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Old 09-22-2009, 02:20 AM   #1
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Default Bad WB, MAP, or ???

My car was running fine until I ran into a series of problems -- first, the power steering pump main pivot bolt worked itself out (don't ask me how, since it has to go through the hole in the pulley of PS pump), and then I had some IC pipes that would not stay on. For some reason, the flange on the compressor outlet on my Garrett T28 seems very short, and I can only get a worm gear on there. I've tried 2 different types of T-bolt clamps, and they seem to just "squeeze" the silicone IC piping off. Anyhow, seems I got it on there snugly with a worm-gear clamp (which i had used for years without problem), but now I've got all these weird symptoms:

Now, my car's WB gauge at idle swings up and down a lot more than it used to (~13 - 15), and it just sounds off. When I get going, the WB seems to be reading as it used to, but as soon as I stop moving the gas pedal (steady state cruising at any speed), the engine is fluttering, for a lack of better descriptors, and the WB swings anywhere between ~10-17, and it drives horribly. If I press the throttle again, it takes a few seconds, but at whatever engine condition, it seems like the car wakes up again and runs normally. It doesn't matter if it's a cold engine or warm, same symptoms.

Vacuum leak? Bad WB sensor? Bad MAP sensor? Where do I even start looking?

Thanks for any help/advice.
BTW, my setup: AVO turbo manifold with Garrett T28 BBB, intercooled, RC550s, Magnecor KV85 wires, new NGK BKR7E's at 0.040" (replaced, no change in behaviour), TEC3 ecu (no recent changes).
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Old 10-01-2009, 03:46 AM   #2
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What I've done so far (without any result, obviously, or I wouldn't be emailing you! lol)

- checked the main ground to the TEC3 ECU (ground wire - I think it is - is directly connected to the -ve battery terminal).
- checked all the main grounding points in the engine bay.
- swapped out my wideband O2 sensor, re-installed a narrow band O2 sensor, changed the software for narow band, and re-flashed the computer.
- checked for vacuum leaks around the intake manifold - used unlit but freely flowing propane torch (supposed will make the car rev higher if propane gets sucked in through leak ??)
- checked the PCV valve -- good suction on the valve cover side, removing the intake manifold side causes the engine to rev
- new plugs, re-gapped to the old setting (.040")
- re-flashed computer with known good map.
- plug wires are Magnecor KV85s -- spoke with them, and they are 100% confident it's not plug wires. (?) Lifetime warranty against regular wear.

Here's the suspicious part: checked the newly installed plugs
** the plugs are black and sooty around the base (bottom of thread), and a little on the insulator; the ground electrode is quite white-ish grey (vs. greyish-white).
Also, the exhaust "smells" rich, with a fair bit of black soot, and even some, what I think is, water. May be condensation because it hasn't been run much in the last few week

Any ideas?

I've tried changing the target AFR, but doesn't seem to affect anything. Also tried re-mapping timing without any effect...
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Old 10-08-2009, 03:21 AM   #3
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OK, checked plugs again, and found that only #2 has black soot around the insulator. The rest are dry blackish around the base of the threads, where the electrode comes out. Probably more sinister (mechanical problem).

Anyone have any ideas?? please??
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