Valkyrie

...I'm confused as to why my split air hose is SUCKING air instead of blowing it out.

...seems that might explain the ECU code but I can't imagine why it would do that? The check valve was OK from what I can remember, but all that does is keep air out of the exhaust ports...

My AAV's diaphram is probably shot...

But I can't imagine what would cause the solenoid to suck air (the solenoid itself actually works).

HAILERS

What year and type of car? Series five and turbo or non turbo?????

Which check valve????????? The one in the Split air pipe or the one b/t the ACV and the manifold?????? The one b/t the ACV and the manifold is to let air go to the exaust ports and keep air from the exaust area coming back into the ACV.

Your talking abou the Split Air Solenoid that screws into the ACV?????????? What did you do? Remove it and feel around the hole and felt vacuum with the engine running?????

AAV is the anti afterburn valve which is internal to the ACV. It can be *disabled* so it won't leak air into the intake when it should not.

Valkyrie

It's an NA S5...

Air was being sucked into the split air pipe itself (on the S5 it's big enough to fit your finger into...). Not all that much but it's still going the wrong way.

I'm missing the split air pipe itself but the large rubber hose that connects the main metal pipe to the engine is still on it.

The check valve I was referring to was the flat disc-shaped one that keeps exhaust fumes from coming back through the ACV.

I know I can disable the AAV... I just hate wasting the gasket I just put on the ACV a month ago...lol

I removed the valve and took out the spring and valve to see whether that would stop it from leaking... although I figure it'll probably actually make it worse.

I'm also trying to get the relief silencer from making such a racket... I think the reason it buzzes like a **** (less so with my homemade silencer, but it still makes the engine louder than it should be) is maybe because it's sucking in more air than it should be, and isn't pushing it out the right ports.

I confirmed my solenoids were piping to the right hoses...although I don't know which nipple they were connected to.


Which nipple is which on the ACV? I sucked on the top left one to check for leaks and I could feel a valve or something being opened, and then closing when I let the vacuum go. I didn't check the other nipple because, well, it's a PITA...

Was the top left one the switching valve or the AAV? What is the lower one (that's clamped and sticks straight out), and what's the top right one?

skiallday

the reason for the sucking is probably becasue its a vacuum tube. but i dont know what for or anyhting.

i dunno how this could be so amazing to you but for future refrence a vacuum is an area of lower pressure. lol

Valkyrie

...the split air hose is supposed to *blow* air... unless I'm horribly mistaken :p

Valkyrie

Also, what holes should you plug with RTV on the S5 NA ACV? The S4 NA's ACV (the picture you posted) is similar but the S5 has bigger orifices and such... Is that mushroom-shaped thing on the top the AAV? If so I can make a reasonably good guess as to which whole to fill.

HAILERS

I've never seen a Series five or its ACV.

But they work the same as series four.

On a series four, there are two vacuum hose just above the ACV but NOT a part of the ACV. The series five should be the same.

How to figure out, which of the two is the Relief vacuum hose can be done. First the engine NEEDS to be fully warm/hot.

EDITED WHAT I originally wrote. It was *** backwards. I'll write back later, I'm busy.

HAILERS

BACK: Look, both the small hose above the ACV should be pulling vacuum when the engine is at idle and the engine is warm/hot.

Pull the Blue plug off the Relief Solenoid. When you do that one of the two small hose mentioned above should lose its vacuum. THAT will be the Relief solenoids vacuum hose.


Now pulll the LARGE hose off the bottom of the ACV. Look inside with a mirror and flashlight. Suck on one of the two small nipples above the ACV. When you suck on the right nipple you'll see the valve in the LARGE nipple on the ACV move. When you see it move when putting vacuum on one of the small nipples, then you've just ID'd the small nipple that should recieve the vacuum hose from the Relief solenoid.

The other small nipple will of course be the one for the Switching solenoid.

Take note that the switching and the relief solenoids are set up different. The relief solenoid has its small filter next to its electrical connector. The switching solenoid will have its small filter at the OTHER end of the solenoid, away from the electrical connector.

Those solenoid work *** backwards from each other. The Relief when energized passes air from point A to B. The switching solenoid passes air from A to B only if de-energized.

At idle, if the tps is set right, the Relief will be energized and the Switchind de-energized.

Another way to see if the ACV is worth a hoot, is to plug both small vac hose above the ACV. Then put a spare hose on one or the other nipples above the ACV. At idle suck on one or the other hose. When you suck on the right hose, no air will be expelled from the botom of the ACV. That will be the small nipple for the Relief solenoid.

Or try this at idle with a warm/hot engine. PUll the big hose off the bottom of the ACV. Little to no air should be coming out. Now pull the BLUE plug off the Relief solenoid. NOW a large amount of air should come out the bottom of the ACV. Put the Blue plug back on and the air should almost cease coming out the bottom of the ACV.

Valkyrie

Well, according to the diagrams it's the left one. The one on the right is the switching valve.

Blowing through through the hose on the solenoid's side of the rack confirms this.

I couldn't actually confirm whether the diaphragm was leaking because the only boom-tastic spray I have with me is WD40, which doesn't really lend itself for use in testing vacuum leaks, since it just wants to stay as a liquid. But I could only imagine it's leaking seeing as how the idle drops when the relief solenoid is off... (...circumstantial evidence...)

I've already RVT'ed the holes I'm 99% sure go to the AAC. It's just that the lower of those two holes is much bigger on the S5 so it took a bit more RTV than an S4 would have taken. I'm gonna put it back on as soon as I feel the RTV is hard enough.

I also can't find a reason as to why the split air hose is pulling vacuum...


I also noticed that simply blowing through the 6PI solenoid's output nipple with a peice of hose, and pulling on the actuators is a very good way of seeing if they function... seeing as how the solenoids are basically bulletproof (and the ECU would tell me if they weren't working, outside any air blockages). The same thing works for the VDI.

Seems like a simplier, quicker way of testing them than smearing grease on the rods... since if the vacuum hoses are going to the right place it's basically a given they're gonna work, if they move.

HAILERS

Seems like a simplier, quicker way of testing them than smearing grease on the rods... since if the vacuum hoses are going to the right place it's basically a given they're gonna work, if they move.(((((((((((((((((((((((((((((((((((((((

It is on a seried five. Either that or couple the two hose on the solenoid with the engine running (airpump still on the engine).

Or on a series four just blowing in the hose connected to the aux port feed line.

Valkyrie

Apparently filling the ports that (probably) went to the AAV didn't make a damn bit of difference. The idle still drops when I pull the relief solenoid connector, meaning there's still a vacuum leak SOMEWHERE...

And I think the air relief valve may have got even louder...

After I came home from work (it idled crappy all the way home), turned the car off (so I could open my door), and turned it back on, it started idling beautifully until I pushed on the brake a bit. Then it dropped 200 RPMs and started pulsing, even worse than it did on the drive home.

I guess the only thing left to do is hook the intake up to a compressor...

Maybe I should make the end cap out of wood instead of searching fruitlessly for a PVC end cap that either has a 3 3/16" OD or a 2 9/16" ID...

Perhaps my problems are partially due to the AFM?... perhaps the air temp gauge is out of allignment (I checked it and it didn't seem to be), or maybe the spring is worn out and isn't corresponding to the correct flow amount any more (is the resistance pattern on the cone's variable circuit supposed to start at like 500, go up to 1500, and then drop straight to like 200?)... it sounds like there's a spring or a broken wire lose inside of it.

Also, what in the drivetrain would make a thud sound (that sounds sort of like afterburning) ever time you let off the throttle and get back on it, but only while driving forward, if it's not afterburning? Diff mounts perhaps?

...problems, problems, problems... well, at least it drives.

(the split air solenoid still don't seem to be pushing any air out... I didn't confirm whether it was still sucking air though.

HAILERS

****Apparently filling the ports that (probably) went to the AAV didn't make a damn bit of difference. The idle still drops when I pull the relief solenoid connector, meaning there's still a vacuum leak SOMEWHERE...***********

Buy a can of starter fluid. Pull the inlet hose to the airpump off. Start the engine and let it warm up. Spray for a second or less in the airpump inlet. IF the engine speed changed, then the AAV is bad in the ACV. There is no other passage to the intake other than that AAV.

*******Also, what in the drivetrain would make a thud sound **********8

Possibly the fwd mount on the rear differential. Or the driveshaft u-joints. Put the rear of the car on car ramps. PUt your hydraulic jack below the front part of the differential. Jack the jack up and watch the front of the differential. The nose of the differential should move upwards ALONG WITH the chassis. If the nose moves up and the chassis does not, then the front mount on the differential is busted.

Other things cause a thud other than the fwd mount on the differential. Those camber links on the left and right sides of the rear end can cause a thump. I've no proven method of checking them.

***********I pushed on the brake a bit. Then it dropped 200 RPMs and started pulsing, even worse than it did on the drive home.**********8

Not sure about that. Check and make sure the brake booster line at the engine is on tight and that the line to the brake booster is not leaking. Also make sure the brake booster itself is not leaking. How??? Got me

Seems the bac would make up for that load you put on when you put the brakes on. Idle the car fully hot. Pull the bac plug off as it idles. The idle usually drops a touch , but not enough to cause the engine to die.

If it dies, then it's back to square one. Set the timing, set the TPS, set the idle speed to approx 750 with the initial set coupler installed OR pulling the bac plug off and setting the idle to 750 without installing the initial set coupler (better method imho).

Valkyrie

Pulling the BAC off doesn't effect the idle.

Usually that indicates a vacuum leak... as does not being able to make very precise adjustments to the idle.

It hasn't actually died from a low idle at all (besides a few freak misses in traffic, usually from a very cold start)... but it's running rough.

I already blocked off what I'm fairly sure are the AAV's passages to the intake manifold, so I don't see how it could still have a leak (although obviously it does if it fails the starter fluid test... I'm gonna wait till I go home since I already have a few cans of it there).

The only other places I can really suspect perhaps vacuum leaks I never fixed to begin with (perhaps one of the old, hardened vacuum caps is no good, or maybe a gasket is bad, namely the UIM since that's the last thing I took off before I remember these problems started), or one of the vacuum hoses under the UIM (like the big one for the AWS). The LIM manifold is re-useable IIRC, so I can't see why that would be a problem, although I did take it off once... that's when my thudding/popping sounded though (after fixing a vacuum hose when I put it back together).

I think I might also have an exhaust leak (probably from all the backfiring), which can apparently affect idle... so I need to fix that as well.

And perhaps the pressure sensor has become temperature-sensitive do the being old...apparently that can happen to cars. I honestly can't see why the pressure would be different simply due to temperature (the AFM is different, of course).

Valkyrie

Backfiring from revving out of gear seems to have increased...

I checked the actual vacuum numbers and they were damn good...except they were fluctuating due to the fluctuating idle (which seemed to be caused by a vacuum leak... I think my relief solenoid was in OFF mode because pulling the connector didn't make it any worse).

There definitely seems to be an exhaust leak as I can smell it and sort of see it.

At least two of the vacuum caps are pretty hard and need to be replaced just to be safe.

Also, I tried checking the vacuum pressure sensor again, since it's cold now, and there were some strange fluctuations in the voltage when the hose was off the manifold (exposed to outside pressure) and when I was trying the suck test.

I'm pretty sure the sensor's voltages weren't nearly as inconsistent when it was warmer outside, so maybe there really is an issue with sensitivity to cold. Strangely the resistances of the sensor weren't inconsistent at all, so maybe it's an ECU issue? I wouldn't imagine the ECU itself is sensitive to the cold, but maybe it was effected by info from the air temp sensors...

I'm gonna get a vacuum hose and bypass the relief solenoid to see if that causes it to behave like it's always on (meaning, no idle drop when you pull the connector).

I think I'll also try leaving the sensor inside my room (maybe putting it next to the heater) and seeing if there's a temp sensitivity based on the temp of the sensor, or the temp of the air hitting the sensor. This seems possible since how could the temperature of the air actually being measured by the sensor affect the sensor? It's *vacuuum* after all...


Also, my vacuum gauge was indicating less than 0 vacuum (meaning it was showing like .5 PSI of boost) with high throttle... I wonder if this is just an issue with the cheap gauge, or if something like the air pump could cause this? (as unlikely as it is)

I think part of the idle problem *may* be that the ECU occasionally seems to ignore what the vacuum sensor is doing (probably AFTER the light has come on once), and when the vacuum sensor isn't working, that usually hurts the idle as well.

And finally, my negative battery terminal has become kind of lose (it's all bent up from being tightened so many times and won't get any tighter), so I need to replace that too (again).

Valkyrie

Looking again at the FSM, those may have not been the right voltages for approximately 3.9 in hg of vacuum (applied via my mouth...). I think it was 3.8 (and sometimes higher, up to 4) at atmospheric and 3.5 with approximately 3.9 in hg... less with more vacuum is applied.

When it's warmer out it was well within the specs, iirc...

Valkyrie

I bypassed the relief solenoid. Idle is much better now...

Also, the split air hose is finally BLOWING air instead of sucking it.

But the silencer hose is still pretty loud... I think it might have got a *little* quieter though.

The BAC still isn't working though.

It was working just fine when I checked it months ago (it wasn't stuck, but I cleaned it anyway). And it's not throwing a code, so to me this sounds like a vacuum leak. The idle still drops a bit when you put on the brakes, and right now it's maybe at 700 and won't go any higher (unless you give it a bit of throttle, which will cause the timing to advance for a few seconds)... the primary injectors may be suspect because they're missing the spacer that's required to have them bolted down properly...

Whatever... I'll find/fix the vacuum leaks when I go home... and the exhaust leak... and the oil leak... if I have time, and the parts get there fast enough.

HAILERS

I was confused about the spacer but I know what your talking about. The oval shaped spacer b/t the primary rail and housing. You could use two flat washers b/t the rail and the bolt holes to even thiings out. Its possible the lack of a spacer MIGHT cause vacuum leaks because the injectors grommets MIGHT not be sealing.

If a idle is in the 750 or LESS range, pulling the BAC'S plug off should result in a touch lower idle speed IF the BAC is working right. If the idle speed is over 750rpm its unllikely the engine speed will be effected at all if the BAC plug is removed.

Valkyrie

I'm gonna pull the BAC off again and check it out this weekend.

Also, I happened to have my windows down and I noticed the popping sound does sound significantly more like a backfire than a mechanical bump... with a very sharp crack (not all that loud most of the time though). But I can't think of what would cause backfire on after re-applying throttle after letting it completely off. My TPS is set dead-on and has no dead spots... Unless it's possible for the diff to make a sound VERY much like a backfire?

I took my car to get a car wash and the pressure sensor light issue seemed to go away for about a minute...then it came back on again. wierd...

The idle is pretty damn solid though. It isn't rock-solid but it's reasonably good.

But I still want to know why I can't get it to adjust any higher... despite the the fact that the BAC isn't working.



Oh yeah, wouldn't it be possible to block off the AVC entirely (seeing as how I don't have a split air pipe anyway, and everything else the AVC does is just causing problems) and just re-route the air pump's pressure to the VDI and 6PI systems? That way I could eliminate the AVC but not have to set up electric 6PI/VDI (although I guess just having a small, quiet electric pump running at maybe 5-6 PSI at all times hooked up to the stock solenoids would work fairly well... (...so I can just get rid of the damn air pump...although that would probably mean I need a double pulley)

I suck at wiring/electric things though :p (plus I'm a cheap bastard)

I guess I'd need the pump, and a relay to make it only run when the engine is running...

You know what would be awesome... a file that would let you print out the correct shapes of the gaskets onto gasket paper. That would be hell of a lot easier than tracing them from the parts.

Valkyrie

Well that's wierd...

I tried putting the pressure sensor in the freezer for a few hours to see if that had an effect on the resistances or something (it didn't)... and then I tried to get it hot by putting on my heater overnight, but all it did was get luke-warm by morning.

It was already fairly warm outside but the problem got even worse with the lukewarm sensor... after about an hour of highway driving the problem went away entirely. So I think the sensor only works right when it's hot, or perhaps just when the engine bay is hot/heatsoaked...

I guess I need to go ahead and get a used/new one to eliminate the most likely culprit.

Valkyrie

There was an exhaust leak where the downpipe connects to the manifold... guess I need a new gasket and some high-temp RTV to be on the safe side.

Also, the catalytic converter was blowing air out of it's pipe...is that normal if you don't have a split air pipe?

Valkyrie

God, replacing that gasket is a total PITA...

Also, the diff mounts seemed to be in working condition (both visually and from jacking the car up with the diff)

So I wonder what is causing the popping... in the case that it's afterburn?