[cac0274]

Need help from experts here.
87 GN stock with 87k miles
Parked the car 6 months ago ran great, started up a week or so ago and when it hits 3000 to 3500 rpms it starts to cut out, then turbo dumps out the waste gate.
I tried,
New Walbro 255, new sender, new gas tank. no change
New MAF sensor (aftermarket) no change.
New plug wires no change,
New coil a few years back.
I thought I was lacking fuel so I installed Walbro, I have 45psi plus all the way up to the cut out/engine sputter, so eliminate the pump as the issue.
Is my turbo shot? Any thoughts on helping me diagnose is appreciated. I am lost at this point.

 

[cac0274]

Any help on my potential turbo issue is appreciated

 

[Steve C]

Any help on my potential turbo issue is appreciated

I would try a scan tool or "Buick Grand National" on Facebook. Vacuum Leaks? Turbo impeller feel loose or wobbly?

 

[grandn86]

Have you by chance removed the tube that goes between the front of the passenger's side valve cover and got to the turbo bell?
I removed mine and installed a K/N filter in the valve cover hole. I had a problem with the turbo sucking oil into the turbo thru this hose. I had to take the turbo apart and remove the burnt oil deposits on the turbo shaft, then replace the brass bushings. turbo ran great ever since. I found a rebuild kit from Detroit Warehouse. Every turbo shops wanted me to buy a new turbo and send them my turbo for core exchange. be sure to use a set of micrometers to make sure you don't reduce the diameter of the shaft. Good luck

 

[cac0274]

Thank you guys, I will try the suggestions

 

[cac0274]

Thank you guys, I will try the suggestions

I checked all vac lines and did find the line that tees to the turbo wastegate off, started car up and ran up to 3500 rpm, them the same engine cut out happens, it blows the above vacuum line off. Something is causing pressure build up. I am at a loss so any ideas I will try.

 

[Steve C]

I checked all vac lines and did find the line that tees to the turbo wastegate off, started car up and ran up to 3500 rpm, them the same engine cut out happens, it blows the above vacuum line off. Something is causing pressure build up. I am at a loss so any ideas I will try.

Zip Tie that vacuum line.

 

[IL KIM]

Not sure but you might want to check your crankshaft position sensor - make sure it’s not rubbing the crankshaft pulley and that the pulley bolt is tight so the pulley is not walking away from the sensor, and look at pulley/belt as it spins while you give it a little throttle for any alignment issues. Good luck.

 

[turbomonte2]

Need help from experts here.
87 GN stock with 87k miles
Parked the car 6 months ago ran great, started up a week or so ago and when it hits 3000 to 3500 rpms it starts to cut out, then turbo dumps out the waste gate.
I tried,
New Walbro 255, new sender, new gas tank. no change
New MAF sensor (aftermarket) no change.
New plug wires no change,
New coil a few years back.
I thought I was lacking fuel so I installed Walbro, I have 45psi plus all the way up to the cut out/engine sputter, so eliminate the pump as the issue.
Is my turbo shot? Any thoughts on helping me diagnose is appreciated. I am lost at this point.

I'm no expert by any means, but I suggest you check hose connections for tightness from turbo, to/from intercooler, thru to throttle body. Sometimes a connection can come loose under pressure--but look ok when later inspecting under no-boost conditions. You don't really need ask me how I know this...

 

[turbomonte2]

I'm no expert by any means, but I suggest you check hose connections for tightness from turbo, to/from intercooler, thru to throttle body. Sometimes a connection can come loose under pressure--but look ok when later inspecting under no-boost conditions. You don't really need ask me how I know this...

OOps, I see I really need update my "Signature" here...

 

[PaCemkr86]

when it cuts out what boost level is this at or are you doing this at while in park?