Cleaning the EGR valve....

takza · Post by **takza** » Mon May 31, 2004 6:37 am

Note: Aftermarket EGRs seem to cost from $163 to $266 (don't ask what Toyota wants for one)...used ones should be found cheaper...but might still need cleaning. Main issue might be whether the diaphram works.

Here are some photos (taken by a secret agent) of these nefarious devices...known from this point on as "the perps":

* notice the carbon blocking the devices' intake side opening...

* both devices surreptiously holding hands?...or "your tea sir"...

> pictures should have been taken on a neutral background...rather than a white one..duh?

This is some additional info that might help with decisions and save some time when you do this job.

* You need a manual with the EGR diagnosis & tests...it's a very good idea to check vacuum line routing around the EGR and the vacuum modulator...and also lines anywhere that might effect the vacuum to them...this includes most lines?

Check under the hood for the vacuum line routing sticker.

* Since you will be dealing with parts that are heated by exhaust gases...it's best to hit the different areas with a penetrant several times for at least 24 hours prior to starting this job.

These include...

- the (2) bolts that hold the EGR (12 mm 6 point socket)

- exhaust tube at the EGR (24 mm open end wrench)

- exhaust tube at manifold, front of engine (19 mm socket)

* The vac modulator is held by spring clips

* You might want to label or replace the vac lines as they are removed

* The fittings on the exhaust tube can be a little difficult to get to...the one at the EGR might be loosened from underneath the easiest. This fitting needs to be taken completely loose...while the one at the manifold just needs to be loosened some.

* The two bolts that hold the EGR came off fairly easy...hope for the best. Toyota seems to cadmium plate most bolts or studs to avoid rust problems.

The actual cleaning:

* I didn't find anything that would really loosen or dissolve the carbon...I tried a strong detergent type cleaner and soaking the lower part of the valve in acetone...but only for an hour or so. Not sure they helped at all.

* Very likely...using a penetrant or some kind of solvent for several days at least...MIGHT make the job easier.

* You need to be very careful of the diaphram at the top and need to keep strong solvents and sharp objects away from it. Check the cost of an EGR valve above?

* I removed the steel tube from the EGR that goes to the vac modulator...I used vicegrips on the head of the screw. You need to do this in order to get at the carbon inside.

Stuff I used to clean the EGR....

- coat hanger wire (curved at end)

- thin steel wire (curved at end)

- pointed awl

- small screw driver

- battery terminal wire brush

- water from hose...high pressure

* Most carbon collects on the intake side of the valve...I just started chipping away with a small screwdriver...either knocking loose carbon out or spraying it out with water.

This process takes patience. I used a vacuum pump tester to apply vacuum to the diaphram to move the valve up and down (apply no more than 5-6" Hg?), and to test by blowing air into one opening....to see IF the valve was clear. Or better to use water under pressure to avoid a dirty face?

It was only by keeping at it that it finally cleared out at the valve itself...then I used a fine wire (curved at the end) to try and clean the area around the actual valve as much as possible.

* Also, there will be some carbon in the intake manifold opening...best removed using a battery terminal brush.

* Once the EGR is cleared...the old gasket needs to be removed...not too easy.

Reinstalling the EGR:

* I used moly grease on ALL bolts and fittings, including the small steel tube on the EGR.

* Installation is basically the reverse of removing it...but be sure the vac lines go back on right. Don't overtorque anything.

Testing notes:

* For the EGR vac line test with engine warm and at 3000 RPM I got a reading of 3" Hg. Saw that the EGR valve opens fully at around 4" to 5" Hg.

* I didn't test the TVSV...the test above says the EGR works. I think.

Final note: Seems that a functioning EGR might cause a loss of 5% in "power" and maybe 10-12% in MPG. This result is from testing thru 3 tanks with the EGR working and 4 with it not working (and with my current mods...advanced timing and heated fuel). The new exhaust didn't seem to affect the MPG much. You do need a working EGR to pass emissions?

sacwac · Post by **sacwac** » Mon May 31, 2004 5:07 pm

Great job! Isn't it amazing how tough that carbon build up is? How far into the egr was the carbon?

Also, did you notice how when you apply vacuum to the egr when it's idling, the engine runs rough, or dies? That's another way to test the egr. I think thats in the manual too.

takza · Post by **takza** » Tue Jun 01, 2004 3:44 am

Mine had pretty much solid carbon from the intake opening to the actual valve part....the carbon right at the valve itself was the last to go...and it came out in solid chips. On the exhaust side it was more or less clear.

The valve area itself is difficult to get to...needed to force curved wires into that area to get to the carbon.

It's possible that soaking in acetone or similar overnight might loosen it up...I only let it go for a hour or so....but you don't want the solvent getting to the diaphram though.

Sacwac.........it makes sense that a good penetrant might work the best to loosen the carbon.

Tried the vac to the EGR test at first and it failed. After cleaning it, I used a hand vac pump and water hose to see that there was a good flow when vac was applied.

Now have a high idle around 1500 RPMs...looks like the fast idle adjustment is off...

Guest · Post by **Guest** » Sun Jun 06, 2004 6:02 pm

I've been working on cleaning mine, I let it soak in a cheap solvent for a week and it made it a lot easier to get the carbon out. Mine was plugged on both sides pretty badly. If you have and air compressor it helps to blow out the carbon and the solvent, then you attack it with a pick or wire for a bit and then hit it with the air again, repeat as necessary. I've reached to point where I can get the valve to move but I'm still getting carbon out. Oh and its not fun

Thereminator · Post by **Thereminator** » Wed Aug 25, 2004 9:11 pm

So Takza,what does a de~carbonized EGR Valve do,increase or decrease fuel consumtion? Do you think soaking the non~diaphram area in Berrymans carb~cleaner overnight would help? Why do you use molly~greese on your re~install bolts?

Fingers · Post by **Fingers** » Fri Aug 27, 2004 1:01 am

Passed emissions with a fully clogged EGR, actually fast passed(super low ems). Engine at normal operating temp, clean oil, etc., etc.

So, no I guess you don't have to have a working EGR to pass, but then again, it was a frsh engine. I'll let you know how it goes in another year and a half or so, with 40,000+ miles on it(unless I finish rebuilding this carb and replace it).

takza · Post by **takza** » Fri Aug 27, 2004 3:38 am

EGRs are a conspiracy by somebody...not sure who though. :unsure:

** Finally drove the car with the new O2 sensor and the EGR enabled...when it got warmed up...there was some serious bucking and hesitating from idle up to around 1500 RPM and the idle was low and poor.

After disabling it again...the car idled pretty well and the bucking problem was gone.

Before replacing the O2 sensor, the car ran OK with the EGR enabled...just had less power and got less mileage.

So a functioning O2 sensor affects the EGR (apparently makes it put more exhaust into the manifold). Maybe one of the many "gizmos" isn't working right....allowing too much exhaust gas to recirculate.

At any rate it is OFF again...and if it isn't needed to pass emmisions...causes a loss of power...and MPG....then maybe Toyota will buy it back for $200 or so?????

takza · Post by **takza** » Wed Sep 01, 2004 5:12 pm

Thereminator wrote: Why do you use molly~greese on your re~install bolts?

It's an easy to find anti-seize material...have since found my tube of REAL anti-seize stuff...so I'm using it again on the real important stuff.

I had an older mechanic recommend the moly grease when assembling exhaust/manifold bolts and so forth. Most people have some moly wheel bearing grease around.

Lateer · Post by **Lateer** » Wed Sep 01, 2004 7:10 pm

A mechanical engineer explained the use of molybdenum grease on bolts to me.

He said (and I think he's right) that the torque force you put on the bolt to make it turn can shear the bolt if you tighten it up too much.
The grease reduces the frictional force between the threads, meaning that it'll tighten up easier and allow you to tighten it further than you could without it before the bolt binds and shears.
He said to not use a whole hell of a lot, and not on the head of the bolt as you want somewhere to prvide enough friction so the bolt stays done up.

The feller now helps build and maintain power station turbines, so I think he's onto something.

Eatpants · Post by **Eatpants** » Thu May 05, 2005 9:07 am

i cleared the path from where the pipe comes in and the little pipe up to the vac modulator but i can not clear the other path, ive gotten it to take a little bit of air but ive been working at it for 5 hours since then to no avail....

just going to put it back in before i get pissed off and throw it off the cliff

do i absolutely need a new gasket? probably yes since i chipped this one a little (how the hell do i get the old one off)

someone help me out?

takza · Post by **takza** » Thu May 05, 2005 6:52 pm

I'd give it another go after a break?

That gasket is the toughest POS I've ever removed.....maybe some high-temp silicone stuff would fix it?

clbolt · Post by **clbolt** » Thu May 05, 2005 8:39 pm

takza wrote: It's an easy to find anti-seize material...have since found my tube of REAL anti-seize stuff...so I'm using it again on the real important stuff.

You're not still buying anti-seize in the little tubes, are you? The jar with the applicator brush is available at most auto parts stores for about 4 bucks, and will last for several years (more like a lifetime for the average DIYer). That stuff is an absolute necessity for spark plug threads in anything with an aluminum head.

My Grandfather (who was born in 1894, and who worked on the first car in his town) showed me how to change spark plugs when I was 11 years old, and he always used a little motor oil on the threads. Of course, he never owned anything with aluminum heads.

takza · Post by **takza** » Fri May 06, 2005 3:57 am

I have a small tube of the copper-based stuff I found on sale. If I see the jar you are talking about I might go with that.

As far as using the grease on bolts...I have used it mostly on exhaust or other obviously rusted bolts or on anything small in a rusty area...saves a bit of grief the next time thru. Like the bolts that hold the splash pan.

DON'T use it around anything important when assembling engines...trans...etc. Except for exhaust.

If I do use it...I'm real careful about the torque I use...staying on the LOW side.

takza · Post by **takza** » Mon Sep 04, 2006 6:46 pm

Might have my EGR working....finally.

I tested the EGR itself by applying vacuum and having it stall the engine.

Now have the vac modulator hose hooked up to it and the car now drives OK.

Will have to put a tee into the line going to the EGR from the vac mod and drive the car to see if the EGR is actually getting some vacuum while moving.

I injected some WD40 into the ports of the vac modulator previously to try and free up the valves inside...might have worked....