** Sudden Jerk and Now Turbo WHIRS **

[Texas_GST]

Hey I have straight hounded the forums all day and could not find anything similar to what I have. A couple of days ago I had to accelerate pretty heavily to get into traffic flow, and about mid way through second gear, the car made a quiet jerk and the turbo now makes a very loud whirring noise. It starts as early as 2300 rpm and I tried boosting very slowly to see what happens and it sounds just like my turbo is spooling up normally but very very loudly, and that's with the windows up. It only boosts to 2-4 lbs and like I said, not the same mild whistling sound, it now whirs up, and also back down with the rpms. I took off the BOV because a buddy of mine has a couple of 1st gens and said he had the same noise and the cause on his were a faulty BOV. I cleaned it, reinstalled it, and same problem. Any ideas?? If im not clear on the noise, its like the old toys you would blow like a whistle but instead it makes a vroo vroooo vrroooooooo noise?? I dont know how else to explain it.

 

[nuclearr]

have you check all your intercooler pipeing?

 

[1gDSM4g63]

Sound you there is shaft play in the turbo.

 

[Jeff99GS]

Sounds like a boost leak. Do a boost leak test.

 

[Texas_GST]

So im hearing shaft play and boost leak. I have checked all my piping and everything is secure. I cant get to a boost leak test until a couple days but I have the car parked right now. If its shaft play, which im thinking is the worst thing, is my turbo screwed? And how could this happen just suddenly out of no where?? I have never had problems like this before until that day.

 

[matthewdesigns]

The sudden jerk was probably fuel cut due to a largish boost leak. Merely visually checking and/or touching each coupler will not do you any good, as you may have blown a hole in one. Do a boost leak test as soon as possible, make sure your turbo inlet tube/pipe is secure, and that your MAS plug is firmly seated (although those last two would cause problems even with idling or running at all...never hurts to check).

You can check for shaft play in the turbo easily. Remove the compressor inlet tube/pipe and grab the nut on the front of the compressor wheel. If there's any in/out movement you may have issues, but a little side to side is OK as long as it doesn't touch the housing. Look inside the housing with a flashlight and see if there's any scoring next to the compressor blades, if so you are looking at a rebuild or replacement. Contact with the housing could cause the noise as well as the spool up problem. On the other hand, so could a massive exhaust leak.

 

[wishnfor4g63T]

First of all - It already sounds like he has an aftermarket BOV.

Is your BOV recirculated?

Do you have a boost gauge aside from OEM?

When u boost does your boost gauge hold boost?

Do you have a Manuel Boost Controller?

1st things to check really simple check the turbo for shaft play hell it's just the t-25. You could upgrade to a small 16g for nothing.

2nd go around every coupler and tighten it down it won't hurt i promise.

3rd if you get really worried have someone boost leak test it with soapy water. if the problem doesn't arise report back here with your progress!!

 

[Texas_GST]

Yeah sorry it took so long but I have the Blitz Dual-Drive bov. Checked all piping but everything is okay there. Im doing a boost leak test tomorrow. One thing I found was a loose bolt from the flange to the turbo. Would that cause a boost leak? Its a little stripped so i didnt tighten it too much.

 

[Rob10_99]

Flange to the turbo, the J pipe or the exhaust manifold?

That whirr your hearing, is most likely your compressor scraping the housing, which is bad.
When my ebay 16g was going out, (redundant I know) it built 1psi boost at anything past 1500rpm. Incredible right?

 

[Texas_GST]

Sorry its the flange to the manifold. Im getting ready to do the boost leak test and I will let you guys know what I find. Thanks all.

 

[matthewdesigns]

When you do the BLT, take a moment to check out the compressor wheel/housing. Inspect both visually and by feel whether or not you have housing contact with the compressor wheel. If it's OK, then you can probably blame all of your problems on the boost leak/s you'll find and the blown gasket. Buy a new manifold to turbine housing gasket (multilayer not solid) to fix your exhaust leak. I had a similar leak (turbo to o2 housing) and it sounded like my cutout was constantly open...I could hear the turbo spool up and down all the time. A manifold to turbo leak would account for both the 'whirring' sound and slow spool.

 

[corsair231]

Make sure when you do the boost leak test to physically wiggle your hoses too. I've seen cars that would have a split hose that would not leak until the engine was running under load. The little bit of movement the mounts allowed would stress the split enough that it would open up. I've never seen it happen anywhere but at the end of a hose though.