Oseberg

1998 LS400 (1UZ-FE VVT-i) EGR Location

I've looked all over my engine and all over the Internet. Everything indicates that my 1UZ-FE VVT-i has an EGR, but I can't find it anywhere. I just barely failed smog with too much NOX, and want to make sure the EGR is not clogged.

Please help me find my EGR.

Yamae

A 1UZ-FE for a 98-00 does not have any external EGR pipe or a passage. It is controlled by the valve timing. So the EGR is done internally in the combustion chamber.

Oseberg

That explains why I can't find it, but what's this?
http://www.carparts.com/details/Lexu.../SIEGV862.html

Oseberg

Yamae, you're probably right, but here's another one.
https://www.napaonline.com/napa/en/p...521_0232731984

Yamae

Why don't you use it if you trust that?
I don't guarantee that though.
You'd better see the service manual before you act.

Oseberg

I believe that you are right and carparts.com and napaonline.com are wrong.

I was just hoping that you were wrong, because I know how to clean a clogged EGR and I know that a clogged EGR will cause high NOX. But with no EGR to clean, I have no idea how to solve my problem. I guess I need to check my smog results for CO, as that should tell me if I'm running lean. But with a functioning O2 sensor, I shouldn't be running lean, right? How does one adjust the air fuel ratio in a fuel injected engine who's air fuel ratio is controlled by the computer?

saleenssc

I have a 98 with 174k miles on it. Im curious how many are on yours? Now you got me nervous. Im in Virginia which has tough emissions requierments.

Oseberg

I've got about 230k. I have had no problems with this engine ever, so I've had to learn nothing about it until now. I'm quite impressed with what I've been learning. I'm quite familiar with older carbureted engines. I really like the VVT-i technology, but unfortunately this means that clean engine oil is a lot more important on this engine, as sludge and deposits can cause serious issues with valve timing. I'm pretty sure the oil pressure is used for other critical functions as well, so who knows what might be going on. So now I'm looking into ways to remove oil sludge from these engines. I'm also looking into any and all other components that might cause the engine to run lean. Maybe clogged fuel injectors? So I'm researching fuel injector cleaners as well. And what about the mass air flow sensor? Can it cause the A/F mixture to be off? It seems like none of these things should be that critical since the computer should be looking at the O2 sensors and automatically adjust the lookup tables to compensate for any bias in these components.

But, what if 1 or 2 fuel injectors are 50% clogged? Does the computer have a separate lookup table for each injector? Is this even useful or possible with 1 or 2 O2 sensors that are positioned after the exhaust from all the cylinders is combined? What if the O2 sensor is trying to adjust the average fuel to all the cylinders combined, but 6 are getting a little too much fuel while those 2 that are partially clogged are getting way to little fuel and therefor running lean and hot so they are generating a bunch of NOX?

So, right now I'm suspecting that I might have one or more partially clogged fuel injectors.So, the first thing I'm going to try is fuel injector cleaner.

I'm watching this guys videos to see what works best for cleaning carbon deposits.
https://m.youtube.com/user/paintballoo7

anniverse

I have a Lexus GS300 1999 and it has a ECT sensor that is supposed to go directly
to the ECU and ECU controls the air/fuel mixture