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-   -   740: Why do I have a Saab valve on my car? And/or is this why I have no power under boost? (https://forums.turbobricks.com/showthread.php?t=279811)

AdmiralSenn 05-26-2013 07:47 PM

Why do I have a Saab valve on my car? And/or is this why I have no power under boost?
 
1991 740, B230FT, 16vT with Garrett T3. I did not build this car and I am fairly new to turbocharging, so please bear with me.

Lately my car has had some trouble with power. It drives almost exactly like a naturally aspirated 740. The compressor is spinning up, it's generating boost (currently at 10 psi) but there's only a teensy little bit of acceleration that dies off almost before you feel it. Prior to a few weeks ago it was just as quick as I could ask it to be.

After some searching and pondering, my first thought is that I have a boost leak somewhere so I put together a tester and hooked it up. The hoses hold pressure up to about 20 psi, and I couldn't find any leaks by sound or feel anywhere.

Unfortunately there was also a loud POP, which it turns out is from a Bosch valve, item # 0280142105. This seems to be a Saab overpressure valve, which seems to have taken the place of the external CBV that the T3 in the car came with. It was venting to atmosphere, so I guess it's sort of a BOV given the way it's plumbed.

In fact, the more I look at it the more I wonder if it was even hooked up to the correct port at all. The car has always had a strange noise off boost that sounded like really quiet compressor surge, but the previous owner said that it wasn't when I test drove it. This thing has some sort of vacuum diaphragm but pressure from that side wouldn't open up the valve at all as far as I can tell.

Is this a common modification? <strike>I don't remember ever seeing a reference to this being used on a Volvo before.</strike> It looks like I have an oddly numbered variant, I just found a bunch of threads describing very similar parts with final digits off by one or two. Can anyone who's used one of these tell/show me how it should be plumbed?

And since it apparently held pressure until today, what else should I be looking at to find my boost problem?

For now I guess I'll push the MBC down to zero pounds and drive it like I'm scared of it.

Thanks!

BrianB 05-27-2013 02:51 AM

This might clear things up a bit for you.

http://forums.turbobricks.com/showthread.php?t=231607

Some more:

http://forums.turbobricks.com/showthread.php?t=157725
http://forums.turbobricks.com/showthread.php?t=137666

AdmiralSenn 05-27-2013 03:12 PM

Okay, I am fairly sure my hoses aren't collapsing, as the car revs freely as high as I want, it just doesn't accelerate. And I don't have a torn intake coupler or hose, as far as I can tell. Accelerating slowly makes no difference.

Pretty sure my AMM is okay. I had some sketchy contacts on it, cleaned and tightened them. When the AMM was giving me trouble the car behaved completely differently, refusing to accelerate at all, bucking and generally being difficult.

From the pictures in those threads it looks like two of the three ports on the bypass valve were hooked up correctly, so dumping to atmosphere would just result in a rich spike on my car. I do remember occasionally smelling a little gasoline smell back when the car was running correctly, so it looks like that's my issue. I'm guessing that the surge-type noise I was hearing was the valve fluttering.

I'll have to make a junkyard run tomorrow and see if I can scrounge up a few replacements. Hopefully that's all this is.

AdmiralSenn 05-27-2013 03:13 PM

Okay, I am fairly sure my hoses aren't collapsing, as the car revs freely as high as I want, it just doesn't accelerate. And I don't have a torn intake coupler or hose, as far as I can tell. Accelerating slowly makes no difference.

Pretty sure my AMM is okay. I had some sketchy contacts on it, cleaned and tightened them. When the AMM was giving me trouble the car behaved completely differently, refusing to accelerate at all, bucking and generally being difficult.

From the pictures in those threads it looks like two of the three ports on the bypass valve were hooked up correctly, so dumping to atmosphere would just result in a rich spike on my car. I do remember occasionally smelling a little gasoline smell back when the car was running correctly, so it looks like that's my issue. I'm guessing that the surge-type noise I was hearing was the valve fluttering.

I'll have to make a junkyard run tomorrow and see if I can scrounge up a few replacements. Hopefully that's all this is.

Canuckvolvo 05-27-2013 04:09 PM

If it's a CBV venting to atmosphere, it will be open during cruising, sucking in unmetered air, unless the diaphragm pre-load is set high enough (if that model is adjustable).

Can you verify you are getting 10psi in the intake manifold, not pre-throttle body?

AdmiralSenn 05-29-2013 07:04 PM

Quote:

Originally Posted by Canuckvolvo (Post 4596656)
If it's a CBV venting to atmosphere, it will be open during cruising, sucking in unmetered air, unless the diaphragm pre-load is set high enough (if that model is adjustable).

Can you verify you are getting 10psi in the intake manifold, not pre-throttle body?

My boost/vac gauge is plumbed after the throttle body, into the same line that feeds the FPR on the rail. (I checked that the FPR is not leaking, just to be sure.) I assume that's what you mean?

That valve is not adjustable. If I had the money handy I would grab a Forge 007 but right now I'm limited to whatever I can find in the scrap yard or on ebay. Haven't had a chance to check the yard yet.

doucheNozzle 05-30-2013 06:49 PM

Was this a previous TB'ers car? Maybe some pictures of how things are setup. Sounds like you're on LH2.X?

lummert 05-30-2013 06:52 PM

Maybe for the same reason I have a Saab coolant cap on my car. Because it works for me.

AdmiralSenn 05-31-2013 06:54 PM

Quote:

Originally Posted by doucheNozzle (Post 4599662)
Was this a previous TB'ers car? Maybe some pictures of how things are setup. Sounds like you're on LH2.X?

Yeah, I know he was on here at least for a while because he originally listed the car for sale here a long ways back. I bought it from him directly since he's an old family friend.

It's LH2.4. Should have mentioned that before, sorry.

Here's the only picture I have handy besides a really blurry shot of the turbo ID tag. Anything in particular I should take a picture of that would help with diagnosis? http://i.imgur.com/HKrndvG.jpg

Hank Scorpio 06-01-2013 09:52 AM

Quote:

Originally Posted by AdmiralSenn (Post 4600652)
Yeah, I know he was on here at least for a while because he originally listed the car for sale here a long ways back. I bought it from him directly since he's an old family friend.

It's LH2.4. Should have mentioned that before, sorry.

Here's the only picture I have handy besides a really blurry shot of the turbo ID tag. Anything in particular I should take a picture of that would help with diagnosis? http://i.imgur.com/HKrndvG.jpg

That CBV needs to be plumbed back into the intake pre turbo.

Also that hose looks fairly kinked off, probably not helping.

Try this, pull the CBV and plug the port for now. Try accelerating and see if that improves (one thing, avoid suddenly snapping the throttle shut after being in boost as you'll have no pressure relief while its "bypassed".

AdmiralSenn 06-02-2013 02:38 AM

Quote:

Originally Posted by Hank Scorpio (Post 4601046)
That CBV needs to be plumbed back into the intake pre turbo.

Also that hose looks fairly kinked off, probably not helping.

Try this, pull the CBV and plug the port for now. Try accelerating and see if that improves (one thing, avoid suddenly snapping the throttle shut after being in boost as you'll have no pressure relief while its "bypassed".

Yeah, I'm going to look at some better plumbing stuff but I don't have any spare hoses to mess with so I'll have to do some measuring and order something online most likely.

I did get a replacement CBV of the same type, but the "better" model (ending in 110, supposedly built for ~10-15 pounds of boost rather than 7-10) that's supposed to be more durable. Haven't had a chance to run without it, but with the new one installed it definitely feels better. Instead of the faint surge I was hearing I get what you would expect from an open-port CBV, a nice BOV-like hiss on deceleration.

Not sure if the boost issue is fixed, as it rained tonight, so my drive was a little too scary to attempt any boost. It did seem like it pulled a little harder than it had been lately, but the tires started spinning before I could get any real sense of how it's performing, so I laid off for the night. I will drive it some tomorrow and see if the new CBV fixed the problem.

I do also have an issue with it not wanting to idle when cold and dying after letting off the gas after boost, which was a problem I had when I got the car that "fixed" itself. It seems that the CBV being open was helping it smooth out the idle, and now that I have the stronger model it's not open at idle any more. I am going to test the throttle switch and its alignment as I know it's been messed with at least once. The IAC does operate if I put the ECU in test mode, so I know that's working.


tl;dr: multiple issues now presenting symptoms, CBV was only part of it. Test drive inconclusive due to wet streets.

AdmiralSenn 06-22-2013 09:58 AM

After a few more weeks of driving it with some new parts, here's where I stand.

Replaced AMM with known good rebuilt unit. No change.
Replaced CBV with higher-quality, non exploded CBV. CBV now functions although it is still venting to atmosphere. It does not feel like there is any vacuum on it at idle.

Car pops on initial throttle tip-in whether in gear or in neutral. I'm not sure if it's a backfire or something else, it sounds like someone smacking the end of a hollow tube. Maybe an intake backfire?

Car hesitates after these pops, and eventually engages and drives normally (as a naturally aspirated 16V) after a second or two. If I really step on it it will occasionally do the same thing at higher RPMs under load, but that's only happened once or twice and I can't seem to duplicate it.

TPS is adjusted correctly and idle motor appears to engage as it should. Pinching off the idle hose to the manifold does not affect the motor, I am looking for post-throttle body leaks but haven't found anything.

Unplugging the AMM and plugging it back in results in about a 600 RPM increase in idle speed and almost complete reduction of the hesitation and popping. I am not sure if this is normal or what this does to LH2.4 - I know unplugging the AMM puts it in limp-home mode but I don't know what effect reattaching it does.

I think I found a major boost leak and will be testing that today, but I don't want to apply boost until I fix this other issue.

Thanks!

doucheNozzle 06-22-2013 10:26 AM

If your AMM is in the stock place, a boost leak means a vacuum leak which means you **** ain't going to run correctly.

tryingbe 06-22-2013 11:09 AM

Fix both the boost leak and vent to atmosphere.

AdmiralSenn 06-22-2013 05:58 PM

Well, I finally got some time to work on the car today. After spending about half an hour with the compressor hooked up to the turbo inlet hose and pushing 20-25 psi through the intake I was unable to find any boost leaks after all. The hose I suspected to be the problem is actually fine - it rubbed up against something and rubbed a small divot in the outer sheath, but it's not leaking. I will replace it soon but for now it's not the problem - I added a few layers of padded tape to keep it from rubbing any more. I did take all of the older looking hoses off and inspect them by flexing and twisting them but it turns out they're just faded, not cracked. Checked the throttle body, it's clean. Checked the FPR, it's not leaking.

I did end up pulling the fuse for the ECU to reset it and that seems to have fixed the stumbling problem. It now drives beautifully under any condition, no backfires, no hesitation. Idle is back to normal, throttle response is back to normal.

Still no power from the turbo though. Gauge reads 10 psi, dropping to around 8 after a second. I'm not even approaching high revs, the car runs completely out of steam before 6000 RPM. Previously I was getting some boost at around 3000.

I'm aware that the CBV venting to atmosphere is bad, but I did drive it like this for a few months straight with zero issues and it pulled as hard as I could have wanted. It's on the to-fix list but because of the way everything is plumbed I would pretty much have to redo the whole intake and the hot side of the intercooler, and I don't have the budget to blow on a ton of new hoses right now. If I move the AMM->Turbo hose forward to install a port for the CBV, it'll kink the hose pretty badly. It looks like everything is made from OEM Volvo hoses so I'm guessing I will eventually end up buying a bunch of hose lengths and bends from siliconeintakes.com to rebuild it.

Sorry for all the stupidity on my part, I'm trying to learn while diagnosing.

Bensin 06-23-2013 02:06 PM

Have you <del>considered </del> CERTAIN the hose from AMM to turbo isn't collapsing under boost?

The pressure test won't show this collapse because it makes hoses expand with pressure.

When actually driving the opposite effect is happening: the turbo literally is sucking air out of the AMM into the turbo and an old oil soaked hose will distort and make a smaller opening, choking the boost. A cheap fix is to take a second hose clamp (or two) and place it between the AMM and the crankcase inlet hose stub. this helps hose stay round instead of squished under the intensity of boost.

AdmiralSenn 06-23-2013 04:46 PM

Quote:

Originally Posted by Bensin (Post 4618590)
Have you <del>considered </del> CERTAIN the hose from AMM to turbo isn't collapsing under boost?

I was fairly certain, but I tried the extra clamp trick anyway.

It did make a difference, although I don't have the level of power I had before, there is definitely a bit of boost there. I'll try adding a few more clamps.

I'm assuming that if the hose collapsing is my major problem, then I should expect an occasional backfire under load and code 1-1-3?

Also, my intake hose is the one with the heater for the crankcase vent system. Is that necessary and/or is there a better way to handle that? I'm trying to figure out if I can build a replacement hose from silicone parts.

Bensin 06-24-2013 04:57 PM

Sounds like you have more than one problem. I don't have OBD on my 86 car, so I don't know codes. I don't know typical causes of backfire, but it makes me think ignition. Are your spark plug wires good? Distributor cap and rotor good?

Quote:

my intake hose is the one with the heater for the crankcase vent system.
?? Need some more clarification on this style, or even better, some photos.

By the way, the BOV is also stock for Volvo's with Garretts, it's just they way it's connected isn't standard.

AdmiralSenn 06-24-2013 05:38 PM

Quote:

Originally Posted by Bensin (Post 4619549)
Sounds like you have more than one problem. I don't have OBD on my 86 car, so I don't know codes. I don't know typical causes of backfire, but it makes me think ignition. Are your spark plug wires good? Distributor cap and rotor good?

?? Need some more clarification on this style, or even better, some photos.

By the way, the BOV is also stock for Volvo's with Garretts, it's just they way it's connected isn't standard.

http://www.ipdusa.com/products/7132/...ntake-hose-740

That's the hose I have. It's got a two-wire plug in it to heat the air going to the crankcase vent. I read somewhere that it was to help de-ice the system in cold weather, but I don't know if that's entirely true or if removing it would be a problem.

Spark plug wires are in good shape, cap and rotor looked good when I first drove the car a few months ago although I will check them again next time I get to work on the car. I actually busted the coil wire when I first got the car and replaced it with a brand new one I had as a spare for my other 740, so I know that one at least isn't the problem.

The intake hose is definitely creased in a way that will encourage it to collapse and seems to be getting worse, so I'm putting together a parts list to replace it with something more durable. The only holdups are figuring out the crankcase vent setup and actually having the money to put it together. If I can just ignore the heater in that tube I can just add another regular port and be done.

The power loss problem seems to be almost entirely absent from a cold start and gets progressively worse over a long drive, which I think is consistent with the hose collapsing as it gets warmer. I feel pretty stupid for ignoring the possibility before.

Bensin 06-24-2013 08:56 PM

I see, I have heard of this heater set-up but no experience with it. The only concern with it disconnected is what receives the signal? is disconnection going to change the ECU readings or LH system readings? I'm sure this has been covered on tbricks before (search google with "site:turbobricks.com [search words]")

Look up crankcase system or PCV. The hose simply starts at oil trap and runs to turbo hose; there is small y-joint of sorts that connects a small hose to manifold. But then the turbo may not be stock if the BOV vents into engine bay. I think maybe turbo is supposed to have the BOV built into it, which is usually called a CBV, compressor blow-off valve instead, does the same thing, different name.

Also try Google images for your engine, 16v is less common compared to 8v.

Don't worry about not knowing about hose collapse, turbocharging is a System, not simply a single part, by the end of this you likely know all about them!

AdmiralSenn 06-25-2013 07:43 PM

Quote:

Originally Posted by Bensin (Post 4619709)
I see, I have heard of this heater set-up but no experience with it. The only concern with it disconnected is what receives the signal? is disconnection going to change the ECU readings or LH system readings? I'm sure this has been covered on tbricks before (search google with "site:turbobricks.com [search words]")

I've been doing nothing BUT googling TB for answers. :lol: I have a fairly good grasp of how the PCV system is supposed to work. There doesn't seem to be any signal involved from the heater in this variant. I think this is something that was included on some cars destined for colder climates. Since I'm in Florida I don't *think* I'll hurt anything by leaving it off. Since most Volvos don't seem to need a heater there I think I'm safe.

The problem with figuring this out via pictures is that a lot of this car is 'customized' with mostly factory Volvo parts, so it has the wrong turbo with external CBV instead of internal, the wrong hoses, the Saab CBV instead of the OEM Pierburg, etc etc. But it all looks nearly stock. The work was done well, it just needs updating.

Hopefully I can get the new hose stuff ordered in the next few days and solve this problem. And hopefully the stupid hose is all it needs..

Lord_Athlon 06-25-2013 07:51 PM

A 91 didnt have a pierburg, nor did it have a t3.

poulrais 06-25-2013 08:02 PM

Have you checked your wastegate actuator?

AdmiralSenn 06-25-2013 08:19 PM

Quote:

Originally Posted by Lord_Athlon (Post 4620544)
A 91 didnt have a pierburg, nor did it have a t3.

Right, which is why I said it has the wrong turbo. I did uncover that tidbit in my reading.

Quote:

Originally Posted by poulrais (Post 4620553)
Have you checked your wastegate actuator?

No, but wouldn't that being stuck/broken result in it either overboosting or not building boost at all? The boost level on the gauge varies with the MBC setting appropriately, so I *think* that's okay. How would I check it, just apply air to the hose and see if I can see it moving?

poulrais 06-26-2013 07:36 AM

Quote:

Originally Posted by AdmiralSenn (Post 4620565)
Right, which is why I said it has the wrong turbo. I did uncover that tidbit in my reading.



No, but wouldn't that being stuck/broken result in it either overboosting or not building boost at all? The boost level on the gauge varies with the MBC setting appropriately, so I *think* that's okay. How would I check it, just apply air to the hose and see if I can see it moving?


Well I once had a similar problem on my 744 once and it turned out to be a disconnected wastegate actuator arm. It would build boost but the turbo was working very hard in order to do so. Do you hear a pretty loud hissing sound while on boost?

AdmiralSenn 07-10-2013 03:57 PM

Quote:

Originally Posted by poulrais (Post 4620931)
Well I once had a similar problem on my 744 once and it turned out to be a disconnected wastegate actuator arm. It would build boost but the turbo was working very hard in order to do so. Do you hear a pretty loud hissing sound while on boost?

I do hear a loud hissing, but I just checked and the wastegate actuator is closing and is not stuck open. I applied pressure from my air compressor and at about 7 psi it starts to open and moves without binding or sticking - even a quick pulse of air above 7 psi and it shoots closed. I cannot move it on my own, which I understand is correct operation.

So, here's where I'm at now. This keeps getting more and more confusing.

Symptoms:

1) Every second or third start the car will not idle until warm. Resetting the ECU via battery disconnect or fuse pull causes it to idle perfectly.

2) If the car is driven without resetting the ECU, occasional 'thoomp' sounds come from what sounds like the intake on light throttle application in neutral or on a hard acceleration above ~6000 RPM. No issues other than no boost in between those two extremes. Occasionally after one of these I will get a CEL and code 1-1-3 (incorrect mixture), but most of the time nothing.

3) Boost gauge registers pressure according to whatever I set the MBC to, but there is either no power from the turbo or very little.

Things I've done/checked:
Pre-turbo intake hose is now brand new silicone, no change in performance or symptoms.
Turbo to intercooler hose has no cracks. Intercooler to manifold hose is a solid pipe with a straight coupler on one end and an elbow at the throttle body, also no cracks in any of those.
If there are any leaks remaining in the system they are so slight that I cannot detect them.
Idle valve is working correctly.
TPS is adjusted correctly.
Throttle body is clean.
Wastegate is operating correctly.
Plugs are in good condition with a healthy tan color.

I'm leaning towards an electrical issue of some kind, maybe a sensor or ECU fault but I don't even know where else to look. That or I'm an idiot and somehow missed a huge leak, but I think I'm out of potential leaks to investigate. I just pressure tested it again and still can't hear or feel any leaks. Even a slight application of air from the compressor causes any flexible hoses to immediately inflate and there is no hissing except for the air whooshing past the turbo fins.

I am confused.

AdmiralSenn 07-19-2013 05:29 PM

Slight update.

In addition to the list in the last post, the MAF terminals and connector are now brand new, switching MAFs makes zero difference. Also I pulled the cat and it made no difference so it's back on the car. Exhaust is definitely not plugged or restricted.

The last few days, the popping has seemed to be less severe. Now if I hit boost, right when I should feel the power kick in the car acts like it was suddenly attached to an extra half-ton of weight - abrupt slowdown, bucking and fighting unless I ease off the gas. I smell gassy exhaust fairly frequently although the plugs aren't discolored and I can never track down the source, nor am I seeing black smoke or anything of that nature. FPR is not leaking.

I know this thread is all over the place guys, I'm sorry. The symptoms keep shifting and I obviously have more than one issue. Still no codes on fuel or ignition.

What else could this be? Blocked fuel filter? Bad O2 sensor? Bad ignition coil?

Lord_Athlon 07-19-2013 05:33 PM

Sounds like a boost leak honestly. Huge vac leak.

AdmiralSenn 07-19-2013 05:39 PM

Quote:

Originally Posted by Lord_Athlon (Post 4636370)
Sounds like a boost leak honestly. Huge vac leak.

I know it does, but I simply cannot find one. I am going to replace the rest of the intake hoses next week just in case, but seriously I can't imagine how I could have any leaks left or why I wouldn't be able to find them with a pressure test.

Plus, wouldn't a huge boost leak mean the vac/boost gauge wouldn't register full pressure?

At this point if I have a leak it's got to be something like a crack in the intake manifold or something.

It's really bizarre since if I keep out of boost the car drives beautifully, like a naturally aspirated 16V Volvo.

doucheNozzle 07-19-2013 05:40 PM

Do you have a compressor? You can make an air fitting.

AdmiralSenn 07-19-2013 05:42 PM

I have made a full pressure test rig complete with adjustable pressure nozzle, still can't find a leak. Went up to 22 psi and can't hear or feel anything but the sound of air whooshing past the turbo blades.

Lord_Athlon 07-19-2013 05:46 PM

Quote:

Originally Posted by AdmiralSenn (Post 4636372)
I know it does, but I simply cannot find one. I am going to replace the rest of the intake hoses next week just in case, but seriously I can't imagine how I could have any leaks left or why I wouldn't be able to find them with a pressure test.

Plus, wouldn't a huge boost leak mean the vac/boost gauge wouldn't register full pressure?

At this point if I have a leak it's got to be something like a crack in the intake manifold or something.

It's really bizarre since if I keep out of boost the car drives beautifully, like a naturally aspirated 16V Volvo.

No it wouldnt. There is a wastegate. Its purpose in simple terms is to maintain pressure in the intake. If the crappy hose coming off the turbo is leaking Xcfm equal to lets say 2-3psi, the wastegate would remain closed and the pressure would stay the same.

AdmiralSenn 07-21-2013 05:55 PM

Well, today I learned something. Thanks! That's the kind of 'duh' stuff I'm missing from just not being terribly well educated about how turbo cars work when taken as a system.

I did pull the compression side air hose off the turbo and check it again today. It's not in great shape but I still can't find any holes through it. A few cracks but none that penetrate through all the way or even much beyond the outer surface. There is a mushy spot near the exhaust manifold but it's still intact. I trimmed the cracked area off but it made no difference.

I'll see what happens when I replace that hose assembly - gotta wait for some income first. The car sounds like a weedwhacker at the moment. I really hope that's it, this is getting ridiculous.

AdmiralSenn 08-12-2013 07:41 PM

Rargh zombie thread.

First of all, I was wrong, you were all right, the CBV was sucking in unmetered air. I don't know how I didn't see it before, maybe it was stuck or something, but yeah that was definitely part of the issue. Pops and stumbling are gone as far as I can tell.

New piping installed, everything from the compressor to the intercooler inlet is new. Pressure test post intercooler holds pressure, pressure test pre compressor leaks down quickly and there is a loud whoosh, but it's not coming from the boost plumbing. The wastegate isn't moving unless I put the air system directly on the line heading to it.

The thing is I can't figure out where the air might be going. Pretty sure the wastegate actuator isn't leaking internally or it wouldn't work when air is applied to it, right?. The air outlet and inlet on the turbo are all brand new silicone and aluminum and it's all tightened down nicely using new T-bolt clamps finished off with a low-power hit from the impact electric wrench just to make sure. The air seems to be coming out near the wastegate actuator or at least on that side, but I'll have to go back to it tomorrow because the manifold was too hot for me to get in there and feel around.

Any ideas, guys? I really can't afford to just yank the turbo out and explore without a REALLY good reason.

Thanks!

Bensin 08-13-2013 06:32 PM

Stock BOV flow directions
 
Quote:

Originally Posted by AdmiralSenn (Post 4595910)
Unfortunately there was also a loud POP, which it turns out is from a Bosch valve, item # 0280142105. This seems to be a Saab overpressure valve, which seems to have taken the place of the external CBV that the T3 in the car came with. It was venting to atmosphere, so I guess it's sort of a BOV given the way it's plumbed.

In fact, the more I look at it the more I wonder if it was even hooked up to the correct port at all. The car has always had a strange noise off boost that sounded like really quiet compressor surge, but the previous owner said that it wasn't when I test drove it. This thing has some sort of vacuum diaphragm but pressure from that side wouldn't open up the valve at all as far as I can tell.

Is this a common modification? <strike>I don't remember ever seeing a reference to this being used on a Volvo before.</strike> It looks like I have an oddly numbered variant, I just found a bunch of threads describing very similar parts with final digits off by one or two. Can anyone who's used one of these tell/show me how it should be plumbed?

I'm looking back on your thread, did the BOV get figured out, as mentioned above? If the blow off valve isn't configured right, it certainly could be causing problems.

See this post: http://forums.turbobricks.com/showpo...7&postcount=38 Is this what you have?

Then this image shows how air flows through a stock system. However, the BOV is different than the Bosch. and NOT SHOWN: The vacuum hose running from manifold to BOV.

http://www.pbase.com/740atl/image/148629219.jpg

AdmiralSenn 08-13-2013 08:35 PM

I did get it figured out - it's actually a CBV that was routed as a BOV. As of a few days ago it is correctly installed and the bulk of my driveability and idle problems are gone - still no boost though. And yes, that first link is what I have. My issue was that the vent back into the intake was missing, causing a massive vacuum leak at low/no throttle - the signal line was working fine.

Tomorrow I will be getting the last piece of my new intake put on and then I can test it in earnest - I broke a connector and had to cobble together something using a PVC pipe fitting to make it match up, which has of course already started to deform. (Don't judge me, you can't get anything in this town!) My custom aluminum replacement should be done tomorrow.

So as of now it's basically running like a B234F.

AdmiralSenn 08-17-2013 05:48 PM

Okay, a few days driving around with the completed intake. I now get intermittent moments of boost, although it seems to depend a lot on how warm things are.

I have to put the car up to change the oil shortly and will be taking off the belly pan so I can inspect the turbo more closely. The last air leak I can hear is coming from inboard on the turbo, near the wastegate. I'm starting to think that something is cracked.

Any ideas on what to look for besides an obvious hole?

AdmiralSenn 09-23-2013 06:37 PM

Nope, this thread still isn't dead yet. Miraculously, the car isn't either.

I finally have some time to work on the stupid car again. I've been driving it around and it seems to have settled into a reliable, if slow and boring, mode of operation. Pathetic attempts at boost when cold, getting less punchy as it warms up. Otherwise runs rock solid.

After buying a few more pieces for my kit, I have conclusively determined that the leak is either in the turbo housing itself or the wastegate actuator. I am leaning towards the actuator but before I go buying parts I want to check that I'm not crazy.

(Just for reference, the way I determined this was by applying a pressure plug to the turbo outlet and pressurizing the intake as normal. Pressure will not build in this configuration unless I hold the air compressor valve open. I did a similar test to rule out the intercooler with a perfect result - it held pressure north of 20 psi.) I can hear air leaking somewhere but I cannot feel air leaking anywhere.

Previously if I tested the wastegate actuator by applying air pressure directly to the signal hose, it would instantly move. However, if I pressurize the turbo from the air inlet, it doesn't start to move until around 30-40 psi! This strikes me as being a big problem. If I happen to be wrong here please let me know, but I think I'm finally on to something given that it's supposed to open at 7-8 psi stock.

If it ever stops raining (not going to risk my life on jackstands on a sloped, wet driveway), I am going to pull the actuator out, check the wastegate arm for smooth operation, and check for a blown gasket. Assuming I find a smoking gun in there, any recommendations for a Garrett T3 wastegate actuator? I don't mind spending a bit extra for something I can use for years. Current plans are to keep the car at ~12 psi until I can swap the M46 for something less likely to explode, so something adjustable would be nice but not necessary right away. I keep seeing references to a Forge unit but their website doesn't have one specifically for the T3, so it's probably a crossover and I have no idea which variant would be the right one - advice would be awesome!

Thanks again guys. With any luck I can FINALLY put this stupid project to rest and focus on something more fun.

AdmiralSenn 09-27-2013 08:29 PM

Help! Wastegate actuator
 
Okay, I ordered an ipd wastegate actuator and it's here and I'm trying to install it. The rod is a lot longer than the one that was on the car. Like, 1.5 - 2 inches longer.

Barring the rod difference, they look exactly the same. I believe the old one is the original T3 actuator. The old rod was not cut, it still has the original machined end.

Am I going to run into trouble here? It looks like it's enough of a difference that the wastegate will be stuck fully open at all times. But I don't want to be stupid and trim down the rod and end up in a runaway boost situation either.

Anyone run into anything like this before?

(By the way the old one was definitely leaking internally, although I don't yet know if this will fix the problem or not.)

AdmiralSenn 10-01-2013 12:01 AM

(Is anyone even still reading this? I know I'm rambling all over the place here.)

Ended up trimming the female-threaded portion of the actuator rod to fit, seems to work okay. I have no idea why they are different, the ipd one matches the ones I've seen in pictures for a T3. Once again my car is just weird. I'm wondering if maybe the previous owner threw a misfit Saab actuator on there at some point or something.

The new actuator was either the last air leak or at least the last major one, although I believe I have just traded an air quantity/pressure problem for a combustion problem since I'm not back to 100% operation yet.

When cold, the car will almost always take off like a rocket, just like when I first got it or near enough as makes no difference. As it warms up, it gets less punchy, until when it's fully warmed up it does something really odd.

Basically if I stomp on it, it will rev, build boost, nothing will happen, then I will get a backfire/pop (same noise as before, hollow sounding, more of a 'FOOMP' than anything else) accompanied by a fluttery/surgy noise, then at the upper end of the powerband it will suddenly catch and start moving, but by that point I've already let off the gas due to fear of damage. (I have stopped hitting the pedal hard because I believe I will cause some pricey, exciting damage if I keep trying it that way). It's actually kind of similar to the sensation of a turbo hose popped loose, only self-correcting.

If I had to describe it to a non-Volvo person I would say that it almost feels like it's building pressure against an obstruction, then blowing the obstruction loose at around 4-5000 RPM and resuming normal operation. I know that doesn't make much sense but that's the best way I can describe it.

If I feather the throttle carefully, it will accelerate fine, and sometimes even get a little bit of boost.

At this point I'm thinking I just need to start doing the rest of the stage 0 stuff, plugs/wires/cap/rotor, fuel filter, and see if that helps. RPM sensor is new, AMM is supposedly from a known good car although I may pick up a few more to see what happens.

Anyone have any 'check this first' stuff? My budget at the moment is less fantastic than usual, so I can't really afford to shotgun replace parts at this point.

AdmiralSenn 10-11-2013 05:54 PM

Update, fuel filter and plugs replaced.

Old fuel filter dripped brownish gas out, which left a nice debris residue after it evaporated. "Well, there's your problem..." Immediately the car ran smoother, but still no power.

Checked the plugs, and DANG my plugs got nasty FAST. In July I checked them and they seemed fine, the other day I decided to replace them just for kicks and giggles and three of them showed the charcoal-ish buildup of really nasty fuel deposits and such. Replaced with NGK BPR6ES @ .030" and the bulk of my problems seems to have gone away. I now have boost most of the time even when hot, although about half of the time it will still act like I have a huge boost leak. It seems to be getting better over time, and I'm guessing that the clean fuel is slowly cleaning the injectors out.

I will most likely eventually replace the injectors if I find a good new or rebuilt set of brown tops or equivalent that I can afford. May toss in some concentrated injector cleaner or something and see what happens.

Thanks for all the help, guys. I think I can call this issue closed and I am now moving on to the next problem, which is a big backlog of cosmetic issues and a state of general disassembly I need to address.

Yay for boost!

doucheNozzle 10-13-2013 09:39 PM

Boost!

AdmiralSenn 10-13-2013 09:55 PM

Indeed! I am quite pleased. I've even had a few runs where it approached or met the original performance when I bought the car. I think I'm going to dial the wastegate back in a turn or two and use the MBC to adjust boost from here on out though.

Bensin 10-14-2013 01:31 PM

Only sparkplugs - that's cool!

AdmiralSenn 10-14-2013 04:47 PM

Well, spark plugs, fuel filter, wastegate actuator, boost pipes and intake hose, and a poorly plumbed external CBV. Everything contributed and although it's still not 100%, it's getting there.

Now I just need to figure out why there's such a dramatic difference between when it's hot and when it's cold.

doucheNozzle 10-15-2013 02:05 PM

Quote:

Originally Posted by AdmiralSenn (Post 4713738)
Well, spark plugs, fuel filter, wastegate actuator, boost pipes and intake hose, and a poorly plumbed external CBV. Everything contributed and although it's still not 100%, it's getting there.

Now I just need to figure out why there's such a dramatic difference between when it's hot and when it's cold.

CTS could be bad.

Janspeed 10-15-2013 06:05 PM

that could also cause plug fouling. if coolant temp sensor is broken it may be getting over-rich mixture.

about the WGA: it should have some preload (like half the pin visible through the rod hole while the rod is detached)
dail in the desired boostlevel by using the boostcontroler. You should start to feel the boost from about 2200 on up. From 3000 on up the car should be hauling ass.

as for boostleaks: make sure the manifold has no leaking exhaust gaskets. And the turbo should be tightened down to avoid leaks between manifold and turbine. The compressor housing has a rubber seal or gasket between backingplate and snailhousing. If that leaks you also lose boost.
It's all in the details.

AdmiralSenn 10-15-2013 08:08 PM

I'll check the resistance on the CT sensor this week and see what happens. I do have a fancy Volvo OEM replacement on the shelf just in case, but I don't have an intake manifold gasket handy, will have to acquire one before I try to replace it.

Wastegate actuator is defintiely slightly too preloaded, this is on my list of things to deal with. I picked up an extra 3 pounds of boost. Just haven't had enough time between drives for the motor to cool off, and this weekend I was fighting a sinus thing and didn't even leave the house. When it picks up power it's pretty early, when it gets hot and stops boosting I don't feel the initial power onset until ~3500-4000.

Fairly sure the exhaust side isn't leaking, I haven't seen or heard any symptoms of an exhaust leak. I will check the turbo mounting studs on the manifold though.

I will have to do another intake leak test and make sure there isn't any air going anywhere it shouldn't. If there is one it's likely going to be in the turbo itself, probably the seal you describe. If that's the case I'll just have to live with the reduced performance until I can afford a replacement - I'm not going to risk the downtime on the car to rebuild the turbo if I can swap in a known good replacement and get more power out of it at the same time. Not sure what my options are for a water cooled T3 or T3/T4 that I could ever afford, though.

I'll update when I find something.

doucheNozzle 10-16-2013 10:10 AM

Do you have EGR on the car?

AdmiralSenn 10-16-2013 09:03 PM

Nope, no EGR.


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