Posted By: Marty Longlade
Repeated Turbo Failures - March 18, 2002 12:33 pm UTC
I'm stumped with this problem. In the past two years I've gone through 4 rebuilt turbos. Aside from one that failed due to poor workmanship the other three all failed the same way, after about 8,000 km - the locknut on the compressor wheel comes off and toasts the compressor blades. I assume it's got something to do with the back pressure when you close the throttle during shifts or slowing down after the turbo is spooled up. I'm told this is a rare condition. I've checked the following without any indication of problem
1. compression - reading 150, 150, 150 163 peak (several revolutions)vacuum at idle- just under 20 psi & steady
2. by pass valve- opens at 15 in hg and pulses open when you you close the throttle- compared the amount of movement with another and it's identicle
3. waste gate actuator - moves at the required 11 psi
4. actuator hosing - no leaks
5. Electronic boost control - the on/off valve works , and is normally open at idle (dumping wastegate pressure signal to intake)- no idea what the computer is telling it to do during operation
6. Oil pressure is within proper operating range
7. No backfire evident
The turbo rebuilds were done by reputable company(s)- (I switched after the third failure) but now I've got to admit there's something wrong with the engine/turbo - but damned if I can find it.
Oh yeah I've got a stock (except for K&N filter)92 Laser GL (AWD) with about 160K on the engine. My troubles started about 6 months after a head replacement.(the car not mine) but I don't think it's related.
After the latest failure I put a used turbo in running with the wastegate open until I figure it out but as you all know I NEED the turbo boost. I also installed a blow off set at 12 psi as I'm leaning toward back pressure fixes yesterday.
Any ideas would be appreciated as I'm reaching the end my rope not to mention $ I'm willing to shell out.
Thanks
Marty
1. compression - reading 150, 150, 150 163 peak (several revolutions)vacuum at idle- just under 20 psi & steady
2. by pass valve- opens at 15 in hg and pulses open when you you close the throttle- compared the amount of movement with another and it's identicle
3. waste gate actuator - moves at the required 11 psi
4. actuator hosing - no leaks
5. Electronic boost control - the on/off valve works , and is normally open at idle (dumping wastegate pressure signal to intake)- no idea what the computer is telling it to do during operation
6. Oil pressure is within proper operating range
7. No backfire evident
The turbo rebuilds were done by reputable company(s)- (I switched after the third failure) but now I've got to admit there's something wrong with the engine/turbo - but damned if I can find it.
Oh yeah I've got a stock (except for K&N filter)92 Laser GL (AWD) with about 160K on the engine. My troubles started about 6 months after a head replacement.(the car not mine) but I don't think it's related.
After the latest failure I put a used turbo in running with the wastegate open until I figure it out but as you all know I NEED the turbo boost. I also installed a blow off set at 12 psi as I'm leaning toward back pressure fixes yesterday.
Any ideas would be appreciated as I'm reaching the end my rope not to mention $ I'm willing to shell out.
Thanks
Marty