VU high idle motor gets hot fast

[Fleash]

hey guys had this problem ever since i put a vx motor into my VU ute, i hit flood water at the start of the year and blew a hole in my block so did a engine swap, the vx motor idles at a steady 2k, just tap the throttle and shoots up to around 3-3500 hangs for about 2 secs then slowly returns to 2k. i have done multimeter readings on all the sensors and they seem to be fine aswell as the maf/tps/iac valve. it will run for around 2-3 mins before the engine light is displayed but my code scanner isnt picking it up. when i start the car again after it displaying the engine light it dosnt come on untill it runs for a few mins. checked for vacuum leaks with a can of carbie cleaner but to no avail. also it gets quite hot really quick, would anyone have any clue as to what is goin on or what i could try to fix it? both motors are ls1 gen 3's cheers in advance

 

[Immortality]

Did you swap any parts from your original engine onto the new engine?

 

[Fleash]

sorry for late reply, phone wouldnt let me post. used all the bolt ons minus the water pump, ive cleaned the maf,iac valve, throttle body and air intake multiple times. i have the fuel rail and injectors for the current motor but didnt install it as my old rail with injectors was still attached to the fuel line. didnt think i would have such an issue as there both gen 3's. i had to use my old oil pickup line as the new engine was buggered. used all new gaskets as you normally would.

 

[Fleash]

just installed new o2 sensors and made no difference also changed the coolant temp sensor as its also a known cause but no luck there. unpluged the iac valve while it was running and also on a start with a slight drop in rpm, about 2-300 rpm drop but revs would still hang if throttle was tapped. unplugged maf while running with no change in rpm also so im gob smacked with this.

 

[SID888]

Is the PCM from your original engine or the VX engine?

 

[Fleash]

from the original engine.

 

[SID888]

Ah ok thought it may of been from VX engine and had been mafless tuned which would explain no difference when maf was unplugged.