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Performance, Brainstorming & Tuning Talk about modifications, or anything else associated with performance enhancements. Have a new idea for performance/reliability? Post it here. No idea is stupid! (please use Detailing and Appearance for cosmetic ideas)

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Old 11-27-2004, 07:06 PM   #71
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There'* not an issue of too much unmetered air passing by the MAF, is there? I think I worded that right... my buddy from the TCCOA expressed concern at altering the structure of the TB, and I just thought I'd throw up a post. Correct me or shut me up if I'm not making sense
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Old 11-27-2004, 08:49 PM   #72
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Wow, yeah... the cat was gone. Car sounds great now. I started her up with just open headers, That'* F'n awesome. While pressure testing the exhaust I found the hole I heard wasn't in the parts I played with, But in the pipes I had a shop do. Loverly.

It'* dark out so I'll be doing a little scanning in the morning. Car seems to run better and rev'* faster.
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Old 11-27-2004, 10:34 PM   #73
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Generally speaking (outiside of 3800'* even) timing advance is lower on a supercharged motor compared to the exact same motor with a conventional intake/carb. Hows your AFR looking? The MAF sensor still thinkgs you've got the normal opening, but adding 4k G/* will put you off by that much. on the AFR.

When i had my car fired up with an open pipe @ 2am it was sweet, but i had to keep it short lived.

I got a video somewhere...
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Old 11-28-2004, 11:00 PM   #74
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Reset the PCM and let it do a little learning, The car sounds great, idles smooth but lacks real power. I'm getting 02mV'* in the 20'* on WOT. I think I'll read the 50 or so pages in the FSM about the fuel system. Spark advance is down to 15* at idle, I'm not getting any KR at all. Seems to be running better, yet still lean.
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Old 11-29-2004, 01:00 AM   #75
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The FSM narrows it down to one of three things being faulty, the FPR, the Fuel Pump strainer, or the Fuel Pulse Dampener. I'll use trav'* car to test the fpr and hopefully not have to drop the tank again.
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Old 12-03-2004, 03:27 AM   #76
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Any luck here?
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Old 12-03-2004, 03:39 AM   #77
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Got ahold of Trav'* car today. Seems my fuel system is okay, It matches his exactly now.

I swapped back to the stock TB and watched the scantool for an hour or so. I have high fuel trims (LT 130-140, ST 130-135) yet low 02'* (15mV on WOT) and the PCM isn't trimming it higher. Reading the FSM more hoping I can figure out what it'* doing...... Anybody have any idea?

I had IAC counts in the 15'* with the MMTB, mid 50'* with stock. I was thinking vacuum leak but the stock TB gets me normal IAC counts... There'* something wrong, But it isn't Exhaust or Fuel. I'm thinking either a worn timing chain or a weak spark.

Tommorrow after work I've convinced dad to check my crank and cam sensors with his oscilloscope, should tell me if there'* alot of slack in the chain. (At least he says it will, I have no idea)
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Old 12-03-2004, 04:41 AM   #78
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Shot in the dark, but what are you plugs, and wire situation like?

Try swapping out coil packs with Travis Maybe?
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Old 12-03-2004, 05:18 AM   #79
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Quote:
Originally Posted by Damemorder
Got ahold of Trav'* car today. Seems my fuel system is okay, It matches his exactly now.

I swapped back to the stock TB and watched the scantool for an hour or so. I have high fuel trims (LT 130-140, ST 130-135) yet low 02'* (15mV on WOT) and the PCM isn't trimming it higher. Reading the FSM more hoping I can figure out what it'* doing...... Anybody have any idea?

I had IAC counts in the 15'* with the MMTB, mid 50'* with stock. I was thinking vacuum leak but the stock TB gets me normal IAC counts... There'* something wrong, But it isn't Exhaust or Fuel. I'm thinking either a worn timing chain or a weak spark.

Tommorrow after work I've convinced dad to check my crank and cam sensors with his oscilloscope, should tell me if there'* alot of slack in the chain. (At least he says it will, I have no idea)
What block is the LT trim on? ST trims are just fine tuning within those blocks. You could have an ST of 128 but if the LT block is 16 at idle you've got an issue.

Mid 50'* seems pretty high for the IAC count with the stocker, seems like a restriction the IAC is compensating for. I wouldn't be concerned much with the IAC though, as long as the change in idle isn't imediately after an IAC adjustment, its probably working fine.

15mv is excessively low at WOT, avoid WOT right now at all costs. That should be in the upper 800 to lower 900mv range. How did you compare the two to determine your fuel delivery was fine? I'd keep my left eye on it still. Have you replaced your o2? It might be ready for it if not. The PCM won't do any trim adjustments at WOT because it actually ignores the o2 sensor. It does math from the adjustments it makes at part-throttle/cruise and such. Like it figures if at 50% throttle it needs an 8ms injector pulse, at 100% it'll make it 17-18ms to be on the safe side. So try resetting your pcm and giving it 20min or so of part-throttle city cruising to relearn, see if that changes your o2 at WOT.

What are your idle o2 readings? Cruise readings?
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Old 12-03-2004, 06:04 PM   #80
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So for the sake of clarification, is it safe to say the TB modifications are unrelated to these problems? I'm interested in replicating the mod over Christmas, and I'm curious if there are long-term implications of modding the TB.
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