EGR Modulator (1 Viewer)

[MLX450]

I wanted to add these pics to somebody's thread, but couldn't find one so.... if you wonder what it looks like inside here goes..... I replaced this a year ago to clear my P0401 with the blue top modulator. You can see the damaged diaphram. Also added a pic of the VSV for the egr.

 

[Rich]

How many miles on the failed modulator at the point in time you replaced it?

 

[MLX450]

about 120K (i purchased it with 118K) now i got 131K.

 

[4x4CPOSEADOG]

ML, is that your name on the special order tag? Are you a pinoy by chance? Thanks for showing the picture of a VSV, now I know what it looks like.

 

[MLX450]

yup

 

[landtoy80]

I am glad you posted the pic of the modulator. It shows how when the modulator goes bad, it lets carbon into the vacuum system, thus the carbon plugs the VSV.

 

[MLX450]

your welcome. It was just in my garage when i decided to rip it appart and post it here. this site rocks

 

[rolliges]

Bump

Great pics of inside of EGR modulator.

Shows why carbon under the filter indicates system failure!

Very useful information.

Just for reference here is my EGR modator:

 

[landtoy80]

I am on my second modulator and VSV.
The first one went bad at around 200,000 miles.
The second one was replaced around 270,000 miles. I did not test the second pair but a Toyota dealer did as I had no place to test them but it did clear the CE light and lowered emissions.

My theory back when mine went bad years ago is that the modulator diaphragm cracks and lets carbon get into the vacuum system and carbon gets stuck in the VSV. So if the one or the other goes bad you may as well replace both.

 

[NLXTACY]

If you ha e to replace the VSV, it's a good time to relocate it to someplace where it isn't a bitch to get to.

 

[landtoy80]

If you ha e to replace the VSV, it's a good time to relocate it to someplace where it isn't a bitch to get to.

If I have to replace the VSV again, based on how often I have changed it, it will have about 550,000 mi on it...I hope to afford a newer LC before that happen. But if i still have it it will look much like this.

And yes that Turdvalanche' is part FZJ80. The top and bottom support beams are the factory running board from my 80. So this is 80 Tech and not chit chat.

 

[NLXTACY]

I'm on my third. Just saying.

 

[landtoy80]

Wounder if there is a way to put a filter on the vacuum line to filter out any carbon that may get into the VSV.

I am ASSUMING that its carbon that is messing up the VSV. The VSV is a tiny electric magnet with a diaphragm that opens and close the vacuum line.
Yes relocate it if you can but a filter could solve the problem.
One chunk of carbon would be enough to break the seal on the VSV diaphragm and cause a vacuum leak. If you have not taken apart the VSV and hooked up a battery to it, do so. Its neat how it just goes up and down.

Next time you replace the VSV make sure you blow out all the vacuum hoses to get any carbon stuck in there out. I would say to remove all the hoses and blow them out and inspect any of the junctions between the modulator and VSV.

 

[NLXTACY]

Yeah I actually changed out every single vacuum hose in the truck with the engine rebuild last month. Shouldn't have an issue now for a very long time.

 

[rolliges]

I like the idea of a filter before the VSV. And will relocate to the fender as per Beowulf and/or Raventai did in an old post.

Relocating will keep the part cooler. Heat seemed to contribute to VSV failure based on Raventai's very thourough troubleshooting.

So: heat destroys the modulator diaphragm and then carbon travels downstream to clog the VSV if heat hasn't already effected the VSV's diaphragm.

Know we all know a lot more than before.

 

[kotikofwar]

got my first 80 a week ago and got a P0401 today... sort of bummed already having issues not even having it that long. PO rebuilt the motor, noticed a lot of the vacuum lines weren't replaced, wish they were sine some of them do look old and starting to crack. The EGR thing looks lie it may have been replaced, will have to check w/PO on that, cleared a code to see if it was a fluke or if it'll come back again. Any say of how soon the light will come back on if EGR or VSV (which I still don't know what it is or where it is yet) are bad. Also I wonder if there could be any relationship of that code to filling up with Costco 89 octane since it happened 10 min after I put gas in it. (it does see m to just go trough gas... hard to calculate exact mpg yet)

 

[ARB777]

If the diaphragm is cracked up like that and i did the egr hairpin bypass on a 94 but did not block off the egr pipe, could it cause extra air going in that eventually causes a lean code?

 

[buxton]

G