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The filter should be just to the rear of the intake manifold #3 runner, as shown in porcupine73's first pic.

It's certainly there on my own '99 OBW.

 

Maybe mine's just really dirty. I will look again.

 

My mileage is still about 25 mpg. I've gone to AutoZone and have had them clear the codes a few times. I've gone thousands of miles before it came back on. Last time, however, I got about 20 miles before it came back on. There is no noticable difference in the way the car sounds, drives, or feels. Just that dang light on all the time...

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I'm not sure if this is the filter, but was the only thing that looked like it might be something like that, circled in red, is this it?

filter1c.jpg

 

Also I imagine these metal lines crossing under the throttle cable are the ones the endwrench article says they have seen plug up or rust out

egr96-2.jpg

 

I think thats a check valve / vac has to reach a certain hg before it opens.

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I'm assuming that the code is the same PO400 that I have been getting all along. I checked the vacuum hoses and blew out the filter thingy like the other guy did, and reset the error codes. The light stayed off for about 75 miles and came back on. Just wondering what I should check next.

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The CEL came back on today. I'm found one cracked vaccum hose and "fixed" it. I probably have other cracks that I can't see. I'm going to get a bunch of new hose and just replace all the old vaccum hoses. They're hard like plastic now.

 

Dumb question... is there any need to use the steel line sections that go under the throttle cable? I'm thinking it would be safer and easier to eliminate these possibly rusted and blocked lines from the vaccum system.

 

I'll run the new rubber lines OVER or behind the throttle and use zip ties to keep them away from moving parts.

 

egr96-2.jpg

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The CEL came back on today. I'm found one cracked vaccum hose and "fixed" it. I probably have other cracks that I can't see. I'm going to get a bunch of new hose and just replace all the old vaccum hoses. They're hard like plastic now.

 

Dumb question... is there any need to use the steel line sections that go under the throttle cable? I'm thinking it would be safer and easier to eliminate these possibly rusted and blocked lines from the vaccum system.

 

I'll run the new rubber lines OVER or behind the throttle and use zip ties to keep them away from moving parts.

 

egr96-2.jpg

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Hi. I think the factory vacuum lines are purposely kind of hard to keep them from collapsing under vacuum. If you have a lot of vacuum type leaks, one of those smoke emissions system leak detectors can be useful in finding the source. I've been meaning to build a diy one but haven't gotten a round tuit yet; the commercial ones are a few hundred $ on up.

 

I'm guessing the metal lines there are just to keep the routing away from any potential hang up in the throttle cables.

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thanks PC73!

 

I replaced most of the lines today with some good quality stuff. Just for kicks, I blew through the metal lines under the throttle cable. One of them had quite a bit of liquid in it. Possibly water? I'm guessing it could have easily froze and restricted the air flow through the line. Also replaced the PCV valve (the old one seemed fine though) and reset the code by unplugging the battery.

 

I blew and sucked on the EGR vaccum hose and could hear it opening/closing. I'm assuming it is fine.

 

Will fill up the gas tank and check MPG again. Hopefully it goes up from its current 14.5 mpg and the cel stays off! Weird thing is... the car always starts and runs fine... even with the cel on and the po400 code.

 

On the passengers strut tower there is a device that has a 3 prong electrical connection and 1 vaccum line going to the bottom of it.

 

What is that?

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porc - rubber gets hard over time. Vac hoses are soft (flexible) but thick walled to prevent collapse. In reality even IF the vac hose collapses, it doesn't "matter" since it was vac that collapsed it and vac is what you want. :) It will pop back out once the vac is removed, anyway vacuum hoses don't carry anything except "vacuum" (which is a lack of air) ;)

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[...]In reality even IF the vac hose collapses, it doesn't "matter" since it was vac that collapsed it and vac is what you want. :)
A little respect for "vacuum", please. :)

 

Under many circumstances, it certainly can matter if a vacuum hose collapses. If the collapse were total, the device connected beyond it (sensor, actuator, etc.) would no longer "see" the "vacuum", or more specifically, any changes in it. If the collapse were partial, change would be seen, but the response time would be slowed (to what degree would depend on just how narrowed the opening was).

 

Furthermore, "vacuum" is sometimes intentionally bled off in certain devices, and if the source hose is blocked, would not be replenished at the expected rate.

 

 

It will pop back out once the vac is removed, anyway vacuum hoses don't carry anything except "vacuum" (which is a lack of air) ;)
Although it's the term that's commonly used, of course the "vacuum" in those hoses is just air at pressure lower than atmospheric; it's not anywhere near a true (absolute) vacuum. What the hoses carry is that lowered pressure, and depending on what it's routed to, the actual measure is information that may be important to the function of a system.
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On the passengers strut tower there is a device that has a 3 prong electrical connection and 1 vaccum line going to the bottom of it.
I believe that may be the pressure sources switching solenoid to allow map to measure barometric pressure? Not sure for sure.... sounds like your vac hoses were very brittle. Mine are pretty brittle too.
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well, now... in "normal" hoses designed to carry vacuum (in automobiles) the wall thickness is enough to actually prevent collapsing unless the hose itself is actually kinked and blocks the vacuum beyond the bend. As to actual vacuum, engine vacuum typically gets to around 22 inches hg or so so the vacuum is a lot less than 29.97 "normal atmospheric". I've worked with vacs close to "zero" in the semiconductor industry. :)

 

The problems occur when the HOSE is NOT for vacuum - just gets put on because it's the right diameter (like a vinyl hose) :)

 

Busa - sounds like the OEM vinyl rigid "hoses" - Chrysler used to put on the rigid hoses (pipes) with rubber ends to make the connections because the pipe was cheaper than the hose. Vinyl does get pretty brittle, though and finding a "crack" is not an easy task either. From what I saw on the 97 Impreza I'm working on, the hoses are pretty rigid as well but not brittle. I just wonder if they are "metric" or not.

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well, now... in "normal" hoses designed to carry vacuum (in automobiles) the wall thickness is enough to actually prevent collapsing unless the hose itself is actually kinked and blocks the vacuum beyond the bend.
True, but my comments were based on your statement that ' IF the vac hose collapses, it doesn't "matter" '.

 

 

As to actual vacuum, engine vacuum typically gets to around 22 inches hg or so so the vacuum is a lot less than 29.97 "normal atmospheric".[...]
Okay... to simplify the math, let's call atmospheric pressure 30 inHg. That means a gauge reading of 22 is equivalent to 8 inHg absolute (30 minus 22). Throttle opening and closing, especially if rapid, can cause gauge measurement as low as "0" or as high as about 26; the equivalent absolute would be about 30 to 4 inHg. Anything that prevents or delays the engine management system "seeing" the variations (other than intentional restrictions, "orifices") can lead to poor drivability.

 

 

The problems occur when the HOSE is NOT for vacuum - just gets put on because it's the right diameter (like a vinyl hose) :)
Agreed, that's a bad idea. I've seen it done, and cause strange symptoms. The car would run okay when cold and even during warmup, but problems developed when the engine was hot enough. If allowed to cool down, it ran fine again. The difficulty was due to softening of the vinyl hose and vacuum collapsing it. When the engine was shut down, the lack of vacuum allowed the hose to regain its shape, and cooling stiffened it until the next run. It was a short piece, and apparently whoever used it thought there wouldn't be a problem; naturally, it was "buried" beneath the intake plumbing, making it hard to spot. "Fun" :rolleyes: .
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For the record, I got my vac hose from advance auto. It has really thick walls.

 

While removing an old hose on that little electrical/vacuum thing on the passengers strut tower, I broke off the plastic nipple. I did super glue it back on but when blowing or sucking on the nipple there was no noticable air going into or out of it. I was pretty careful not to get glue in the hole but who knows.

 

That this is a selonoid activator?

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