Carbon in EGR Vacuum Modulator

[Tentsontop]

I'm consistantly getting carbon (little granules that look like smokeless powder) in the bottom port of my modulator. I also have condensation (water) in the modulator. I'd like to take off my EGR valve and give the tube below a good cleaning. How do you get that huge nut off?

 

[Beowulf]

Robogrips is what I used.
-B-

 

[Tentsontop]

I've always wanted a pair of those. I'll pick them up tomorrow!

 

[IdahoDoug]

Chado,

Don't get too excited to do this, as the big tube is not likely restricted to any degree. I don't think anyone's reported any clogging in that tube, because it is quite hot. The clogs occur later in the smaller tubes because they're cooler, and well - smaller.

Also, it can be a serious bear to reattach, and one final caveat against is that mine snapped on removal - the actual thick cast metal large part of the valve base snapped. So, you're doing something that's tough, is unlikely to provide any benefit and in the end may cost you $ and serious aggravation if it snaps.

Just my 2 cents.

DougM

 

[Beowulf]

Chad,

While I answered your question, Doug gave you the best response to your post. There is NO WAY that big tube is clogged up or contributing to carbon in your EGR modulator.

Have you cleaned the tubes and hoses we discussed via PM? Have you replaced the VSV for EGR? Those are much more likely to be the cause of your P0401 than the EGR valve itself.

-B-

 

[Tentsontop]

My new VSV and modulator are on the way and should be here tomorrow. I have a second engine from my 93 sitting as a model. I pulled everything on it and there was zero carbon to be found. It has more miles on it than the one I'm working on now. I don't get how some engines are prone to this when others seem to never have carbon problems.

After looking at the 93 I pulled the modulator off to see what it looked like and the lower hole was completely full again. I cleaned it and the rubber hose that connects to it last week. If the granulated carbon is not coming from that big tube where is it coming from?

 

[ronin-0707]

sorry to hi-jack, does the egr vacuum modulator cap just pops off? can this be done by hand?
too scared to give it a good tug.
do you clean the filter with just compressed air?
thanks

 

[Tentsontop]

Yes to both.

 

[IdahoDoug]

Chado,

-Driven around town exclusively? If yes, take 'er for a freeway spin 30 mins
-Using crap gas? If yes, stop it.
-Been awhile since new sparkplugs? If yes, change 'em.
-Been using oil/fuel additives? If yes, stop.
-Ignition timing correct? If not, adjust.
-Less likely, but do you have a good thermostat - bad can make engine run too cool.

DougM

 

[Tentsontop]

The answer is yes to the majority of your questions especially the cheap gas. I do romp on it (75-90) to/from Denver and I only use a couple cans of BG44k once every four months. I'm going to clean all the hoses this time and use the old modulator until I'm sure the carbon is gone. The plugs are only about two years old. It runs like it should and gets about 15 mpg so I wasn't too worried about plugs. I'll change them too for good luck.

 

[Rookie2]

I only use a couple cans of BG44k once every four months.

Only??.... That seems like a lot to me.


Rookie2

 

[SOCALFJ]

Careful removing that nut on the back tube. I just had my EGR Valve replaced and the nut sheared off the top of the tube thread. They had to replace the tube.. and it's NOT FUN.

 

[Tentsontop]

Only??.... That seems like a lot to me.


Rookie2

You're prolly right. I use 4 cans on average per year on each vehicle depending on tank size. I also Seafoam them once, use BG's oil additive with each oil change and their oil system cleaner once every two years. As I said before, the 93's engine has ZERO carbon. The new to me 94 and 97 have not been part of my usual routine and are my snot nosed kids right now.

Careful removing that nut on the back tube. I just had my EGR Valve replaced and the nut sheared off the top of the tube thread. They had to replace the tube.. and it's NOT FUN.

I hear you and Doug loud and clear. I'm not going to take the EGR off unless I have to.

 

[CJF]

See if you can blow air into the bottom port of the modulator. If you can it's toast.

 

[Tentsontop]

I've got a good and a bad modulator. The bad one I can blow air into from the bottom. I've seen pics of modulators with carbon in the top or in other lines. I only get it in the bottom line. My new modulator and VSV are here so I've got some more cleaning/testing to do before I install them.