All O2 sensors created equal?

[woody80z28]

In the 94 Silverado $0D with Vortec heads?

Yup. I had to add a lot of AE to get it to run right, and right now I'm at a compromise where it's too much in the summer and not enough in the winter. So the MAT should fix it in theory.

Right now I can watch my wideband be good on the throttle, let off to shift and it spikes rich (probably from the fuel being sucked off the intake walls) and when I get back in to the throttle after shifting it takes a few seconds to come back to stoich after going lean upon throttle reapply. I'm guessing fuel sticks to the walls again. On a hot day as I give it a little throttle to let out the clutch it will go rich on throttle apply and after a shift it will be a little rich on throttle apply too. It's a little better now with the thermac than it used to be, but still not good.

[EagleMark]

Probably because the $0D bin was auto trans... loads of differences in throttle follower, decel enleanment etc... to manual.

If your WB is set up to 0 to 5 volts it will also drive you nuts! Even if it were perfect you'd never know... 1 volt and Lambda works so much better in data, still an issue with most gauges...

[woody80z28]

Wideband is 0-5, yes. I watch it on the gauge when not logging. There were trucks with manual trans from the factory...did they not run $0D? I know the timing table was awful to start with and a manual trans LT1 table was much better right off the bat.

[dave w]

Wideband is 0-5, yes. I watch it on the gauge when not logging. There were trucks with manual trans from the factory...did they not run $0D? I know the timing table was awful to start with and a manual trans LT1 table was much better right off the bat.

I'm thinking the Manual Trnasmission would most likely be $31 or $OE. I've not seen a manual $31 or manual $OE. According the BCC spreadsheet I have these .bin should be manual.

BHDB

BHDC

BHDD

BHDF

BHDJ

BHMK

BHML

BHNB

BHNC

BPRH

BPRJ

BPRL

BPRW

BPRX

BPRY

BPSA

BRCZ

BSWW

I also think the PCM #

16156930

was used for manual transmission?

dave w

[EagleMark]

We went through this before and the manual trans trucks were not 16197427 or $0D, more like a older C3 ECM.

Now supposedly there are 16197427 5.7L Man trans bins in 1994-95 in G vans and P trucks. But we've never seen one? Also I have a 16197427 PCM that came with $0E, so who knows?

[daleulan]

Going back a couple pages.... TBI engines generally had a thermostatic air filter installed for fuel evaporation reasons (emissions, throttle body icing) and so in the stock air system configuration most of the time the inlet air temperature was basically relatively constant. Some passenger car versions used an IATS (my 1989 Caprice Classic did), but the pickup trucks did not. If they didn't need it for emissions it would be left out. Modern controllers have models now so that if the coolant temperature sensor or air temperature sensor is bad they infer a value and the models can be surprisingly accurate. Ours are usually within about 5 C of the sensor value.

[EagleMark]

Going back a couple pages.... TBI engines generally had a thermostatic air filter installed for fuel evaporation reasons (emissions, throttle body icing) and so in the stock air system configuration most of the time the inlet air temperature was basically relatively constant.

Thermac! Warm air from exhaust manifold.b Works very well for a crude mechanical device. Some guys remove it and run a straight cold air intake, horrible idea especially in cold climates. In warm climates or when hot it's closed anyway.

[woody80z28]

Yeah, mine is definitely better with the Thermac, but still not great. I would guess that's because my carb intake does not have the coolant passage under the runners like a stock TBI. I have thought about picking up a BBC adapter with the coolant passage.

http://www.ebay.com/itm/Chevrolet-GM...183#vi-content

[EagleMark]

God does not make mistakes, but GM does... man that is ugly! It was an adapter for TBI engines of that era because the same engine was used with a carb in bigger trucks and TBI in smaller trucks, they added hot water for icing. Not sure it would help? Do you only have issues cold? Headers?

[daleulan]

We all make mistakes. Half of us probably wouldn't be around if it weren't for mistakes....

Seriously, though, my new engine management software is so superior to the stuff I wrote a decade ago, but I still find things that I need to improve. And most of those are mistakes in understanding the physics behind the algorithms, not actual algorithm mistakes.

[EagleMark]

Tuning a car yesterday in Open Loop with the Wide band and a weather front came in. I had noticed where I put in fuel I was now taking out? Looked in logs and Barometric pressure had changed by 5... I was always aware but never had it happen during a tune!