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Had the car out for a spirited drive this afternoon on some back roads, while shifting from 1st to 2nd @ 5500rpm I had what sounded like a big dump of air. I pulled over, popped the hood everything looked fine.
Car starts, idles, drives fine, no weird noises but doesn't seem to build any boost.
I checked the bypass valve, holds vacuum and moves freely.
Also scanned for any codes- none
Vacuum lines seem to be all attached.
Any other ideas?
Check the large vac hoses down the back of the intake / same for check PCV hoses.
We saw one where MAF had 2/3 fallen off intake tube down in the fender and caused that.
Another would not make boost with one EGR signal hose melted on the EGR tube.
While we've yet to see it, another shop owner told me that had one in with failed intake gasket that did similar but ran ok out of boost.
All the vac and pvc hoses are in place, me leaks that I can tellQuote:
Originally Posted by ZR
Maf is in the stock location so it's all good.
EGR hoses are a fine also.
Would there be any visible signs if the intake gasket failed?
Also where would the air release too? Sounds like it went out the exhaust.
To me, if intake gasket not holding boost more likely vs not run poorly under high vac / light throttle.
Sure bypass valve is closed?
If yes, maybe pop EGR off or at least pull the pipe off it (one that runs to exh manifold).
Bypass does open when idling, and will close if the vacuum is removed from either the valve itself or from the top of the solenoid.Quote:
Originally Posted by ZR
If the bypass is force closed, should/would it start to produce boost at idle?
Should make enough at above idle rpm to here where your leak is (I've never tried it though).
Another thing to look for, possible intake bolt broken (intake to cyl head, not blower to intake). Even if all look ok, use a magnet or needle nose to give em all a lil tug.
How did you make out?
Well I checked everything you mention, all seems tight with no leaks.
Took it for a drive yesterday afternoon and the boost seems to be working again, so not sure what the issue is.
After doing a bit a reading the only thing that it might be is the solenoid that controls the bypass actuator. I guess it's meant to open the bypass if the boost exceeds the factory limit at WOT.
Might look at replacing it just in case. Seems to be lots of threads on eliminating or bypassing the solenoid but I'm not sure if I'll go that route
Good to hear all under control.
Being as it could just as easily be an absolute fluke, maybe monitor n only make changes if it repeats.