Reading into LTFC figures.

[Dave Zug]

you are right it only sees one side of coarse. a bung welded into the other
manifold and install a second sensor and you can put the wire ofer there for
comparison.

I've seen cheap EGT sensors for aircraft that have 2 probes. less than $100
used. 2-cycle motocross engines sometimes tune using them I beleive. This
will tell you if there is an imbalance. one of those cool laser temperature
detectors pointed at the header tube at startup can tell you if one is
misfiring too. a squirt of water on the headers does it too at startup.

I would think that unburnt fuel mixture would contain MORE oxygen than
normal therefore artificial lean.  is my logic messed up?


----- Original Message -----
From: Ross Myers <ponty at axis.jeack.com.au>
To: GM ECM List <gmecm at diy-efi.org>
Sent: Tuesday, January 16, 2001 4:49 AM
Subject: Reading into LTFC figures.


> Hi All,
>
> Been doing some ECM logging lately (which is O.K as far as the greenies
> go!!). Anyway, the LTFC values on my car tend towards the calibrations
> possibly being too rich, with most of the LTFC numbers down around 117 or
> so.
> But I am wondering. This is a single O2 system on a V8, so the left bank
is
> really determining the overall mixture readings, correct?.
> What if 1 cylinder is not firing nicely and is tending to drive the O2
> readings rich.
> How can I determine if it is a Calibration issue, a lazy O2 (although it
> seems quite active on the data I'm getting) or a slight misfire?.
> I'd like to somehow establish the motor and sensors are 100% mechanically
> O.K before I go taking out fuel in the cals.
>
> Thanks,
> Ross Myers
> Melbourne, Australia
> E-mail : ponty at axis.jeack.com.au
> Stuff : http://www.jeack.com.au/~ponty
> <><><><><><><><><><><><><><><><><><><>
>
>
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