Hello everyone. Need some insight on my newly acquired Is300. I have no previous records of the car, work done or anything at all other than carfax with 5 failed emission inspection attempts.

Anyways, car is not running right. sputter under 4k rpm. after 4, boost hits but still seems like a fuel cut. on idle car shakes, not constantly but it does, when it does the AFR gauge goes to leaner side. idling cold 10-11, idling warm 13-14, missing sputtering 16+. I pullled the sparks, they are black as if the car is running rich? i did a compression test on cold motor, got 120 across all 6 with maybe 5-10 psi difference between cylinders. adding a bit of oil inside the cylinder did not make any difference in the readings.

now for the things i dont understand. there is no maf sensor anywhere in the piping. there is something hanging out in the bay which looks like a maf but im not sure. Cam position sensor! the cps is just hanging out also and there is a plate on the head where it should go into. this is vvti motor and i was told vvti motors have only one sensor around cylinders 5-6 closer to the firewall. i tried to search why would someone delete cps (since they sell the plate cover for 80$) but couldnt find anything.

My guess it may need a tune. Also, it is a vvti motor but both cam gears are hks so the vvti sprocket or gear was basically removed, the solenoid is still there. i think the timing might be incorrect. adding oil to the cylinder did not change the compression test reading so im guessing the valves arent closing all the way.

any thoughts input is greatly appreciated. I am the point of first two parts of the intake removed. im wondering if i should remove the cover and put the cam sensor back in the head.

 

Wow what a rats nest! before you start with anything, go to a junk yard and get a ge vvti head, a working maf sensor, oem injectors, and an 01 engine harness. The previous owner is dumb for getting rid of vvti and sorting out that wiring disaster is a lost cause. You may as well put a HG in while the head is out. Get the car running with stock fuel before you touch those other electronics to ensure the PO hasnt destroyed anything else and to get is registered. Then after that is all said and done, hook up the other electronics and get it tuned by a professional

 

+1 for rat *** nest. For sure start all over

 

I agree with this. This car's motor is blown. It's gonna need a new one.

Might as well buy a complete GE VVTI motor and harness from a wrecked IS300 and get the car running in stock form. Pass emissions. Then go from there

 

Before you do anything, get a cheap inspection camera and stick it into the spark plug hole to get a picture of the pistons. It could very well have been changed over the GTE pistons which will lower the compression ratio. If the engine isn't smoking out the tailpipe then it likely just needs a tune or some sensors replaced. I wouldn't immediately jump to the conclusion that the motor is toast.

 

Also, it is likely the car is running a standalone ECU so it doesn't need the MAF sensor and perhaps the standalone can't control the VVTI so maybe that's why the VVTI cam gear was changed over. It could very well just need to be cleaned up and tuned....