2nd Generation Specific 1986-1992 Discussion

Boost Leak?

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Old Jan 9, 2005 | 10:27 PM
  #1  
MtnRacer's Avatar
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From: Grape town baby
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Ok, to abbreviate the story:



2003 turbo motor swap into GTUs, with 3" turbo back + AVCR - boosts to .6 bar fine except hits fuel cut past that



2004 haltech e6k install - wierd pinging problem under any manifold pressure, finally solved this last week(combination of plugs being too hot and ignition wired backwards)



So now that the car is actually safe to boost, I've been boosting it everywhere, but it hits a wall at .45 bar. No real loss of power, no stuttering, just won't rev past .45 bar(got it to .48 at the top of 3rd gear once). What gives? I just reseated the uim too with a fresh gasket, gasket sealer, and checked all vac. hoses to make sure they're not leaking. Adjusting the AVCR's boost levels doesn't affect my max boost. Any ideas?



Steve



P.S. .45 bar = 6.5psi

P.P.S. It's also been lumpily idling a little low(700rpms) ever since I pulled the uim off to check and see if my secondaries were bad(see aforementioned pinging problem), although this may be due to the different map I'm running now.
Old Jan 9, 2005 | 10:40 PM
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Well it won't studder if it was a boost leak, since its running a MAP, only suck through MAF studders. Have you pressure tested your intercooler system? If not you can usually tell a boost leak, by rollling your window down and boosting the car hard. Listen for a whislting sound, it's a very distinct sound, if you hear it you have a boost leak. If everything checks out ok, check how you can the vacum lines routed you should creep a little more with a 3" exhaust. Good luck!
Old Jan 10, 2005 | 11:05 AM
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Do you here a big hissing? I did when i had one.
Old Jan 10, 2005 | 12:56 PM
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Yeah. Back when I was piddling with my bypass valve plumbing, it was very obvious if it was leaking boost. You'll hear it unless you attended lots of Who concerts as a young lad.



I'm not familiar with the AVCR, but to me it sounds like your wastegate is bleeding off boost at pressures above .45 bar.
Old Jan 10, 2005 | 02:16 PM
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From: Grape town baby
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I don't think it's the AVCR because before the haltech install, it would boost to .6bar no problem. Unfortunately, there was a period of about 8 months after the haltech install where I couldn't boost it at all due to the pinging problem, and I'm not sure what happened in that time frame to mess up my boost. I'll listen for the hissing, but when I took it out, I didn't notice one.



Steve
Old Jan 11, 2005 | 08:38 AM
  #6  
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So then the question is do you even have boost leak? Like 1988 said above, it could be ur WG bleeding it off before you can reach full boost.
Old Jan 11, 2005 | 03:42 PM
  #7  
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From: Grape town baby
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Yeah, I'm starting to believe. Only one way to find out!!



If I want to disable the wastegate, can I just unhook the AVCR solenoid? Or do I need to get down and dirty and go to the wastegate itself to unhook the actuator?



Steve
Old Jan 13, 2005 | 07:12 PM
  #8  
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From: Grape town baby
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Turned out to be a bad ground to the AVCR. I forgot I rearranged some of the wiring when I installed the Haltech. Thanks for the help everybody!



Steve
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