Any tricks a shop would need to know to successfully replace a timing belt?
Brought my RX300 in along with an ebay water pump/timing belt kit (possible culprit) as my water pump was dumping coolant overnight. Replacing the water pump has helped preserve my coolant, but now I've got a timing belt issue, something goin on with VVT-I bank #1. Other posts say it's off by a tooth, but the mechanic's shop has tripled checked and also bought a new Gates belt. The Gates belt markings were different than the Lexus OEM timing belt off ebay. When they had my ebay belt on, the car ran fine although at lower RPMs. Had a CEL.
Now that the Gates belt has been installed, it's still running mostly fine with a CEL. When the car is cold, there's a small-ish sound that occurs while the vehicle is cold and you are in drive/accelerating.

Is there some sort of trick these guys have missed putting the belt on? Is it worth getting them to order a kit they trust and just paying them another $600 to put it all back?

Thanks.

 

I don't think you need to remove the timing belt at this stage. Just remove the valve cover and recheck the alignment marks match [note at this stage ignore the marks on the belt]. Confirm that the main pulley and the two cam marks line up. Once that is confirmed ask the tech to verify the vvti sensor wires are intact and the mounting is not crooked/bent.

Salim

 

If the timing marks look good after checking as posted above, the next step is for the shop to do a Cam vs Crank sensor waveform using an oscilloscope tapping into the wires at the ECM.
This will tell exactly what's going on.

This is one I did for the 3MZFE and when I look up the 1MZFE in the RX300 manual the expected waveforms should be the same or similar but you get the idea.
Waveform never lies and tells you exactly where the cams are hitting in relationship to the crankshaft sensor and both banks should match with reasonable accuracy within a few degrees.

Notice my cams are not perfect as seen below- they are off 5 crankshaft degrees(pink line) after a new oem belt installation. This is not enough to throw a code. My theory is the ecm will adjust for minor belt differences but being off 1 tooth on the cam gear is a 15 crankshaft degrees error and will probably throw a code and be very visible on a waveform.

Timing belt is most typical but there may be other things that can throw off the waveform- if code never existed before the service work was done, it's probably a failed T-belt install or damaged crankshaft gear/sensor IMHO.

Yellow= crankshaft sensor, blue= cam sensor bank 1, pink= cam sensor bank 2