Hard Start in 96 454. Please Help, this is a doozy

[SAATR]

They are just there to verify catalyst functionality. Part of the emissions system and nothing more. They cannot affect the way the truck runs.

 

[SAATR]

What are your fuel trims at idle? Should show up and LTFT and STFT, Bank 1 and Bank 2.

 

[brycebba]

I took a little video since they were moving around a bit.

http://youtu.be/cupSKwSlfSE

- Bryce -

 

[SAATR]

I took a little video since they were moving around a bit.

http://youtu.be/cupSKwSlfSE

- Bryce -

Is the truck at operating temperature in that video?

Edit: Or more precisely, is it in closed loop?

 

[brycebba]

Yeah. Sat for about 20 minutes before but it's 93 degrees so it barely cooled

- Bryce -

 

[brycebba]

Sorry I'm new to this, what do you mean by closed loop

- Bryce -

 

[98_k1500]

B1S2 is either faulty or you have a wiring issue. Minimum voltage you should see from an 02 sensor is 0.1V. Bank 2 is rather rich, as max 02 voltage is around 0.9V, with stoich occurring in the neighborhood of 0.45V. They make exhaust backpressure guages that you can use to test for a plugged cat. The way our trucks' exhaust is built, it's not really feasible to drop the cats and run the engine as you would be running straight out of the manifolds, which will cause running issues too.

If the cats were plugged enough it wouldn run, It would sound like a jet engine out the exhaust, and the more throttle you gave it, the more it wouldn run. It will run smooth as glass, just the more pedal you give it, the weaker it would get.

 

[SAATR]

Sorry I'm new to this, what do you mean by closed loop

- Bryce -

Closed loop occurs after the engine reaches a specific temperature, usually somewhere below the opening temp of the thermostat. When you start the truck (or any vehicle) cold it's in open loop, which means that the ECM is running on a fixed set of parameters and isn't using the O2 sensors to adjust the air fuel ratio. Once it hits closed loop temperature, it starts using feedback from O2 sensors, MAF sensor, etc to adjust the air fuel ratio for emissions and performance.

 

[brycebba]

Ah, so any idea what the problem might be based on the video readings?

- Bryce -

 

[SAATR]

No. Your trims are within acceptable ranges for both long and short term, and your O2's seem to be switching properly. O2 output is better viewed as a graph, so that you can see the cross counts and the general range of sensor operation so that you can make sure they are working properly. You still don't have any codes?