1KZ-TE knock/tick sound and occasional misfire.

[McHans]

I have been struggling with my 90 series having a bit annoying knocking sound. Its louder when cold, allmost gone when warm but still hearable to driver seat when driving. Its worst between idle and 2k. Oil doesnt have any glitter in it.

Then there is this misfire problem, its noticeable when i drive ~80km/h and the TC is locked, when i get it under load there is slight stuttering.
Also it appears when i keep rpms around 2k, its doing it randomly
Injectors were fine, installed new denso tips and opening pressures were bang on.

 

[KiwiBogan]

Knocking sound I usually relate to the timing control valve. It usually is followed with a Check Engine light and error code P1220, but not always.

Next time it's knocking, stop, turn the steering hard left or could be hard right actually? Jump out the car and coming in from under the front left wheel arch, find the wiring harness that plugs into the bottom, rear of the injector pump. Give it a wiggle. Try pushing the plug into the socket a bit harder. See of that makes a difference.

I've had a whole heap of issues in this area and it all started with a damaged wire at the back of the plug due to engine vibration and just old age/brittle wiring. Also the pins in the socket sometimes make poor contact inside the plug. It would be easy to make the mistake of assuming its the whole TCV that's faulty and replacing it would resolve the issue (at great cost). But if you reach in and carefully bend the (quite strong) blade style pins with your index finger, that can fix the poor connection again.

This is all assuming the TCV is the cause. Another possibility is that the oil pump is getting tired and taking a bit longer to pump the oil up to the top of the engine after sitting. Or oil level too low?

 

[McHans]

I have swapped the whole injection pump about 2 years ago when i had problems with warm startup, so i doubt that the knock is IP related.
When cold it sounds like a rod knock but as soon it warms up its almost gone.
Could the stuttering/misfire be from spill valve?

 

[KiwiBogan]

I have swapped the whole injection pump about 2 years ago when i had problems with warm startup, so i doubt that the knock is IP related.
When cold it sounds like a rod knock but as soon it warms up its almost gone.
Could the stuttering/misfire be from spill valve?

Nup, not the spill valve. It makes a faint click sound when the solenoid is activated and not really loud enough to be heard over the running motor. Besides, it would click so many times per second it would sound more like a brrrr than a click click click sound.

What I'm saying above is not the TCV valve on the pump itself that could be faulty but the wiring going to it or the plug on the end of the wiring.