pump solenoid as well but if none of that works I will probably just buy a used ecu to check the code. Thank you

 

13.8v was about what you got without the modifications so it should run OK on that. We used to fit another positive, direct from battery to regulator, as well as a negative. This fetches the charge up to about 14.2V. We always put a fuse in this line. Can't see fitting a new fuel pump solenoid doing any good, it must be working for the engine to run. However, you can't be certain of anything with electrical faults.