Turbo Going Bad Question

[gmenor]

What are the systoms of a turbo going bad? I have decrease power - but boost is at 7 - 8 lbs with EGT spikes of 500 - 600.

[john8662]

A turbo going bad can lead to performance problems but is usually associated with a mechanical failure of the turbo. Things to check, pull the air cleaner boot that goes into the intake of the turbo compressor and check a few things:

1. How easily does the compressor wheel spin?

2. Do you have any sideplay?
a. If so, how much, and does the wheel contact the compressor housing?
b. Do you have any endplay (pulling and pushing on compressor wheel)?

3.Finally, binding wastegate lever, how easily is it to move the wastegate lever with the truck not running, should have some resistance (with actuator still attached) but move smoothly.

Those are the usual things to consider...

When checking the above suggested items, especially in respect to the play in the compressor wheel, be gentle! You don't have to tug hard, you'll be able to feel the general play if has much. Side play is normal on a turbo, there is supposed to be some, it becomes excessive when the wheel is allowed to contact the compressor housing.

[gmenor]

John,
Thanks for the reply but, all that you mentioned was done already. I guess should have elaborated that on the original write up. Anyhow, down to what I perceive as the symptons are sluggish response (fuel is good), higher and faster EGT climb rate, not the noticable turbo whistle. Again compressor wheel has little side play, spins like a champ, no noticable forward play and actuator arm is oiled regularly oil and moves freely.

[john8662]

Perhaps you're bleeding boost pressure somewhere. The upper intake piece to the lower intake could have a gasket leaking, or perhaps the boot that connects the turbo to the upper intake plenum has ruptured or is loose for some reason.

Are you getting smoke?

My main question here is what boost did you see before the 7-8psi, because that number is completly normal for a stock chip 6.5TD. Unless you have a boost controller or have an aftermarket chip, then thats all the boost you'll see. The EGT you're describing is also normal, where are you measuring the exhaust, pre or post turbo?

[ 08-22-2005, 05:31 AM: Message edited by: john8662 ]