salimshah

Did you buy OEM knock sensors from a reputable place?

Recheck the connector and make sure you hear them snap close.

Salim

av8rga

Check engine light is back on. It has been coming on intermittently last year or so, but now it's on solid. Had the codes read yesterday - P0330. What the heck?! I changed both of these and the harness 3.5 years/40k miles ago. When I changed them the first time, both tested Ok, which always raised my curiosity of whether they were actually the problem.

Four situations IMO:

1. The engine is really knocking. Sensors are doing their job and something else is wrong like timing or?... I never hear anything in fact I'm always impressed how smooth she runs with 150k

2. Wiring from sensor harness to main ECM isn't right. Bad ground, bad signal etc.. Guess I could jump all of it If I knew the pin sequence.

3. Bad ECM. Anyone have a loaner?

4. Bad knock sensors. Highly doubt it since they are relatively new and the ones I removed tested Ok.

Gotta get the fixed once and for all. Emission won't pass and as we know, this code shuts down the transmission overdrive

Thanks for any help. Tim

carguy07

Just a thought: https://www.clublexus.com/forums/rx-...ck-repair.html

kantgitit7

Thanks a million Salimshah,took my time broke it down in about 1.5 hours, going to change rear valve cover gaskets and plugs why it is easier to access from this tear down.

Quang12345

Just want to add. Whenever remove the hidden aic hook bolt, get a longer bolt and put it back with a spacer. So that you can use a wrench to install it or remove it next time. I also added a longer ground and mount it with easier access place.. Thanks

av8rga

This works. Beats knuckle busting, back breaking, down to the gut of the engine knock sensors and harness swap. After all that, my engine MEL'd the same codes 3 years later. Factory parts... If you do decide to do all this work, swap everything you can at that level being plugs, hoses, and left/right valve cover gaskets. If your covers aren't leaking yet, they are either new or about to leak. Then do the above hack.

Tim

gazi001

How do you clean the injectors?

matts6887

I would agree here. Doesnt make sense not to do all the extra stuff like plugs, valve covers, etc while the top part of the engine is torn apart.

gazi001

I replaced the Knock Sensors, By pass hose, Harness, Manifold gaskets and clean all fuel injectors few days ago. I made this video for our members.

salimshah

Gazi:

Please add your diy to an existing thread (if it exists). If not please add a link to the DIY sticky to your new thread.


To release the pins of the cowl, take a small socket and shove it over the pin. The socket size should match the pin and as you push it on, the spread on the pin is squeezed and the pins come out super easy. [I use 1/4 SAE socket]

Salim

Pzindy

I am into this, and having a very hard time re-using the old spring clamps. Pliers keep slipping off, and I am getting frustrated.

The new hoses did not come with clamps. Do you suggest buying clamps from the dealer, or are there acceptable aftermarket alternatives? My internet searches seem to indicate that worm drive clamps are not a good idea.They sure would be easier to install though.

salimshah

Regular pliers do not work well as they form a "v" which tends to slide off as you squeeze. Slip joint pliers work lot better as they keep the squeezing force perpendicular to the clamps.

Slip joint pliers look like:
http://www.homedepot.com/p/DEWALT-10...4427/206173773

Is you bye pass leaking or bulging. Since the hose is flexible, you can push it out of the way.

Salim

Pzindy

My old bypass hose did not appear to be leaking, but it certainly was no longer "flexible". I had purchased a new one before I started, and ended up destroying the old one anyway to get it off; so no longer have a choice about replacing.

I will try slip joint pliers. Thank you for the pointer.

jim662

I did this repair over the weekend and have the following 2 cents to add.

In order to remove the throttle body to bracket bolt, remove the heater hose closest to the passenger side. That gave me plenty of access to get a gear wrench on the bolt. I think it was 10mm. I tried for a long time and there was no way I could get it without removing the hose.

The 14mm bolt on the plenum to bracket is a beatch. I wound up using a 1/4" socket and ratchet. It took a good long while to get it though. Also, I had to push one of the hard lines mounted to the firewall over 1/4" in order to have room for the head of the ratchet in that little space. Getting purchase on the bolt was being blocked by this line as it was stopping the ratchet and socket from fully engaging the bolt head.

If you're doing this job, buy the wire harness even if you think you are good removing wire connectors. Both of mine just snapped when I put any pressure on them.

The upper radiator hose manifold needs to come off. I didn't realize it at first. This means removing the two long bolts that go through the engine dog bone stay.

I did not have to disconnect the fuel line. Once I freed the lower intake manifold, I just lifted it out of the way with the fuel line connected.

And parts.... I used Toyota/Denso sensors bought through ebay. The name "Denso" was stamped in the plastic near the connector and they came in Toyota packaging. They were about $60 each. There was another seller selling "Denso/Toyota" sensors that were not stamped "Denso," though they were in Toyota packaging as well. I was so sure they were Chinese knock offs that I spent the extra money. Now, I don't know if they were legit or not, but neither of the two sensors I took off had "Denso" stamped on them. And, around the bolt head of the sensor, they were etched with the same "M" in a box that is seen on the $10 Chinese sensors. So, I have no idea what is a true OEM sensor and what is not. According to Denso though, if they make them, their name is on it. So I don't know if Toyota had a different OEM supplier in 2001 or if the sensors had been changed in the first 100K miles of life.

The whole job took me more than 8 hours leisurely. That included a good long time looking for dropped bolts.

Pzindy

Thanks to all the previous posters above I got this done. I have done oil changes and changed one air/fuel sensor, but not much else DIY on the RX300 until now. This project was daunting, but if someone with my little experience can get it done, then anyone can.

I carefullyy labeled everything with orange dust tape and a sharpie. It was 2 weeks from the time I bought the parts until I had everything back together. I do have the luxury of an extra vehicle, which made this less stressful.

I think the biggest challenge was the hidden bolt on the throttle body. I got it off easily enough, but could not get it back on. I seem to have lost it.

The first time I put it all together I had some coolant leaks. Re-did some clamps, to throttle body, and upper radiator hose.

For the bypass hose, I gave up on the spring clamps, did not want to use plain worm drive clamps after researching them. Finally decided on two constant-torque clamps from NAPA. I Also tightened the front engine block drain.

Drove it about 30 minutes tonight. It shifts into O/D, no CEL, no overheating, and no apparent leaks!

It took me a lot longer than going to a shop, but I got it fixed and learned a lot about the RX300's systems on this project. Not really sure how much labor charges I saved. I bought sensors, wire harness, PCV valve, and radiator hose from Lexus dealer. Gaskets from Autozone.

Again, thanks to all the people who posted great help in this thread!