2006 3/4 6.0 4l80e super lean

[Darkcloud]

Just got another truck. Its a 2006 3/4 chevy with 6.0 lq4, 4l80e,4wd, 4.10. Its a stock truck with 123k on it. Was running logs and trying to make it more peppy. Noticed it runs super lean on anything but idle. the LTFT is 15+ or more driving while STFT are in the 5+ range. I tried enabling fule enrichment at lower rpms and did some trans tuning. Truck seems really weak. Compared tune to a stock tune and only thing different is the PE and some trans tuning. Do these run this lean normally or is something wrong here? Truck just passed smog. IDK how with it running so lean. Here are the tune file and log.

[5FDP]

No, they don't normally run lean.

Look into your fuel pressure and check for vacuum leaks and exhaust leaks pre o2 sensor. Broken exhaust manifold bolts and intake gaskets are the most common issues if your fuel pressure is within spec.

[GHuggins]

Put a fuel pressure gauge on it and see if it's dropping off. The older trucks were bad for pumps, filters when equipped, mafs and cat issues. It shouldn't be that lean stock.

[Darkcloud]

Clean MAF and throttle body today. Performed throttle body relearn. No real change to how lean it is running. Question, if it was the cats, would they both go bad at the same time or would it be more of 1 or the other? During test drive, noticed that the O2 where switching normally. The lean running condition was pretty equal across both banks. That is telling me that is something that is effect both banks equally. Also, since it idles with no fuel added or subtracted. That would lead to a fueling issue right? Vacuum is really high at idle and sprayed carb cleaner around intake to check for leaks. None found. I guess a fuel pressure test is need now. Suppose to be 58-60psi at idle and 3000rpm right? Do I need to do a pressure decay test or just watch the pressure guage while running between idle and 3k rpm? Watching for it to drop below 55psi means pump is toast right? 2006 trucks don't have inline fuel filters right?

[kingtal0n]

Fuel filter
Injector cleaning
replace pcv valve (can leak excessive unmetered air)
pressure test intake
fuel pump sock
carbon buildup
maintenance issues
air filter and pcv system hoses

[Darkcloud]

Hey everyone, back again. So, I did a top end rebuild on my 3/4ton truck. While doing rebuild, found out why it was running lean and had some pinging under load. Had 2 broken exhaust bolts per head, the rest of the bolts where loose and spark plug electrodes where pretty much gone. Replaced 317heads with 706heads and installed Truck Norris camshaft. Everything else is stock. Stock injectors, stock intake tubs, stock exhaust manifolds and pipes but running true duals (3/4ton trucks have true duals till muffler from factory, just cut muffler off and replaced with 2 si/so chambered mufflers). So running around 10.5cr. Truck runs great and has a lot more power. I do not have wide band yet or 8.1 injectors yet. Waiting for funds. Just doing part throttle tuning for now to get it driving good until funds allow for them. Have not touched the spark tables yet. Adjusting the VE table first. Then MAF after. Running into super rich at idle (idle set to 750rpm hot) and rich in gear when idling at a light. Can someone take a quick look at my logs and tune for VE table please? Make sure I have it set up correctly and point in the right direction on leaning idle out. Have a cold start to warmed idle and a driving log for y'all to look at. I am at work and will check in around lunch time, 4.5-5hrs.

[Darkcloud]

Any thoughts? I don't think copying the LTFT from log and pasting it to VE table at %half is going to help much on the rich condition at idle. Seems like something else is causing it to run rich once engine settles into warm idle, in gear or not.

[kevin87turbot]

You'll just need to pull more fuel from the first three columns in the VE table. I've tuned a lot of those cams...you're on the right track.

[Darkcloud]

Ok cool, Just want to make sure I am on track. Strange that the mid range VE is pretty close with factory setting but idle and low rpm is far out. Anything else needs adjusting while doing this process? Like the base idle airflow or throttle follower?

[kevin87turbot]

Ok cool, Just want to make sure I am on track. Strange that the mid range VE is pretty close with factory setting but idle and low rpm is far out. Anything else needs adjusting while doing this process? Like the base idle airflow or throttle follower?

That's actually very typical of any similarly sized performance cam. The cam makes the engine very inefficient at idle and very low rpm. On the other hand, it will need more fuel above 3200 rpm or so...

The base airflow needs to be increased a bit more as well...probably need another 25-30% added at warm temps...

[Darkcloud]

Thanks for the info. I have another question. Why does my Idle vacuum get so low? Was looking through log and noticed at times it was at 10.3ish inHg at warm idle. Just the nature of the best with this sized cam or do I need more spark or is just because I am running only VE table right now?

[5FDP]

The scanners vacuum readings aren't exactly accurate when using that pid. A hand held vacuum gauge would show it better.

[Darkcloud]

Alright, a week of driving to tune VE and MAF. Got them within the +1 to -5 range. Idle is 0 to -3 depending on if A/C is on/off. Afterwards, loaded in stock LQ9 high and low spark tables. I have some knock issues (before and after loading LQ9 tables). Not sure if it is burst knock or actual knock. Do not hear knock when it registers on the spark retard table. Seems to knock on throttle transitions and when making shifts. Also registers knock when TC locks up around 50mph. Do I need to now adjust the burst knock tables now? black2500HDTRLQ9sparktable.hpt22-09-05 13-23-12.hpl

[5FDP]

Burst knock is something you can log. I'd honestly just set it to it's max of 8.00 and not ever worry about burst knock.

Seeing knock on transitions and at other weird times during normal driving can happen. Knock at part throttle does zero harm to the engine, some people end up chasing their tail forever on it. I'd only really care about knock when you stab the throttle and if there is a lot of it throughout a wide open throttle pull.

[Darkcloud]

So, slowly upgrading truck as I go along. Now have electric fan swap, airaid intake tube, and L59 36-37lb flexfuel injectors installed. Fine tuning as I go. Biggest change was doing the efan swap. Noticed more low/mid-range power. Did not change the tune other than turning on the efan in the tune. I did a lot of log driving today. Have some questions on it. First log is about an hour of driving, mostly highway. Reading knock it strange places. Towards the end of the log, I have a 2nd gear kick down and rpms jump to 5500rpm, was passing someone who jumped in front of me dong 60mph and I was doing 68-70mph. I have timing set around 21 but in the log, shows 23-24 and pulled 1 degree out at those high rpm. Is something wrong in the tune? Why is my timing higher than what I have it set to. On the second tune file. It is about 25min long and the whole log is lean. Not a lot, +1+2 range. I think this is ok, just want to make sure. Nothing changed in tune between the logs. What do yall think? Anything that I need to change? Also, have some low rpm knock counts. Is this a problem? Seems to count knock when PE is enabled. Is this because it is ramping fuel in too fast? Does not do it all the time.

[2xLS1]

What octane fuel are you using? If 87 you will get some occasional knock.

[kevin87turbot]

What octane fuel are you using? If 87 you will get some occasional knock.

You would typically run 93 octane on an application like this. It's a heavy truck and has 10.5 compression.

You didn't zero the base correction tables. That's why it's adding unwanted timing advance.

[Darkcloud]

Running 91 CA blend
Ok, I'll fix that in the tune and see what happens. Thank you

[Darkcloud]

So, put everything to zero. The fuel, IAT and ECT base, multi., and multi. 2?

[kevin87turbot]

So, put everything to zero. The fuel, IAT and ECT base, multi., and multi. 2?

I wouldn't do that. I would only zero the base fuel table...12626.