My GVR4 Suddenly Not Boosting PAST 10PSI!! Any suggestions???

Yaa, just as I thought, took the arm off and it built no boost. Any other suggestions?

 

[belize1334]

How high did you rev it?

If it built zero boost, at WOT, well into the higher rpm range, then it's not your waste-gate. tdo5 turbos have trouble keeping the boost down, not up.

You could have a bad exhaust leak before the turbo (i.e. head to manifold gasket or manifold to turbo gasket). Do you hear a loud ticking when you get on the throttle? That's a sure sign of head to turbo gasket failure.

You could also have a severely plugged up exhaust system.

Lastly, it's still possible that you've got a boost leak somewhere. Maybe your blow-off-valve is opening prematurely and venting the boost above 10psi.

 

Yes I went high up into the RPM range at WOT and still Zero boost. What should my next stops be?? Boost leak? Make the setting on the BOV harder?? I did not hear a ticking noise.

 

[belize1334]

Yeah, I'd say you definitely need to do a boost-leak test at this point.

 

My buddy has 3 exhaust bolts stripped on his exhaust mani w. A major leak at the manfold and head and still boost to 22psi to what his psi is set to. Wouldn't the turbo try to spike and still compensate and build more boost if their was a boost leak?

 

My buddy has 3 exhaust bolts stripped on his exhaust mani w. A major leak at the manfold and head and still boost to 22psi to what his psi is set to. Wouldn't the turbo try to spike and still compensate and build more boost if their was a boost leak? Would changing the actuator arm help?

 

[belize1334]

When you pulled the actuator arm off, was it pretty stiff? Try pulling the arm toward the drivers side (in the way that it would move to open the wg) and see how much resistence there is. It's possible that the actuator is just broken and not able to hold the flapper shut. But that doesn't explain why it's able to build up to 10psi or why you don't get ANY creep with the arm off.

If the boost leak (not exhaust mind you) is bad enough your turbo will overspool and not be able to keep pressure in the pipes.

Does it buck at all when you build 10psi? Could it be hitting fuel/timing cut or something like that?

 

Nope doesn't buck, doesn't hesitate drives perfectly fine. It just doesn't go past 10psi. Ya there was a lot of resistance to put the arm back on the flapper.

 

[belize1334]

Resistance indicates that the spring is still in good condition. You want that.

Do a boost leak test and report back on the results.

 

No problem, will do.

 

[ercp98]

sorry to jack... but some what related. belize, what if it does buck/hesitates once it gets to 10psi? the boost holds, i just let the throttle go in fear that i will break something in the engine.

 

[belize1334]

Bucking is a sign of inconsistent ignition. If your ignition timing is severely retarded that can happen. Or if your spark gap is too wide or your plugs are fouled, etc... There are all sorts of reasons but none of them waste-gate related.

 

[1990ggsxnj]

You previously stated that the car seems quieter. Could that new cat have given out causing an exhaust restriction which is preventing the turbo from spooling normally?

 

[belize1334]

Good point. If the boost leak test doesn't tell you anything you might trying dropping the exhaust from the dp back and taking it for a spin. It'll be loud as F*ck but if you take it where nobody will yell at you then you can see if it boosts normally under those circumstance. Also, if you can just unbolt the CAT then you should be able to look through it and see if it's clogged or wedged.

 

[AnotherNewb]

Never heard of a WEDGED converter?! Is that like a lemon wedge or a pitching wedge?

 

[belize1334]

It's like a piece of something that gets wedged sideways inside something else. In this case, the element get's wedged sideways in the housing after first breaking up due to bad design or some debris and is then packed in due to exhaust back pressure.

 

[1990ggsxnj]

Exactly. I've personally seen 8 valves burnt because the honeycomb did just that. Almost complete blockage will build A LOT of heat.

 

Soo.... hooked up a vacume tester to the wastegate and it was not holding vacume, therefore im assuming the diaphram is shot? I also tested the vacum on the bov, and it did not hold vacum aswell, is the bov suppose to hold vacum?


Next I did a boost leak, now tell me why i felt air blowing onto my leg!!!!!

on the side of the intercooler where one of the welds are, their was an opening, pretty much cracked through the weld!!!

Anyways put some epoxy back on their for now until I weld it back shut this week and still not boosting past 10psi. I realize the car definately got a lot louder when the fmic was closed up, and I can hear the cam lobe now

 

[1990ggsxnj]

If the BOV is not functioning properly you could be rerouting while under boost causing this. As far as the wastegate not holding Vacuum, I would think you would be OVER boosting if that was the problem. Then again, if both of these are happening at the same time (overboosting but BOV recirculating the extra boost) than your turbo is working extra hard.

 

I have a gm maf, does that make a diff?

btw i tightened the bov and still tested the vacum and it was not holding...