F18Rep

Evening sportfans....My long streak of trouble free turbo miles came to an end about a month ago. Zero boost. After many hours searching old posts and trying everything mentioned with even a swap-in of a known good turbo I've just about accepted that either my wastegate suddenly failed and opens under mild pressure or I have a collapsed cross-over.

So.... its not completely obvious to me the chain of events when a xover fails but I'm theorizing that a collapsed cross-over restricts flow and thereby causes the WG to open against its 12 pound spring. That dumps all hot side pressure and no boost. Am I missing something?

Would it be possible to confirm the bad cross-over by disconnecting the output of the WG and reving the engine or making a quick pass up my country road? I'm guessing that I will hear it dumping. Suggestions?...Bruce
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No LED codes. Yes, the KLR sets codes via the test TPS disconnect code.
No boost even with pinched WG line.
Cold side pressure checks good, only thing suspicious is that pressure leaks out of the cycling Valve to J-boot line (guessing this is normal, since pinching it doens't help).
WG outlet is slow to heat up startup with idle only.
Nothing obviously wrong with the removed turbo
Just wished I woulda dropped a golf ball or something thru the crossover when I had it out.

Techno Duck

Have access to a bore scope? You can remove the wastegate tie in pipe and inspect.

ekoz

A quick way to test for bad wastegate is start car when cold. Touch exhaust quickly and see if wastegate tie in is getting warm. If it is the wastegate is failed open. If it's good the ties in pipe should be cool and you're exhaust will be hot. Again, caution should be taken not to burn your hands. The exhaust heats up very fast. A cheap laser thermometer can be used as well

Tom M'Guinn

Might be easiest to disassemble and inspect the cross-over and the cat pipe. Or you can check the back pressure using the port on the cross-over and/or seal off the wastegate with a sheet of copper in place of the wastegate gasket.

alxdgr8

Mine was the cat pipe...but I would at least get a couple psi, not zero.

F18Rep

Borescope - had just about blown off the idea of getting borescope but maybe if I could get a cheapie and it actually took me to the problem - it would be worth it.

Touch exhaust quickly and see... yea did that, it seems to pass this test. At idle, the wg exit stays cool enough to touch for at least a minute while the regular cat route seems to heat up pretty steady. Prices on infrared thermos are pretty low. will check into that.

Disassemble... Or you can check the back pressure using the port on the cross-over and/or seal off the wastegate with a sheet of ....
Hmmmm... I still have the little stainless tube that attaches to that port, so whatever happens that puppy is going back on.

Mine was the cat pipe.... I didn't even think about the cat bc mine is gutted, will have to look harder at that.

All good thinking, hope to have an update soon...Bruce

F18Rep

Found a tumor.... think this might be the problem?...Bruce

Tom M'Guinn

Looks like you found it -- nice work! (Even if something else is wrong, you want to fix that for sure.) Don't know what the smog laws are like for you, but if you're allowed to go with a test pipe, it will really help add power to the motor. Of course, coming from the pipe in that picture, a copper water pipe would probably be an improvement...

F18Rep

Yep, its fixed. Put on a spare cat pipe and boosting fine now (its also gutted). That pic isn't very good, the balloon is so big it reaches the opposite side wall (maybe 80% obstruction). If Alex hadn't mentioned it I prolly wouldn't have even looked there - and would have spent my day fighting the damn cross-over. A very easy fix to a difficult problem. Anyway thanks guys...Bruce

PS...
I may be out of date on the local smog laws but I think I'm still subject to a visual confirmation of the presence of a cat.

Van

I know you found your problem, but the discussion of testing the wastegate pipe temp on startup reminded me of this video - I use a thermal camera to look at the exhaust pipes. You can see how big a difference the double-walled pipe makes, too.

ekoz

And the Oscar for best visual effects goes to..................VAN!!