1992-1999 Series I L27 (1992-1994 SE,SLE, SSE) & Series II L36 (1995-1999 SE, SSE, SLE) and common problems for the Series I and II L67 (all supercharged models 92-99) Including Olds 88's, Olds LSS's and Buick Lesabres Please use General Chat for non-mechanical issues, and Performance and Brainstorming for improvements.

Vacuum Leak?

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Old 05-19-2007, 04:35 PM
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Default Vacuum Leak?

Since the new supercharger is installed on the car, I can hear this new hissing sound.
I bought a can of TB cleaner today to try out, with the car running i can literally soak the hell out of every Vacuum line and not get a single stutter, however, It almost seemed like it stutterd a bit if i spray the base of the Supercharger on the firewall side of the SC. Is it possible my SC is leaking were it seals to the lim? The hiss is still audible under load, and it is causing KR at the top end, I can see the numbers climb, and I can also feel it, never ever did this before, and i know it has nothing to do with ambient air as it has been cooler this week than the three previous.
Codes my car has pulled since the first day it was on the road is
DTC P0171 Fuel Trim System Lean
DTC P0172 Fuel Trim System Rich
DTC P0300 Engine Misfire Detected
DTC P1441 Evaporative Emission (EVAP) System Flow During Non-Purge
More often than not it pulls 171 and 1441 at once. However, now and then its just 171, and sometimes its all three. These ALWAYS come on now after each restart within 5 mins of driving. Before the new supercharger these rarely came on, generally when it was only really cold outside, even then, not every single day every single time like it is now.
Car ran excellent, pulled NO KR and had around 18 degrees of timing, constantly.
I also have tried two sets of plug wires and all, you cant feel a miss fire at all.
WTF?
Old 05-19-2007, 07:00 PM
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Okay, So upon further instpection all afternoon with FSM in hand....
All Vacuum is correctly connected.
MAF was a bit dirty cleaned that as per directions, cleaned the IAC
as per directions, inspected the PCV and changed it with one of my many new ones.
Cleaned both ends of the Positive battery cable.
Watched the Aerforce values for Short Term/Long Term with engine full hot and with the MAF disconnected, went for a drive..hmm..thats odd...car feels like it has ALOT more power with the MAF unplugged at wot...timing stayed higher, KR stayed at 0...once it got good and hot it pulled a bit more KR 1-2 degrees, 14 degs of timing..but still felt better..re connected MAF, car still feels pretty good.
Had my dad listen to the car, he said, that hiss doesnt sound like a hiss, it sounds more like the air intake...he figures im worried over nothing, as a vac leak would cause the car to run crappy and pull mid range KR, which, it does not.
I never checked the fuel pressure today, I know its high at all RPM ranges, which my FSM says will set a PO172.
PO171 hasn't come on for about an hour now, we can only hope I solved that one.
PO300? Can be related to the PO1441 Issues...possible EVAP switch or Solienoid issue? Book Mentions that also, I did as many tests as possible without a proper scan tool..not as easy..not as acurate, but it gives me a good idea.
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