Intermittened power loss (HP)

tillman speed

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If it was the bypass then I'd think it would effect your boost readings too.

Sounds like an electrical issue is about all that is left.. but I'm at a loss as to where or what system.

That's exactly it. It's all that's left. I wanna go over the wiring on everything with a fine tooth comb.
 

69Mach1-409

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I've been reading threads and watching dyno Vids sense last week! Cannot wait! :beer:

*Sorry for the mini threadjack*
 

tillman speed

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CR, what about the comment on the O2 sensor? Think it may be possible?
I just want to knock as many things out as possible before I bring it back to you (for both our sanity):boobies:

Maybe it's because it's the last half of the week and I'm retarted by Wednesday evening, but I just read through the whole thread and couldn't find the o2 sensor comment. The o2 sensors from what I see are fine, they're switching during closed loop, warm up pretty quickly, show commanded air/fuel ratio at WOT, etc. I think they're doing good. I didn't monitor actual o2 voltage, but the trims usually reflect any o2 issues. Yours are consistent, tight bank to bank, good to go IMHO.

Chris
 

69Mach1-409

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Maybe it's because it's the last half of the week and I'm retarted by Wednesday evening, but I just read through the whole thread and couldn't find the o2 sensor comment. The o2 sensors from what I see are fine, they're switching during closed loop, warm up pretty quickly, show commanded air/fuel ratio at WOT, etc. I think they're doing good. I didn't monitor actual o2 voltage, but the trims usually reflect any o2 issues. Yours are consistent, tight bank to bank, good to go IMHO.

Chris

Maybe I should reschedule my dyno run for Monday! :roflmao:
 

tillman speed

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you said u had a check engine light problem right? could your o2 sensor be bad causing the computer to see a differnt air fuel mix?? idk just throwing some stuff out there. My car did the same thing, felt strong one day and slow the other ended up being the temp the computer would timimg to save the motor. Mine was set at 95 now its 115 and its good.

Ahh... this?

I wish it were that easy. :(

Your o2 sensors send feedback to the PCM which generates what we call "fuel trims". These are the percentages that the computer calibration is off in order to obtain a perfect air fuel ratio at part throttle and idle (called "closed loop"). Basically your "fuel trims" are what the upstream 02 sensor reads and thats why you'll hear it called a "narrowband" o2 reading, because it's only accurate for such a short window. They're working great because your "fuel trims" are within 3% at all times throughout the whole scale. This is very good. It's because we took the transfer function (the table that controls the fuel trims accuracy) from TECHCO who built their transfer function in a labratory, so it's dead-nuts accurate. We had to skew it lightly for a few of your modifications, but the curve was right, just needed to be shifted a few percent.

The WOT air/fuel ratio isn't controlled by the upstream oxygen sensors. Regardless, the air/fuel ratio at WOT is perfect, so we don't have to worry about it. Fuel pressure was good, everything else looked wonderful.

I think we're going to laugh when we find out what it is. Your datalogs are picture perfect, though. I'd be willing to post them up if you don't care so that everyone can see that it was calibrated correctly.

Chris
 

05bluestang

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Ahh... this?

I wish it were that easy. :(

Your o2 sensors send feedback to the PCM which generates what we call "fuel trims". These are the percentages that the computer calibration is off in order to obtain a perfect air fuel ratio at part throttle and idle (called "closed loop"). Basically your "fuel trims" are what the upstream 02 sensor reads and thats why you'll hear it called a "narrowband" o2 reading, because it's only accurate for such a short window. They're working great because your "fuel trims" are within 3% at all times throughout the whole scale. This is very good. It's because we took the transfer function (the table that controls the fuel trims accuracy) from TECHCO who built their transfer function in a labratory, so it's dead-nuts accurate. We had to skew it lightly for a few of your modifications, but the curve was right, just needed to be shifted a few percent.

The WOT air/fuel ratio isn't controlled by the upstream oxygen sensors. Regardless, the air/fuel ratio at WOT is perfect, so we don't have to worry about it. Fuel pressure was good, everything else looked wonderful.

I think we're going to laugh when we find out what it is. Your datalogs are picture perfect, though. I'd be willing to post them up if you don't care so that everyone can see that it was calibrated correctly.

Chris

I don't care you can post them if you want. I agree, it's most likely something stupid that nobody would have thougt of looking at in a million years :ugh1:
 
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