1987 Audi 5000cs low boost // more info

Eric Huppert ehuppert at hvc.rr.com
Fri Jan 17 17:41:31 PST 2014



Seeing as how my son didn't provide particulars ref his low boost problem!


Car has an IA ECU. He's also tried the other modified ECU he has.


Has heavier wastegate spring.


Don't believe any codes. Wastegate moves freely, clunks as it should.
Diaphragm was replaced previously. (moot point, bad diaphragm creates over


Tested/repaired WOT switch. Working properly!


Disconnected Multi func sensor to ensure overheat signal not being sent!


Michelin man hose good.  Car has one of my old 20v intercoolers and BPV
installed. BPV is good. No apparent boost leaks


Switched out waste gate solenoid, no change. Need to further test. But,
would think the stiffer wastegate spring would apply a little more pressure




Aftermarket exhaust system, no cat etc. definitely no restriction


He previously had some hinky boost controller going to wastegate. I believe
he lost boost with that installed. So guess that would eliminate the
solenoid. That set-up (Ben Swan ECU) would push apx 20 lbs.


Doesn't have excessive endplay on turbo cold side


He's currently planning on sending out one of my 20v K24's to have it
freshened up (smoke at extended idle) if we determine it's the turbo



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