No boost (turbo won't spool), low idle

[ben1984j]

To give a bit of background, I shimmed my wastegate recently, and found that I had overdone it a little. So I removed a shim from both actuator bolts and put it back together. The car seemed to start fine, but then when I went to drive it I discovered I have no boost. The car felt incredibly sluggish compared to normal, and as I held the gas pedal down I looked at the boost gauge and sure enough it was at dead zero. Also, the car idles at about 500 rpm and wants to die when I come to a stop after driving. I don't know if all this happening right after the wastegate shim is a coincidence or not, but here's what I've checked so far:

-Wastegate appears to be fully functional, although I initially suspected it was stuck all the way open because of my symptoms. The spring still has plenty of strength. I replaced the vac line going from the turbo to the actuator as it was slightly cracked at one end, but that didn't help. I know the actuator can be tested, per TSRM, but from what I can tell that's just to make sure the wastegate opens at the desired pressure, right?
-No vac leaks, accordion hose is in good shape.
-The turbo compressor wheel spins freely.
-No codes.
-IC piping visually inspected for leaks, will look at in more detail tonight.

I though it would have to be a pre-turbo leak of some kind, since there seems to be no exhaust gas to spool up the turbo - is this correct? Any input or suggestions of any kind would be much appreciated. Thanks for your time.

-Ben

 

[thevork]

A boost leak between the turbo and your throttle body can also cause similar symptoms.

Even if your turbo is spinning and boosting like a madman, when you have a serious boost leak all your pressure will go out the door before reaching your TB. You will have no boost and run pig rich, which will let your car run like a snail.

A vacuum leak can also explain the bad idle/stalling.

Check the whole intake routing. Especially the hose coming from the turbo going to your IC.

BTW did you check for codes yet?

 

[ben1984j]

A boost leak between the turbo and your throttle body can also cause similar symptoms.

Even if your turbo is spinning and boosting like a madman, when you have a serious boost leak all your pressure will go out the door before reaching your TB. You will have no boost and run pig rich, which will let your car run like a snail.

A vacuum leak can also explain the bad idle/stalling.

Check the whole intake routing. Especially the hose coming from the turbo going to your IC.

BTW did you check for codes yet?

-No codes.

Yes I did check for codes

And I get what you're saying about a boost leak, but the thing is the turbo isn't "boosting and spooling like a madman." I'm listening and it definitely isn't spooling at all. I will re-check the IC piping again, but it would take a pretty substantial hole or something to cause my problem right? I'm leaning towards the wastegate again (as in, it's opening prematurely), but everyone else who's had that problem could still make some boost...

 

[bglover84]

Yes I did check for codes

And I get what you're saying about a boost leak, but the thing is the turbo isn't "boosting and spooling like a madman." I'm listening and it definitely isn't spooling at all. I will re-check the IC piping again, but it would take a pretty substantial hole or something to cause my problem right? I'm leaning towards the wastegate again (as in, it's opening prematurely), but everyone else who's had that problem could still make some boost...

Any resolution to your problem? I just rebuilt my engine and my stock boost gauge isn't working. My turbo is spooling but I wonder if it has anything to do with me shimming my wastegate. Don't have any engine codes either.

 

[carter]

kinda sounds like the shit mines doin lol, take a video

 

[bglover84]

Any resolution to your problem? I just rebuilt my engine and my stock boost gauge isn't working. My turbo is spooling but I wonder if it has anything to do with me shimming my wastegate. Don't have any engine codes either.

So I put my wastegate back to stock, and I had to adjust my cps to be able to start the car. I took it out and I couldn't get higher than -4 inhg on the boost gauge. Any thoughts?

 

[gotsomegetsome]

maybe your wastegate is jacked up? stays open under any vacuum, like if you messed with the wastegate spring and forgot to put it back it or something?

just a thought..

 

[ben1984j]

Any resolution to your problem? I just rebuilt my engine and my stock boost gauge isn't working. My turbo is spooling but I wonder if it has anything to do with me shimming my wastegate. Don't have any engine codes either.

Yeah I forgot to update this thread, it did turn out to be the wastegate. I guess my actuator spring was really worn out and I stretched it out by shimming it, then when I put it back it was too weak to do its job and hold the wastegate closed. I actually ended up fixing it by shimming it back to the same amount I'd done before (where it was overboosting and going to 14-15 psi)...except now the wastegate opens at about 8psi. I'm sure my spring will completely wear out eventually but since there's no replacement short of buying a whole new turbo, I'll just have to make it work until I decide to upgrade.

So I put my wastegate back to stock, and I had to adjust my cps to be able to start the car. I took it out and I couldn't get higher than -4 inhg on the boost gauge. Any thoughts?

This makes me think you're having the exact same problem as me. My car would at least start but it had a lot of trouble idling and did die a couple of times at stoplights. Exactly the same symptoms as a vacuum leak, right? And I'm pretty sure, since the wastegate is supposed to be closed at idle, that if it stayed open (due to a weakened spring) that would effectively be a vac leak (someone please correct me if I'm wrong).

So you might try putting the shims back like I did. Also, I wouldn't worry too much about the stock boost gauge not working, I'm sure you probably just forgot to hook something up or something but it's not worth the trouble of tracking it down; the stock gauge is unreliable and besides it only goes to 8psi, you should just put in an aftermarket gauge.

 

[cjsupra90]

with a bit of inginuity, you could use a standard garrett T3 style WG that turbonetics and many others sell. It just requiers a bit of fab to make a bracket for it....

 

[ben1984j]

with a bit of inginuity, you could use a standard garrett T3 style WG that turbonetics and many others sell. It just requiers a bit of fab to make a bracket for it....

That's interesting, I had heard it was possible to make an aftermarket wastegate work but I didn't know it was that doable...

 

[bglover84]

Yeah I forgot to update this thread, it did turn out to be the wastegate. I guess my actuator spring was really worn out and I stretched it out by shimming it, then when I put it back it was too weak to do its job and hold the wastegate closed. I actually ended up fixing it by shimming it back to the same amount I'd done before (where it was overboosting and going to 14-15 psi)...except now the wastegate opens at about 8psi. I'm sure my spring will completely wear out eventually but since there's no replacement short of buying a whole new turbo, I'll just have to make it work until I decide to upgrade.




This makes me think you're having the exact same problem as me. My car would at least start but it had a lot of trouble idling and did die a couple of times at stoplights. Exactly the same symptoms as a vacuum leak, right? And I'm pretty sure, since the wastegate is supposed to be closed at idle, that if it stayed open (due to a weakened spring) that would effectively be a vac leak (someone please correct me if I'm wrong).

So you might try putting the shims back like I did. Also, I wouldn't worry too much about the stock boost gauge not working, I'm sure you probably just forgot to hook something up or something but it's not worth the trouble of tracking it down; the stock gauge is unreliable and besides it only goes to 8psi, you should just put in an aftermarket gauge.

Thanks for the reply! So I ended up getting a boost gauge from my work that goes from -30 inhg to 30 psi and it showed that I was getting good vacuum (about -19 at idle) and whenever I would hit it with a decent amount of throttle I could only get up to about -4 inhg, which is where the stock gauge starts at. So i'm guessing my gauge works but I'm leaning more and more to my wastegate spring being worn out like you described.

I guess i'll try shimming the wastegate back and see if I can get my wastegate to operate properly. In the process of checking things the other day, another one of my 20 year old ventilation hoses decided to crack and break, so I need to replace it before driving the car again but i'll let you know if i'm successful later this week.