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Discussion Starter · #1 ·
Yes I know there are many threads about TCV's and I did use search extensively. OK now with that disclaimer out of the way here's my latest headache (literally...I smacked my head on the fender well messing around with the TCV last night :facepalm: )

Installed IPD TCV on Friday. Its the new design with the plastic elbows that thread in. Got it all hooked up after fighting with the hoses to get them all onto the nipples. Started car up, and went to do the learning procedure as outlined in the instructions.

Make the first half-throttle pull and although I don't have a boost gauge, it sure felt like a huge boost spike. Tried it 2 more times but felt very inconsistent, almost violent surging. So I drove around calmly for a bit and went home. I have the Autotech (Elevate) stage 3 tune, and thought maybe I should relearn the TCV with the stock tune. So I went back to stock tune tried that. Well I went to drive it and basically get a little boost in 1st and 2nd, but then it falls on its face. Highway driving is painful because it simply won't build boost. I had to drive to NY SAturday mornig and didn't have a chance to swap the stock TCV back in. I could hear the turbo whistling away the whole time, but I'm getting passed by tractor trailers because I can't get over 60mph going uphill on the interstate!!:thumbdown:

I disconnected my battery and zip tied the terminals together for 30minutes last night to reset the ECU. Started it up, but still same symptoms. I've checked the lines to make sure I hooked them up properly and I have. If the hoses were not slid all the way onto the TCV nipples could that cause this problem? I can't get one of them to slide all the way to the bottom of the nipples. Anyone have any tricks for getting them on more easily?

No CELs either, except the one for my O2 sensor I haven't put a spacer in yet.

I know some people are gonig to say "go back to stock TCV" and that's fine, but I would really like to figure out what I did wrong because unless its a faulty valve I think its probably something I did. Sorry for the long post. Work is slow today.
 

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May be something worthy to take up with IPD? If its hooked up properly it should function like a normal solenoid such as factory.
 

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Your symptoms are the excact same as i had with a faulty stock TCV. Had a IPD unit that I fittet to a 850 R with boost spikes as result. Just changed out my TCV for a new stock unit and did the Forge CBV conversion at the same time. Car now hold boost and delivers consistent power through the range. BTW the old diaphrame was not torn or otherwise damaged. Think maybe the stock TCV was due a change.

I`d say go back to stock..
 

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go to stock or you got your hoses backward. I would switch the two that arent hooked to the wastegate and try again. it seems like its overboosting and then cutting back to save the motor. Had it happen to me one time. but then I went to stock and it was fine. The stocker TCV is more than capable of handling up to 16psi boost
 

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Discussion Starter · #5 ·
If the intake and turbo hoses aren't backwards, and I switch them to check, making them backwards, do I risk blowing anything up? I'm all for experimenting but not at the risk of exploding turbos! I figure i'll try that, and if still no joy, stocker it is (with Forge CBV while I'm under there). Thanks fellas.
 

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With AWD the CBV is very tough and wont give any hp gains or anything. If yours seems to be working fine I woulding dig into it unles you have a few hours and some hair to lose.

PS I missed that you have Stage 3. with the atage 3 your CBV will prob go soon. DUDE you NEED at gauge. if your tuned that much a 50 gauge is worth it and will show any issues if you ahve them.

with switching the turbo manifold and intake lines and being tuned you could way overshoot the boost, so be careful and dont WOT. again if you had a gauge this would be easy. youll know almost right away tho if the lines are wrong. itll be very touchy and powerful then just fall off. kind of what it seems you have now though thats why i rec. the switch.

when you reset do you pull the fuses and turn the key on for a bit. Ive heard alot of stuff about proper procedure but in my case the only thing that ever seems to really relearn the tcv is to pull ecm fuses and disc batt then try to start for 10 sec. leave for 15 min and put it all back together. maybe overkill but I know it works.

honestly in the end the stocker tcv is just easiest. lengthen the vacuum lines get it out above the intake pipe and itll last forever. in my case i spliced into the electrical connection to get it right up near the radiator resevior.
 

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Discussion Starter · #7 ·
mkd - agreed with pretty much everything you said. Ordering a boost gauge tonight, and decided to hold off on CBV until this weekend when I have plenty of time. I actually had 2 of the 3 bolts out 2 weeks ago but the third frustrated me so much I put it back together. I have a new idea for the 3rd bolt now...we'll see if it works.

So I checked my lines AGAIN. Actually took the stock TCV, held it against its mount and looked at where the lines routed...........For all the certainty I had about them being right, well, I'm now about 99% sure I had the turbo and intakes backwards. Swapped them, now have battery disconnected and terminals zip-tied together. Will go out in about 15minutes, put back together, and see what happens. I actually reverted back to the stock tune while I figure out how badly I screwed it up.

PS - You decide what route to take with the exhaust/cat yet?
 

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It happens, hopefully that takes care of it for ya :thumbup:
 

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mkd - agreed with pretty much everything you said. Ordering a boost gauge tonight, and decided to hold off on CBV until this weekend when I have plenty of time. I actually had 2 of the 3 bolts out 2 weeks ago but the third frustrated me so much I put it back together. I have a new idea for the 3rd bolt now...we'll see if it works.

So I checked my lines AGAIN. Actually took the stock TCV, held it against its mount and looked at where the lines routed...........For all the certainty I had about them being right, well, I'm now about 99% sure I had the turbo and intakes backwards. Swapped them, now have battery disconnected and terminals zip-tied together. Will go out in about 15minutes, put back together, and see what happens. I actually reverted back to the stock tune while I figure out how badly I screwed it up.

PS - You decide what route to take with the exhaust/cat yet?
that 3rd bolt is the worst. I used a swivel on my socket with one of the those tiny finger rachets. the swivel was able to wedge a bit and turn it like 1/16 at a time.

For cat and exhaust I bought a 70 magnaflow muffler and 200 cell high flow cat for 100 bux. ill weld in a 10 o2 bung and have the rest welded in the car at a 125 qoute local. should be nice. I didnt want to spend the doe on a full catback and downpipe. Would have been like 1300 bux. this was its under 300 and I ge tthe nice sound, faster spool and a little hp bump. the real hp comes with a tune not a 750 dollar catback. lol at least in my opinion.
 

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99% sure I had the turbo and intakes backwards.
So if you reversed the red and blue, your wastegate control would move in the wrong direction in response to boost. The harder the TCV tried to pressurize (open) the wastegate, the more it stayed closed. Boost was effectively uncontrolled.

Triple check them:
Red - Turbo pressure way underneath turbo pointing horizontally to right side
Blue - Vent line to turbo air intake pointing vertically upward
Yellow - wastegate control on silver cylinder.

The TCV basically controls whether pressure or no pressure goes to the wastegate cylinder. No pressure allows boost. Pressure above a few psi starts to reduce boost, by opening the wastegate.
 

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Excuse me if I'm wrong, but I thought that if the red and blue lines were reversed, it would still function. If the valve were to fail with them reversed, it would fail "closed" which wouldn't let the wastegate open. Yes, no?
 

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Discussion Starter · #12 ·
I triple checked them just because you gave an idiot-proof description for me.

All good now! I can be taught!! Thanks again guys. Once more Swedespeed saves the day. :beer:

So if you reversed the red and blue, your wastegate control would move in the wrong direction in response to boost. The harder the TCV tried to pressurize (open) the wastegate, the more it stayed closed. Boost was effectively uncontrolled.

Triple check them:
Red - Turbo pressure way underneath turbo pointing horizontally to right side
Blue - Vent line to turbo air intake pointing vertically upward
Yellow - wastegate control on silver cylinder.

The TCV basically controls whether pressure or no pressure goes to the wastegate cylinder. No pressure allows boost. Pressure above a few psi starts to reduce boost, by opening the wastegate.
 

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Excuse me if I'm wrong, but I thought that if the red and blue lines were reversed, it would still function. If the valve were to fail with them reversed, it would fail "closed" which wouldn't let the wastegate open. Yes, no?
Please define "TCV open" and "TCV closed". Also please define "fail" :)

TCV has two states: red venting to yellow, or blue venting to yellow. The ECU pulses the TCV to interpolate between the two. The TCV can theoretically fail in either state, but normally it vents blue to yellow, i.e. no pressure on the wastegate.

Wastegate is by default closed. If the yellow line falls off, the car will boost continuously. OTOH, if you hook up the red port to the yellow port (bypassing the TCV), the car will be boost-limited, meaning it will never rise over a couple of psi. You can use this property to test, or to get home in fact.

Time was, before electronic control, that the TCV was just a BCV - a controlled leak between the red and yellow ports. It would withhold pressure from the wastegate until boost was built. Then, to protect against overshoot a blowoff or CBV was critical to safety. And, you could tweak boost response by dialing in the leak or altering the rod.

Today, the TCV does it all and only under command from the ECU. The exact property of the TCV and length of the rod are relatively less important. But if the TCV fails closed, or the rod is too short, or due to misplumbing if boost pressure fails to reach the wastegate, then boost will shoot up and the ECU can only go into limp mode to protect the engine. OTOH if the TCV fails open, it's what we call "valet mode". :)
 

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I liked the good old days of manual boost controls :p lol

Does anyone know if Autotech does boost by gear tunes? Is one of the best features of having EBC or in our case the TCV. I'm sure ARD will if they don't.
 

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Discussion Starter · #15 ·
OK now you've peaked my curiousity. What exactly is meant by "boost by gears"?

Also - now that I have the TCV hooked up properly it works, but I feel like the upper-end boost is lacking. Some posts mention this will happen while the ECU relearns. On that topic has anyone noticed that the "relearn" procedures on IPD's site versus Phuzzy's are markedly different? One says half-boost for a while, the other suggests 3rd gear WOT pulls. I can't imagine the valves function much differently from each other, so I found that intriguing.

Back to work...
 

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The goal in re-learning is to stay just south of full boost. This can be difficult because the IPD and Phuzzy valves are tighter-closing and faster-acting than stock, so it's very easy to overshoot.

When overshoot occurs, the ECU pulls back, but it can only learn if it finds the limit. If all it finds is "too much" it can't be very sure what's "just right".

Alternatively, Just Drive It. Things will work out more or less the same. But don't go nuts, because overboost isn't a great thing for the engine.

One other thing to re-check is that the CBV is tight and the fitting goes to the manifold and hasn't popped off up there. The backpressure is important to keep the CBV closed under load, and if it's "off" then the valve will open early, robbing a bit of boost whether the ECU wants it or not. Since you did loosen 2 out of 3 bolts, you may want to check that you tightened 2 out of 3. :rolleyes:
 

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Discussion Starter · #17 ·
So it worked sorta for the first drive. But all week I've had weak boost and no pickup. It just whistles away never building boost. So I took it out, put the stock one back in, and all back to normal. So weird...I contacted IPD and will send the valve back to see if it was faulty.
 

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Anyone tested the Elevate one yet? It's reasonably priced and Dons R&D seems to be stepping up lately.
 

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Discussion Starter · #19 ·
Anyone tested the Elevate one yet? It's reasonably priced and Dons R&D seems to be stepping up lately.
I've become so proficient at swapping TCVs this week I just may...just for kicks.
 

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So it worked sorta for the first drive. But all week I've had weak boost and no pickup. It just whistles away never building boost. So I took it out, put the stock one back in, and all back to normal. So weird...I contacted IPD and will send the valve back to see if it was faulty.
How was the IPD valve labeled, did it have red/yellow/blue spots on all 3 ports? Which were which?

ALso, by "whistled" do you mean you could hear the turbo, or was it more of an air leak kind of sound?
 
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