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T77911S T77911S is offline
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Join Date: Oct 2006
Location: MYR S.C.
Posts: 11,163
Originally Posted by quattrorunner View Post
. The afr I'm talking about is about 15-15.7afr.
you have an AIR LEAK.
i have chased the SAME problem for a YEAR! my afr was in the 16's, (16.5) when i got the car. i found air leaks in the rubber boot that connects the turbo to the IC, pressure side. i found my WG valve guide had an air leak and my intake had an air leak. i even put NEW injector blocks on. car ran SUPERB for about hallf an hour. once i had it run great for about 2 hours, kept the RPM's low and drove like an old lady. afr's were around 14.7-15. then they started to go up just like yours. baclk up to 15.7. i have pulled the intake for the 3rd and final time to put on aluminum injector blocks. i found the intake flanges looked like a pringles potato chips and so do the injector blocks. i will try to get a pic of them.
either way, you have an air leak. i also found my throttle plate was not closing completely so my retunr idle was not consistant, but you dont have the throttle switch like mine.

my control pressure and sys pressure just dropped about .3bar. changing my fuel filter, i think my old one was clogged. hard to blow thru compared to new one.

what confused me is that the AFR would get leaner as the RPM's would go up. i finally realized the engine is asking for more air at higher rpm so more air leaks in making it leaner.
my boost is also rich.
also my boost would hit .9bar then drop to around .8 in like 3rd gear. i think it was losing pressure due to leak.

i checked my brothers AFR's under the same conditions were mine was lean. his was rock solid across the RPM band.

my problem was when i put the injector blocks on my intake was already warped. with th eheat cycles, the intake and the blocks just warped more.

one other thing. i was having to drop my control pressure to get AFR's in the low 15's. when i fixed the air leaks, i was able to run spec pressure, for a short while. now all my pressures are low due to fuel filter.
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Old 04-23-2014, 11:37 AM
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