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

I will pay a bounty to anyone that figures this out. Cammed 383, 58mm tb, trick flow heads, CIA longtubes, cats. Every sensor on the engine is new.

Had the entire harness out checking it and nothing was really amiss, outside of the washer harness. Grounds are all really solid. Log shows a 100% cold start to open-loop.
Fuel pressure: 42 PSI key on engine off. 40 psi running @ idle. 12-15" of vac at hot idle.

02's look decent initially, but once the car enters closed loop, b1 goes lean, and the PCM starts dumping fuel in. Car eventually pops the 02 lean code, both fans kick on, and that's it. Clear the code and it comes right back after a few minutes. The after clearing the code, the left 02 continues to read like 50mv or something super low. Swapped 02 with a known good one. No-change. Raising the RPM's causes the 02 to start swinging, but once it hits idle, it goes lean again. Here is the log. Forum wont let me attach it.

Your assistance is appreciated.

Edit: No exhaust leaks. No vac leaks @ intake

Motor is just maxing out BLM's. both banks showing 160

Have you changed increased cylinder size and injector sizes? 350-383 approx 10% bigger
383 should be 783.70 cc per cylinder.

It's going into CL at 34 degrees which is probably a bit early.

VE Tables will need playing with (increasing to richen it up)

IF the 160 BLM is close (IT May be higher but we don't know) 10% increase on cylinder size and around 8 - 10% on the VE table would put you a bit closer.

You also have an Error77 fan 1 fault i'd look at fixing first or switch it off in the PCM for now

O2's should start offat 450mv and drop down to abound 5-10mv with just the ignition on as they heat up.
With Long tubes they need heat even though they have heaters in them.

OK seen the O2lean error and where you clear them, however both BLM's have maxed at 160... Needs more fuel.

Mitch

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Originally Posted by Terminal_Crazy

Motor is just maxing out BLM's. both banks showing 160

Have you changed increased cylinder size and injector sizes? 350-383 approx 10% bigger
383 should be 783.70 cc per cylinder.

It's going into CL at 34 degrees which is probably a bit early.

VE Tables will need playing with (increasing to richen it up)

IF the 160 BLM is close (IT May be higher but we don't know) 10% increase on cylinder size and around 8 - 10% on the VE table would put you a bit closer.

You also have an Error77 fan 1 fault i'd look at fixing first or switch it off in the PCM for now

O2's should start offat 450mv and drop down to abound 5-10mv with just the ignition on as they heat up.
With Long tubes they need heat even though they have heaters in them.

OK seen the O2lean error and where you clear them, however both BLM's have maxed at 160... Needs more fuel.

Mitch

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Thanks Mitch.

Engine is a 383, and I forgot to mention that the car was tuned by PCM Performance. I have a second PCM with a tune by Moe Bailey (also for a 383) - swapped it in and the issue persists, so I don't think the problem is tune-related. The Moe B tune was in there before and ran 100% fine. The only things different from then and now is the addition of a 58mm throttle body, and an Edelbrock intake. PCM Performance tuned it for the 58mm/intake.

Fixed the fan - forgot to put in a fuse.

Car smells pig rich at idle though. It'll almost burn your eyes. I'll pull the rail and put cups under each injector and crank it. Maybe something got into the rail while it was sitting on the bench.

Are you able to record TunerPro RT Data Logs or EEHack data logs?

Do you have Wide Band O2 Sensor installed?

dave w

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Originally Posted by dave w

Are you able to record TunerPro RT Data Logs or EEHack data logs?

Do you have Wide Band O2 Sensor installed?

dave w

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Hi Dave. The link to the eehack log is in the first post.

Some free-wheeling thoughts:
1. Intake and throttle body are new and were not on the previous install. Heads were pressure checked pre-install. Wondering if intake manifold is cracked or otherwise compromised? Could be creating a huge vac leak, which would force the PCM to add fuel. If the intake was compromised, seems to me that'd be easy to see with the vac gauge - which has normal readings. BUT.....
2. Looking at the log, that 02 reading on the driver's side tells me that something is jacked up over there. Maybe a clogged injector? I am going to swap injectors from one side to the other and see if it follows. If not, it's something specific to that side.
3. Both sides are adding fuel to the max, so even though the driver's 02 is showing lean, they're both being affected. The fuel rail and injectors were never disconnected from each other when pulled from the engine. I removed the rail and injectors as one unit and set them on the shelf in the garage, where they sat for 6-8 weeks. Wondering if something got into the rail and now whatever was in there has been pushed into the injector baskets, more on the driver's side than the pass. I'll have to go to Target and get 8 jars or glasses to test the injectors when turning the key. Don't know if that'll tell me much, but its worth a thought.

PCM still sees it as lean so will dump fuel in.
Lowest BLM in Cruising AFR is about 155.
Integrator is hitting 190's to try and compensate sets the fault off & resets back to 128
Injector pulse goes from 4.50 to 3.50 which won't help any.

Are the throttle body plates closed so all idle air is going through the IAC?
Plenty of Info about drilling them bigger or tubing them up to do this.
Some are better than others.
My stock TB is drilled out to 5.0mm

IAC starts at 158. By CL 135.
By 80 degreesC (i use 90 as the minimum) it hit 40's
When left just to idle it's around 80's.
I'd expect it might need drilling out a little but I don't think this is the issue unless the IAC is blocked or not actually operating.

TPS voltage sat at 0.73/0.71mV. again probobly OK. I think it seems to be right to have it set 0.67mV so near enough not to be an issue.

I'd check throttle body blades close fully or for the shaft bearings leaking unmetered air if this is the only change to the motor.

OR
It's not firing a cylinder or two.
When the Left O2 jumps off the floor it follows the rhs.
So check plugs/leads. check for flooded plug.

HTH
Mitch

Just seen other posts.

Yes check injectors but both sides are very lean.
checking plugs might indicate a cylinder or two not firing.

I get a simiar issue between 44 & 50 degrees where both O2's flatline then recover shortly after.
I've played with all setting without much success.
When motor is hot there are no issues

Mitch

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.

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

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..?

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.

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.

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

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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.

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Originally Posted by 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.

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Swapped 02's and the problem stays on bank 1

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Originally Posted by kur4o

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.

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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.

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Originally Posted by kur4o

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.

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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.

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.

Haha. That’s why i asked about the manifold!
Yes i had issue (may still have) with the Edelbrock LT4 manifold.
I remachined both faces as it was sucking air from underneath the ports.
I even bought the tool to measure the head face angles and the manifold angles. The manifold was off quite a bit.
I think i milled something like 0 to 0.007 top to bottom off both faces.
Also check front and rear china walls that it’s not sat up on them.

I am a bit dissapointed in the quality of the manifold
I also drilled out one of the front idle ports as it’s smaller than the others.
I could be wrong but I feel these ports could need to be bigger.

Oh and again BLM’s are maxed on both sides.



Mitch

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Originally Posted by 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.

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Thanks for the info. Yeah, I am starting to think this Edelbrock LT1 manifold may be the source of my ill's. I swapped over the OEM throttle body and it had no affect, so the 58mm one is back on there for now

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Originally Posted by Terminal_Crazy

Haha. That’s why i asked about the manifold! Yes i had issue (may still have) with the Edelbrock LT4 manifold. I remachined both faces as it was sucking air from underneath the ports.

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Thanks Mitch - you may have hit the nail on the head. I got the OEM intake off the shelf and started cleaning it up for re-installation within the next few days. We will see what sort of effect that has on all of this.

never used the edelbrock manifold, but in all my years of dealing with LT1 engines i've only heard of headaches, never any benefits

Easiest way to check the manifold when you clean it up...
check it's not sat on the front or back walls.(verylikely not as it will be sat up on the port faces.

lay 4 strips of some plumbers solder (about 2-3mm in diameter) across the port openings then snug the manifold down with a few bolts.

When you lift the manifold, measure the solder at the top & bottom of each port opening front to back.
There will probably be more clearance on the bottom. You are supposed to have a small clearance up at the top so the bottom fits in and the top is pulled up to the port faces.

You could try pumping propane into the valley through the rocker cover and watch the O2's/BLM's drop if it is sucking under there.

Good Luck
Mitch

Update: Huge air leak in the valley - both sides. The intake gaskets were a tick too small for the openings and as a result, it was sucking air. I have ordered the correct gaskets - which are not the FelPro LT1 - and we will see.

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I will pay a bounty to anyone that figures this out

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steveo
i'd say first check for a bigass vacuum leak

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cough cough ...

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Originally Posted by steveo

cough cough ...

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Check your resfilter email.

i was only kidding

thanks though

have you considered just swapping back to an oem manifold?

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Originally Posted by steveo

have you considered just swapping back to an oem manifold?

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Yes - that's what I set out to do yesterday. Have the manifold and gaskets ready to go. Once i saw the problem, though, I figured I'd give this thing one last shot. If it doesn't work, it only cost me $20 in gaskets and my time (outside of the purchase price of the manifold...)

Make sure you check the taper on the faces and the heads first.
Is it LT1 or LT4 manifold?
Just for my own interest.

Thanks
Mitch

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Originally Posted by Terminal_Crazy

Make sure you check the taper on the faces and the heads first.
Is it LT1 or LT4 manifold?
Just for my own interest.

Thanks
Mitch

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It's the LT1 specific model - the 7107. Interestingly enough, its powdercoated red, which according to Edelbrock is only available for the LT4 - but its stamped clear as day 7107. I don't have the taper gauge, but it appears to sit down just as it should on the heads. I'll run a feeler gauge around it and see what I come up with.

Update: Installed the Edelbrock with correct gaskets, which fixed the left 02 going super lean. Now they're both swinging as they should, but the car is still dumping fuel and sits at 160 blm at idle. MAF is still showing low-ish readings so I think it is still sucking air from somewhere. Pulling intake off and re-installing stocker, along with stock throttle body.

Update: Removed the Edelbrock intake, installed the stocker. MAF readings are back where they should be, vac readings are spot on. However, the BLM at idle is still around 150-153, with both sides showing lean/adding fuel. One side is +25, the other is +10-13. ICV counts are highish - hovering around 90, but throttle plates (Holley 58mm) are closed with the stop backed all the way off, and voltage set to .67v. The throttle body has *not* been drilled, and the Holley has the dedicated idle control circuit, just like the stocker.

Once it comes off idle, the trims pretty much fall back into shape and are very close. It's only at idle that things go weird. I understand that split BLM's are a common ailment in cammed LT1s, and even moreso with aftermarket tb's - but does anyone have any ideas?

I am going to remove the Holley and throw the stock unit back on and see what I see.

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ICV counts are highish - hovering around 90, but throttle plates (Holley 58mm) are closed with the stop backed all the way off, and voltage set to .67v

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that's good, that's how it should be.

if you don't have enough idle fuel and everything else runs ok, maybe just add some idle fuel. lets see a log of your warm idle

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Originally Posted by steveo

that's good, that's how it should be.

if you don't have enough idle fuel and everything else runs ok, maybe just add some idle fuel. lets see a log of your warm idle

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Thanks Steveo. I put the stock TB back on and the car straightened right up. Still have a split at idle, but it's only at +2/+11. I suspect I can get that down by tweaking fueling?

yep. Im sorry you had to figure out what i was trying to tell you a while ago. I dont come on the forums much anymore and just saw this thread. In the bottom of the eextra.xdf there is a setting for end of injection timing vs coolant temp. Add .2 to the entire table and check the trims again. you can calculate the difference in the stock cam overlap or more importantly the exhaust closing point of the current cam and extrapolate the needed number. This step before individual fueling adjustments. If your running long tubes id suggest set the entire table to 1.0 for individual fueling and use a temp gun outlined on fbodytech

Chris