3RZ EGR valve gasket

I removed my EGR valve to clean it and the port into the throttle body because of a recurring P0401 code on the CEL.

The gasket on the throttle body side came off after a while off prying and prodding, but the gasket on the egr tube side seems welded on.

I'm soaking that portion in rust penetrant to see if that helps seperate the two.

Anyone else encounter this issue??

 

Wire brush and a razor blade got it for me.

 

I used a wire brush on my drill around all sides, before i tried prying with a razor blade. Even tried a sharp chizel with a hammer and it would not budge.

 

Hm. Maybe a utility knife under a corner? You're on the right track, but it might just take some persistence to get it.

 

For my dumb eye it looks like its just surface rust, and the gasket is gone.

I would use a higher speed wire brush and clean it as best possible.

Exhaust gaskets like that are pretty forgiving as long as they are new.

 

I agree. A razor blade scraper.

 

Here's a cleanish one for reference.

 

Just delete the EGR system

 

Why?

 

Keep from blowing hot exhaust and carbon back into your intake manifold
Simplify the clutter in that area of the engine bay
One less thing to maintenance as the OP is doing

I've done that on 2 different 3rz motors and will do it again if I ever own another one.

 

So I removedt that center button and it made me think the gasket was thicker. It's not, I just need to clean and put the button back.

 

Sharpened up an old wide flat bladed screwdriver on a grinder and used that. Finished off with a wire wheel and it was all good.

 

P0401 is the insufficient EGR flow, right? I had that DTC going on when I first picked up my taco with 3RZ.
Make sure vac lines associate with the EGR system are all clear, don't overlook this step!
The modulator can be tested with a hand held vac pump, like a Mightyvac or similar. The VSV under the intake can also be tested by applying 12VDC and making sure each of the 2 outgoing ports hold vacuum(or just replace VSV with Aisin brand one(they make it for Toyota) and new vac lines and new modulator. Also clean the EGR temp sensor as that temp sensor is how the ECU reads how much EGR is coming back into the intake.
The EGR valve themselves rarely fail and I've only seen one failed before on any Toyota and even that's because the previous owner attempted to 'fix' the diaphragm

 

Also, as far as the vac lines go, also check their ports on the throttle body. Mine were all plugged up, although that was giving me an 0402.

You can also check the temp sensor with a multimeter. I think anything above 2.5kohms is OK.

 

I will check the sensor tonight and report back.

I cleaned the TB thoroughly and had to a few clogged ports that I took care of.

 

Yeah, good point, excessive EGR flow (P0402)can happen as well from carboned up ports or lines.
I learned a lot more about these heaven forsaken EGR systems than I ever wanted to, from the 80 series Land Cruisers. Obviously glad I learned it now in hindsight but boy can it be frustrating
Once the whole theory/premise of operation kinda clicks in my noggin, it made it MUCH easier to troubleshoot and diagnose issues with it.

 

A test not given in the repair manual is to apply vacuum with a hand vacuum pump to the big bottom port on the modulator and check that it holds vacuum. The rubber diaphragm inside gets old and brittle over time and will develop a crack. If that diaphragm is leaking the modulator won't be opening the EGR valve correctly.

Those modulators are very specific to each engine, so if it's broken you may have to go to Toyota to get a new one, but it should last a long time, probably the rest of the life of your truck.

 

The EGR Valve should have a metal gasket that comes off very easy unless someone used high temp
exhaust gasket maker

 

Have you deleted the EGR from the 3.4?

I just installed a temperature gauge in the supercharger on the hot side going into the engine
and my intake temperature is a WHOPPING 140-150 degrees with zero boost.

I didn’t even think my intake temperature would be this high until I installed my supercharger temperature gauge.

I might have to delete my EGR system and get back to normal intake temperature of 100

 

My valve is still working correctly 22 years later and 625k miles,
They don’t fail very often
I’m 99 percent the 3.4 valve is no longer available from Toyota, FYI