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so i'm in an epiphany. my Lexus sometimes will start and sometimes wont start. had it running 2 days ago but in order to start it i have to disconnect the EFI Main relay under the hood  wait a couple seconds then jump the b+ and the Fp things under the diagnostics port inside the engine bay.   engine cranks really fast (not used to cars cranking that fast maybe) just doesn't get any fuel. when you have the key on the on position and you jump the wires you can hear fuel going into the engine. what do you guys think that could be? Fuel Ecu, cold start injector?  any help would be much appreciated. thanks! 

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Bit disconcerting to hear you say the engine is cranking fast.

First thoughts are that is has lost some cylinder compression, causing it to turn over quickly.

I would check the compressions and ensure that the camshaft drivebelt/chain is correctly positioned.

Crankshaft / Camshaft Position Sensor is a possibility as well.

Keep us updated on what you find

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i replaced the alternator because the battery was pushing well over 14 volts (leaking out the battery vents etc) anyways it still has a hard time starting, in order for me to start it i have to turn the key to the on position and disconnect the EFI main relay wait 1 second then plug it back in then you can hear the fuel pump being primed, after you do that you're good to go. after driving it for a while last night i noticed that the EFI main relay was really really hot. i know that heat can do funny things to electronics, but my question is do they normally get hot? and ive noticed that these cars get hot as well even driving on the interstate (coolant temp is fine). ive been looking at doing the BFI  mod so that the engine can breathe a bit better and maybe cool it down a bit. One more thing, does anybody know how to do the 12v ecu bypass mod? i know that its on Clublexus but i cant see the pictures for some odd reason. Ill keep you guys updated if i fix anything!

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