Wiring checked. Engine in. B1 02 error - lean. eeHack log attached. Paying bounty!

[atlantadan]

Hey Mitch - I'll check the plug leads. Plugs are new, though. If it were spark, would the 02's not read lean and instead read rich due to unburned fuel being pushed into the exhaust? The throttle body is a new Holley. No IAC drill hole at all - it's solid. Looking at the counts, it would appear that the ICV is working without the bleed hole, correct? Maybe I will try swapping over the older TB and see what happens.

[Terminal_Crazy]

Apparently not.
O2's only measure the Oxygen not the fuel. A misfire would read lean as you'd have 1 cylinder's worth of oxygen passing through.
1 plug misfiring would add 25% to the bank which on 128 would put the BLM's upto 160+
If that's the case you have at least 1 each side not firing & plugs would be wet.

MAF starts at about 15gms and drops down to about 7-8. Not sure what stock runs, I'm in SD but 7 looks a bit low so it presumably is getting enough air from somewhere.

What manifold have you got?


Mitch

[steveo]

i'd say first check for a bigass vacuum leak, loose intake elbow clamp after the maf, stuff like that. try plugging off every single vacuum port on the intake manifold except the FPR and spray around for an intake leak.

[steveo]

isn't your MAF airflow fairly low for an idling 383..?

[kur4o]

First you need to find out if the lean condition is real or fake. I have seen coolant fouled 02s reading always lean and mpg of around 2mpg.

Idle MAP is fairly high around 50-53kpa range. With low maf readings and engine speed is always higher than commanded might suggest a vacuum leak. Engine sucking unmetered air.
Bad tune is always possible reason.

Start playing with mode 4 control and you will nailed it pretty fast. Start by going open loop and monitor O2s reading, than start increasing aft target and monitor at what value 02s goes to 700-800mv.

Than you can play with cylinder deactivation. If there is no change in map and rpm when you disable a certain cylinder, it might be a suspect.

[atlantadan]

I want to say that you all are f-ing awesome for helping. This engine has been kind of a bear and I while I thought I knew what I was doing, its obvious that there still is a hell of a lot to learn. Thanks for your patience.

i'd say first check for a bigass vacuum leak, loose intake elbow clamp after the maf, stuff like that. try plugging off every single vacuum port on the intake manifold except the FPR and spray around for an intake leak. isn't your MAF airflow fairly low for an idling 383..?

Yes, I would think so, after looking at it. So that would be another pointer to a vacuum leak? I pulled everything off and checked with carb cleaner. Idle did not change, so if its leaking - it is in the valley.

First you need to find out if the lean condition is real or fake. I have seen coolant fouled 02s reading always lean and mpg of around 2mpg.

Swapped 02's and the problem stays on bank 1

Idle MAP is fairly high around 50-53kpa range. With low maf readings and engine speed is always higher than commanded might suggest a vacuum leak. Engine sucking unmetered air.

There's another vote for vacuum leak. Y'all are convincing me to pull the intake, and then re-install my original one to test.

Start playing with mode 4 control and you will nailed it pretty fast. Start by going open loop and monitor O2s reading, than start increasing aft target and monitor at what value 02s goes to 700-800mv. Than you can play with cylinder deactivation. If there is no change in map and rpm when you disable a certain cylinder, it might be a suspect.

I monkeyed with cyl deactivation as suggested and they all seemed to have the same effect: RPM's drop a bit each time. I don't know anything about Mode 4 control....

More testing today:
- Swapped injectors from one side to the other: No change.
- Swapped 02's from side-to-side (second time): No change.
- Used IR temp gun on headers. Found that 3 cyls on bank 1 are colder than bank 2 - which points to poor/incomplete combustion. Chose the coldest port from Bank 1 and the hottest port from bank 2 and pulled the plugs. Ran a compression test on those two cylinders and they were identical @ about 200 psi.
- Plug pulled from cold side was gray/brown. Plug pulled from hot cylinder was black, which indicates that its running super duper rich.

[kur4o]

I think that you will need a new tune with that intake manifold.
Individual air to cylinder passage are different by stock manifold.
Edelbrock must flow much more air than stock and the individual cylinder trims are off the chart.

Mode 4 control allows you to control realtime how the engine runs.
You can force open loop while the engine is running or change spark advance.
I advice you to start playing by that and see if the lean conditions exhibits only at closed loop.
Hint. Warm the engine, switch to open loop and lower the afr value, while monitoring 02s.

You might post your current bin too.