I'm shocked, do I have compressor surge turbo damage?

[Falcon55]

Wazzup peeps? My first post here, this must be the best DSM enthusiast forum on the internet in my opinion, the rest are fakes. Back on topic, I hope it's not what I think it is, one of my greatest fears. Sorry for the long story.

Me and a friend (well friend of my friend), were trying to find out why my 97 GST would "buck" at around 5,000 RPM and why it would sometimes shut off while driving, after dropping down to 1,000 RPM idle (I knew how to fix that). Since the beginning, my older bro always told me it was the speed sensor causing the "buck" since the speedometer would "shift" around irregularly when driving. He's very wise about cars and I ignored him, big mistake.

So one night, me and my friend researched on DSMTuners, concluded that the bucking was probably a boost leak (maybe even spark plugs) and decided the next morning we have to work on the car. Next day, we go to the dealership, buy the gasket covers for the throttle body and install them. The shut off would still happen, but not often. Almost fixed. Afterwards, we work on the car again. He convinced me that I had a boost leak coming from my BOV when idle. We felt small gusts of air coming from the BOV with our palms. So he started to tighten the BOV until he thought the "leak" ceased. Now that I think of it, it's the stupidest thing I let someone do to to my car. I test drove the car and heard fluttering noises at low RPMs (below 3,000). At high RPMs, the usual spurting sound of excess air from the BOV would be heard. I didn't know what the flutter was, but recently I found out it's a term called compressor surge.

Believe it or not tho, the shut off idle problem has ceased afterwards, , I have no clue why.

Well to make a long story short, I drove it with the BOV tightened since Friday, Feb. 22 until March 2nd, Sunday. 9 days, but since I haven't drove my car 2 days of the 9 days, so far were looking at my car running with compressor surge for about 7 days give or take. That sunday night (mar. 2), outside with highschool friends (c/o 06 REPRESENT! ), my older bro noticed my car not sounding right. We popped the hood, first thing my bro noticed was the BOV. He yelled "WHAT THE F***? WHO DID THAT!?" I told him as he loosened up the BOV. He said again "It's the speed sensor that causes buck, not the BOV! Never let that friend touch your car, it may have ****ed up the turbo." I'm then shocked, so afterwards I unplug the speed sensor, test drive and guess what?

My older bro was right, it wasn't bucking, I could it take to any RPM while driving. He knew the speedometer would "Balloon" all the way to around 130MPH, hit the governer and cause the buck, while in reality I'm pushing the car hard at 30MPH. Why? Loose speed sensor that needed to be plugged in harder, easy fix.

So now i'm worried as hell since my turbo sounds just a bit wierd (not too noticable), also I don't know if it's me or if my GST isn't pulling like it used to. Not to mention that I now hear a slight "clacking" noise at about 2.5 RPM (stationary) from inside my intake manifold (cylinder above engine), IDK why. Wierdest thing is my car doesn't shut off anymore... My fear, I just hope that a week of driving with compressor surge didn't mess up my turbo. HELP! Greatly appreciated, anything would help!

As for myself, I lurked these forums sometimes before registering, but I finally decided to make an account.

 

[kenamond]

It looks like you could actually recirculate that bov. Loosen that clamp at the bottom and rotate it. Then go buy a new recirc tube and you should be good on the recirc end.

If he can figure out how to properly set up the BOV, yes. But he had surge problems with it. If anyone knows more about that BOV, chime in and give him some instruction on how to properly adjust it...or atleast identify it. It does look almost exactly like the one in the image he posted earlier ($250!!).

EDIT: This is from the site selling AVO BOVs (looks just like his): "AVO blow off valves are a 50/50 vent system that retains the return tube, keeping the stock computer system happy, while an additional vent sends hot air to atmosphere." That tells me that even if he hooks up the recirc tube, it'll still vent half the air.

 

[Black99gst]

just losen the bolt on the top almost all the way(losten the nut, then get a hex driver and losen it untill you can turn it by hand, then tighten it back up a full turn or two, then tighten back down the nut) if you are that worried about "compressor surge" i still however believe your problem is simply BOV flutter... which basically is happening because their isnt enough vac to open the BOV all the way, and their isnt enough air pressure (boost) to push the BOV open... so it "hops" open and closed...

 

[kenamond]

just losen the bolt on the top almost all the way(losten the nut, then get a hex driver and losen it untill you can turn it by hand, then tighten it back up a full turn or two, then tighten back down the nut) if you are that worried about "compressor surge" i still however believe your problem is simply BOV flutter... which basically is happening because their isnt enough vac to open the BOV all the way, and their isnt enough air pressure (boost) to push the BOV open... so it "hops" open and closed...

Any ideas about how to recirculate that BOV (all the air)?

 

[No_Skillz]

Any ideas about how to recirculate that BOV (all the air)?

No ideas if it truely is a 50/50 like you suspect. But I'm willing to let my stock 2g BOV go at shipping price to help a brother out. Send me a PM if you're interested. It's about time I cleared out some of my stock parts. Just to clarify, it's a stock 2G plastic BOV that worked fine the last time I had it on my car (about 1 year ago).

As kenamod suggested, get that boost leak done. In your last picture (post #23) it looks like you have a tear in your UICP. Might be a leak, might not. Be careful.

Are you also sure that your recirculation fitting on your intake snorkel is capped off? It'd be sort of a big deal if it wasn't...

Also, just to make sure, you're running 11psi with your MBC set almost all the way out, correct?

(Damn, that's where the stock coolant overflow bottle goes? I'd almost forgotten. )

 

[Falcon55]

Don't worry peeps, my intake snorkel is capped off. That was one of the first things I noticed when I bought my car, it looks like it was done by a professional. I'll show a pic if yall need to.

No ideas if it truely is a 50/50 like you suspect. But I'm willing to let my stock 2g BOV go at shipping price to help a brother out. Send me a PM if you're interested. It's about time I cleared out some of my stock parts. Just to clarify, it's a stock 2G plastic BOV that worked fine the last time I had it on my car (about 1 year ago).

As kenamod suggested, get that boost leak done. In your last picture (post #23) it looks like you have a tear in your UICP. Might be a leak, might not. Be careful.

Are you also sure that your recirculation fitting on your intake snorkel is capped off? It'd be sort of a big deal if it wasn't...

Also, just to make sure, you're running 11psi with your MBC set almost all the way out, correct?

(Damn, that's where the stock coolant overflow bottle goes? I'd almost forgotten. )

Really? I hear that, I appreciate your help. I'll PM you, i'm interested. You have pics of the 2G BOV? Also, I always noticed I had a tear on my UICP (I have no clue what that stands for, but I know what part it is). I doubt it's leaking, but ya never know, I'll check up on that soon. Like I said above, intake is capped off. MBC? What's that? Manual Boost Control? I don't have a boost controller, or at least not that I know of...?

Oil will get into the intake from the rubber hose that goes from the passenger side of the valve cover to the side of the intake pipe. Many folks will put a catchcan or in-line fuel filter on that hose to keep oil out of the intake pipe. That oil gets all over the inside of the intake tract and into the combustion chamber. Oil in the intercooler decreases its efficiency, and oil in the combustion chamber leaves deposits.

It's odd that you have no side-side shaft play but a small amount of in-out. I'd check on the shaft play every now and then to see if it gets worse.

Get a different BOV and recirculate it. Easiest and cheapest would be a 2g BOV and stock recirc tube. I imagine the intake pipe has a cap on the tube that would normally connect to the BOV? If not, it better; don't drive the car unless it's capped. Again, I'm talking about the tube on the part that you unclamped from the turbo to check shaft play.

Oh man, that's good to hear that it's nothing too serious about the oil. Although, it's not good either. My older bro told me he has a catchcan on the hose in his 240SX (SR20DET). I'll keep that in mind and do so aswell with my hose. Also, my older bro said to not worry about the very very minimal in-out play, he said that should be normal with most turbos as long as it wasn't too much play. I may still check on the turbo shaft play every month or so, just a precautionary method to make sure. The intake is capped, don't worry, I understood what you meant the first time around.

 

[No_Skillz]

The BOV is the stock plastic piece, and that's simply just what it's made of. All stock 2G bovs are plastic. I just wanted to make sure you know what you would be getting. 1G bov's were made of metal, so are higher quality and can hold more boost. If you plan on doing any mods at all, you honestly shouldn't waste time on mine; go for a 1g (maybe 10-20 bucks more) or a decent aftermarket one. If you're really that strapped for cash or don't plan on modding, PM me again, we'll work something out. I'll try to get pictures but might take me a week since my parts bin is at my mother's house.

UICP stands for Upper Inter-Cooler Pipe. In the stock sense, it's more of a large hose. Do a search for how to properly conduct a boost leak test. It will make your car run alot better.

MBC is manual boost controller. I got confused and thought you had one when you talked about Teeing into your actuator line. In the meantime, the BCS (boost control solenoid) watches how much boost your turbo is putting out.

From looking at your BOV, I'm a little concerned that the hose is hooked up to a pressure source. I might be wrong, but it looks like that nipple would be above the actual valve, so pressure wouldn't be appropriate. Instead, that line should be hooked up to someplace after the throttle body so it will pull vacuum when you're off the throttle. Anyone else have any thoughts on this?

 

[dsmconvict]

Take another pic of both sides of the bov. If it is 50/50 then get a new one if not just play around and adjust the one you have. No sense in buying something you don't need.

 

[kenamond]

MBC? What's that? Manual Boost Control? I don't have a boost controller, or at least not that I know of...?

You have a boost controller, but it's probably stock. It connects to the turbo compressor outlet, the wastegate actuator (bolted to the compressor housing, kind of brass-colored), the actual BCS (boost control solenoid) and the bottom of the intake pipe. It should keep your boost at about 10-12psi, so it sounds like it's working.

Oh man, that's good to hear that it's nothing too serious about the oil. Although, it's not good either. My older bro told me he has a catchcan on the hose in his 240SX (SR20DET). I'll keep that in mind and do so aswell with my hose.

If you do decide on a catch can for the VC breather line (the one dumping oil into your intake), it must be sealed with one inlet and one outlet. It can't suck air into the can other than from the inlet/outlet. One goes to the VC breather nipple, and the other goes to the intake pipe. If there is a vent or anything other than the in/out, you could have idle issues.

Also, my older bro said to not worry about the very very minimal in-out play, he said that should be normal with most turbos as long as it wasn't too much play. I may still check on the turbo shaft play every month or so, just a precautionary method to make sure.

You don't want *any* in/out play, but side/side is normal as long as it's not too much. A bit of in/out play tells me the turbo is worth monitoring occasionally. If it gets worse, you'll need to start thinking about rebuilding it or upgrading it. If you let it go until something fails, it just adds more work when you replace it. Rebuilding it is cheaper than a replacement, but most folks upgrade when the stock T25 is shot; it's a pretty small turbo and can't be pushed a whole lot farther, powerwise.

 

[Falcon55]

The BOV is the stock plastic piece, and that's simply just what it's made of. All stock 2G bovs are plastic. I just wanted to make sure you know what you would be getting. 1G bov's were made of metal, so are higher quality and can hold more boost. If you plan on doing any mods at all, you honestly shouldn't waste time on mine; go for a 1g (maybe 10-20 bucks more) or a decent aftermarket one. If you're really that strapped for cash or don't plan on modding, PM me again, we'll work something out. I'll try to get pictures but might take me a week since my parts bin is at my mother's house.

UICP stands for Upper Inter-Cooler Pipe. In the stock sense, it's more of a large hose. Do a search for how to properly conduct a boost leak test. It will make your car run alot better.

MBC is manual boost controller. I got confused and thought you had one when you talked about Teeing into your actuator line. In the meantime, the BCS (boost control solenoid) watches how much boost your turbo is putting out.

From looking at your BOV, I'm a little concerned that the hose is hooked up to a pressure source. I might be wrong, but it looks like that nipple would be above the actual valve, so pressure wouldn't be appropriate. Instead, that line should be hooked up to someplace after the throttle body so it will pull vacuum when you're off the throttle. Anyone else have any thoughts on this?

Ah ok, cool. Right now i'm just looking forward to getting my car running before anything, then I will start hooking it up. I always knew what the boost control solenoid was, don't worry. I have more pics to come in this post, let's see if the line is hooked up appropriately.

This is with the stock intake put back on, how my car would normally look:

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Take another pic of both sides of the bov. If it is 50/50 then get a new one if not just play around and adjust the one you have. No sense in buying something you don't need.

Here goes the pics u needed:

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You don't want *any* in/out play, but side/side is normal as long as it's not too much. A bit of in/out play tells me the turbo is worth monitoring occasionally. If it gets worse, you'll need to start thinking about rebuilding it or upgrading it. If you let it go until something fails, it just adds more work when you replace it. Rebuilding it is cheaper than a replacement, but most folks upgrade when the stock T25 is shot; it's a pretty small turbo and can't be pushed a whole lot farther, powerwise.

Well, my older bro has a spare T25 turbo (very low mileage, great working condition) he was showing me, which came from his 240SX. We checked up on it, it had minor side to side play like you mentioned and no in/out play what so ever. So I quickly took off my intake, then my older bro checked out the turbo on my GST. He said before he ever even checked it, he thought the way I was describing it was minimal micrometric (non noticeable) in/out play, but instead he would consider it "little" in/out play after checking it out. Instead of how I said "very very little" before, it's actually a little bit of play. So he concluded that I should definitely monitor my turbo, because it for sure has a bit of noticeable in/out play.

Another thing, like I said on my first post, I hear a little clacking noise coming from my intake manifold, even when idle while reving at around 2,500 RPM. It's coming from over here:

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Any ideas why? I also hear a constant click-click-click noise whenever I hold down my clutch, but I already know that's from the thrust bearing, it needs to be replaced.

Sorry if some of the pics are a lil way too bright, that sun down here in Miami is shining hard as hell:

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Oh, also notice my older bro's 300ZX right behind my car.

 

[kenamond]

From what I can tell, the BOV vaccuum line is on the correct things (one end on the intake manifold, one end on the BOV nipple), but you still need another BOV that you can recirculate.

You say that that BOV came with a 3000GT clip. What was on your car before that BOV in the picture?

Is the ticking you hear at the manifold just the injectors opening and closing? They click as the solenoid opens and closes. Also, it could be lifter tick.

A ticking thrust bearing doesn't sound good. The 2g 7-bolt motors have been known to crankwalk. If yours is walking, that's not good; replacing the bearing will buy you time, but won't stop it from happening again. But that's if it's crankwalk.

 

[PieEyedPiper]

Ah ok, cool. Right now i'm just looking forward to getting my car running before anything, then I will start hooking it up. I always knew what the boost control solenoid was, don't worry. I have more pics to come in this post, let's see if the line is hooked up appropriately.

This is with the stock intake put back on, how my car would normally look:

Here goes the pics u needed:


Well, my older bro has a spare T25 turbo (very low mileage, great working condition) he was showing me, which came from his 240SX. We checked up on it, it had minor side to side play like you mentioned and no in/out play what so ever. So I quickly took off my intake, then my older bro checked out the turbo on my GST. He said before he ever even checked it, he thought the way I was describing it was minimal micrometric (non noticeable) in/out play, but instead he would consider it "little" in/out play after checking it out. Instead of how I said "very very little" before, it's actually a little bit of play. So he concluded that I should definitely monitor my turbo, because it for sure has a bit of noticeable in/out play.

Another thing, like I said on my first post, I hear a little clacking noise coming from my intake manifold, even when idle while reving at around 2,500 RPM. It's coming from over here:


Any ideas why? I also hear a constant click-click-click noise whenever I hold down my clutch, but I already know that's from the thrust bearing, it needs to be replaced.

Sorry if some of the pics are a lil way too bright, that sun down here in Miami is shining hard as hell:





Oh, also notice my older bro's 300ZX right behind my car.

Go ahead and connect that tube to the opening on the BOV, as mentioned you just need to loosen the worm clamp and rotate the BOV so the outlet will match up with the recirc. tube.

Clicks with the clutch in, eh? Hate to say the C-word. Are you sure you want to try replacing the thrust vs. an engine swap?

The clicking you're hearing is most likely your lifters, aka, lash adjusters. Completely normal, yet still undesireable. You can remove and clean them, try running a little Seafoam in your crank case before an oil change, or even replace them with revised lifters that don't have such a large tendency to make noise.

 

[kenamond]

Go ahead and connect that tube to the opening on the BOV, as mentioned you just need to loosen the worm clamp and rotate the BOV so the outlet will match up with the recirc. tube.

That BOV is a 50/50 recirc BOV. See the oval hole in the opposite side? I assume that's where 50% of the air is vented. He might be able to rig something to block that off, but I'd just get a 2g BOV for now and call it a day...$15 tops.

Clicks with the clutch in, eh? Hate to say the C-word. Are you sure you want to try replacing the thrust vs. an engine swap?

Heh. That would kinda suck, but I agree. I'd swap in a 6-bolt rather than fix a walking 7-bolt.

 

[Black99gst]

That BOV is a 50/50 recirc BOV. See the oval hole in the opposite side? I assume that's where 50% of the air is vented. He might be able to rig something to block that off, but I'd just get a 2g BOV for now and call it a day...$15 tops.

+1... sorry man, you may be able to rig up something, and thats what i would try to do... the 2g oem bov in my opinion is junk....

also, just to clean the C/W issue, go into a parking lot, and drive in circles turning as tight as you can to the left, put the clutch in to the floor and stop, then continuing left in circles, let the clutch out as if you where going straight, if all is well, it will be, if the clutch wont come off the floor... we got bigger issues then a simple BOV vent...

 

[Falcon55]

First and foremost, before anything, I need to fix something I said:

Ah ok, cool. Right now i'm just looking forward to getting my car running before anything, then I will start hooking it up.

Sorry if any of you misunderstood, I meant to say "getting my car running right". I'm going to edit that above right now.

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You say that that BOV came with a 3000GT clip. What was on your car before that BOV in the picture?

Is the ticking you hear at the manifold just the injectors opening and closing? They click as the solenoid opens and closes. Also, it could be lifter tick.

A ticking thrust bearing doesn't sound good. The 2g 7-bolt motors have been known to crankwalk. If yours is walking, that's not good; replacing the bearing will buy you time, but won't stop it from happening again. But that's if it's crankwalk.

The thing is I didn't own the car before it had the BOV, I would assume it had stock recirculation. (am I correct?) I bought the car from a young friend (around same age as me) my older bro knew, now he's a mad cool friend of mine too. The car was supposed to be sold for $3,500, but he cut me some slack and let me have it for $3,100. By the way, CRANKWALK? No way, I don't really understand what that means, but from lurking on these forums before and hearing peeps talk about it in person, i'm pretty sure it's something really bad and a pain in the ass to deal with.

Go ahead and connect that tube to the opening on the BOV, as mentioned you just need to loosen the worm clamp and rotate the BOV so the outlet will match up with the recirc. tube.

Clicks with the clutch in, eh? Hate to say the C-word. Are you sure you want to try replacing the thrust vs. an engine swap?

The clicking you're hearing is most likely your lifters, aka, lash adjusters. Completely normal, yet still undesireable. You can remove and clean them, try running a little Seafoam in your crank case before an oil change, or even replace them with revised lifters that don't have such a large tendency to make noise.

C-word? Crankwalk? Damn, yall are really going to start scaring me in a sec, .

+1... sorry man, you may be able to rig up something, and thats what i would try to do... the 2g oem bov in my opinion is junk....

also, just to clean the C/W issue, go into a parking lot, and drive in circles turning as tight as you can to the left, put the clutch in to the floor and stop, then continuing left in circles, let the clutch out as if you where going straight, if all is well, it will be, if the clutch wont come off the floor... we got bigger issues then a simple BOV vent...

What? So wait, turn the car all the way to the left (driving in circles), put the clutch pedal to the floor and come to a stop. Now what? Move the wheel back to normal (straight), then let off the clutch and start moving again? Correct? I think I can understand most of what your saying, but can you give me a lil more details and just be a lil more specific as to what to do? Sorry...

The parking lot area is no problem for me, I can do it right outside my house, I have a big enough parking lot, just take a look at it for yourself:

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[Black99gst]

negative, take a hard left, come to stop, put car in first, drive (turning HARD left) if the clutch acts normal, everything is DANDY! if it sticks to the floor, or you feel high/low spots in the peddle, get ready to deal with probable C/W...

sorry for the delayed respose!