Originally Posted by Bocatrip

It's not that encouraging to hear about the ticking noise. I'll need to take notice of it the next time I go for a another test drive to see if it's anything significant.

Originally Posted by MJA1951

I noticed it also and the service department said the same thing about the injectors. It maybe normal but it's still disappointing to hear from a Lexus!

Originally Posted by neurocity

To go into more detail. There are 12 injectors. 6 Port and 6 Direct. (Different sizes and flows)
The 2GR-FSE plant which is in (2nd gen IS350's and 350c's, 3rd gen GS350's, 450h's, 4th gen GS350, *4th gen GS450h and RX450h's use the same plant except the Atkinson cycle and Cooled EGR)

Works like this. (99% sure this is correct)

At low RPM (speed) the port injectors and Direct Injectors work simultaneously, hence why it sounds like mini muffled claymore mines going off under the hood. At high RPM (speed) the computer switches over to 100% direct injection (pretty sure synchronous with the VVTi compensating A/F ratio).

Noisy as it is... its still rated as one of the best engines made by Wards.

Originally Posted by noncom23

Great post. I beliveve this is also part of the system that controls
carbon build up issues.

Originally Posted by mrsardar

Frankly speaking why does it matter if there is ticking noise coming from our engine it is suppose to have it by design, heck even my dad LS 600hl engine has noise.

Yes if it is making noise like a diesel engine then you should be worried. other then that enjoy your GS it is an amazing car.

Originally Posted by neurocity

Never even made that connection... It does make sense. All the injectors the changing ratios.

Originally Posted by neurocity

I would be curious if the LS600's 16 injector D4-S is louder than the V6 version of the D4-S. Id bet it was quieter because of the larger cover and the way the plenum covers the direct injectors.

Originally Posted by mrsardar

Probably you are right but it is no where as quiet as 1st gen LS V8 engines. the other day i went to the lexus dealer for service and customer had the 1st gen LS and it came up right next to me and it was just amazing how quiet those engines are.